Corso aaroi besity intubation

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Corso aaroi besity intubation Corso aaroi besity intubation Presentation Transcript

  • Sottogruppo del file principale OBESITY AND INTUBATION
  • Perché intubare e ventilare? Perché non lasciare in respiro spontaneo? • 1 • Perché la curva CO2/risposta ventilatoria è spostata a dx …. • Respir Care. 2010 Nov;55(11):1442-8..Hypercapnic respiratory failure in obesityhypoventilation syndrome: CO₂ response and acetazolamide treatment effects.Raurich JM, Rialp G, Ibáñez J, Llompart-Pou JA, Ayestarán I. • • • • • Intensive Care Unit, Hospital Universitari Son Dureta, Andrea Doria 55, 07014, Palma de Mallorca, Illes Balears, Spain. joan.raurich@ssib.es Comment in: Respir Care. 2010 Nov;55(11):1504-5. Abstract OBJECTIVE: In obesity-hypoventilation-syndrome patients mechanically ventilated for hypercapnic respiratory failure we investigated the relationship between CO₂ response, body mass index, and plasma bicarbonate concentration, and the effect of acetazolamide on bicarbonate concentration and CO₂ response. METHODS: CO₂ response tests and arterial blood gas analysis were performed in 25 patients ready for a spontaneous breathing test, and repeated in a subgroup of 8 patients after acetazolamide treatment. CO₂ response test was measured as (1) hypercapnic drive response (the ratio of the change in airway occlusion pressure 0.1 s after the start of inspiratory flow to the change in P(aCO₂)), and (2) hypercapnic ventilatory response (the ratio of the change in minute volume to the change in P(aCO₂)). RESULTS: We did not find a significant relationship between CO₂ response and body mass index. Patients with higher bicarbonate concentration had a more blunted CO₂ response. Grouping the patients according to the first, second, and third tertiles of the bicarbonate concentration, the hypercapnic drive response was 0.32 ± 0.17 cm H₂O/mm Hg, 0.22 ± 0.15 cm H₂O/mm Hg, and 0.10 ± 0.06 cm H₂O/mm Hg, respectively (P = .01), and hypercapnic ventilatory response was 0.46 ± 0.23 L/min/mm Hg, 0.48 ± 0.36 L/min/mm Hg, and 0.22 ± 0.16 L/min/mm Hg, respectively (P = .04). After acetazolamide treatment, bicarbonate concentration was reduced by 8.4 ± 3.0 mmol/L (P = .01), and CO₂ response was shifted to the left, with an increase in hypercapnic drive response, by 0.14 ± 0.16 cm H₂O/mm Hg (P = .02), and hypercapnic ventilatory response, by 0.11 ± 0.22 L/min/mm Hg (P = .33). CONCLUSIONS: Patients with obesity-hypoventilation syndrome and higher bicarbonate concentrations had a more blunted CO₂ response. Body mass index was not related to CO₂ response. Acetazolamide decreased bicarbonate concentration and increased CO₂ response • • •
  • Airway-occlusion pressure 0.1 s after the start of inspiratory flow (P0.1) versus PaCO2, and minute volume (V˙ E) versus PaCO2,grouped according to the tertiles of BMI BMI tertile values were: first tertile 30–36 kg/m2, second tertile 36–42 kg/m2, third tertile 42–60 kg/m2. The first-tertile data points are indicated with squares. The second-tertile data points are indicated with circles. The third-tertile data points are indicated with triangles. The error bars represent sSE View slide
  • Collassibilità dello spazio retroglottico,sup e inf • 2 • severity of apnea in the obese group may be have been due to increased collapsibility of the upper airway rather than decreased size of the upper airway – polysomnography, cephalometry and dynamic multidetector computerized tomography (MD-CT) in wake and sleep states according to obesity. • Clin Exp Otorhinolaryngol. 2010 Sep;3(3):147-52. Epub 2010 Sep 17.Differences of Upper Airway Morphology According to Obesity: Study with Cephalometry and Dynamic MDCT.Kim TH, Chun BS, Lee HW, Kim JS View slide
  • high retropalatal (HRP), low retropalatal (LRP), high retroglossal (HRG), and low retroglossal (LRG). A minimal cross sectional area (mCSA) and collapsibility index (CI)
  • INTRODUCTION • Excellent intubating conditions are imperative for direct laryngoscopy and the efficient placement of a tracheal tube. • The proper positioning of a patient before induction is a key step. • Classic teaching has been to position the patient in the "sniffing" position, or supine with moderate head elevation and atlanto-occipital extension. – Bannister FB, Macbeth RG. Direct laryngoscopy and tracheal intubation. Lancet 1944;244, 6325:651–4
  • CRITERI PREDITTIVI;APPLICATI AGLI OBESI….
  • Non è che dobbiamo rivedere i criteri di valutazione esterni delle vie aeree? • Vedi articolo di Laryngoscope : • Clinical Predictors of Difficult Laryngeal Exposure
  • Ming-Wang Hsiung, Lu Pai, Bor-Hwang Kang, Bing-Long Wang, Chih-Shung Wong, Hsing-Won Wang, Clinical Predictors of Difficult Laryngeal Exposure.Laryngoscope, 114:358-363, 2004 • difficult laryngeal exposure following rigid laryngoscopy:predictors of DLE ? • 56 pts :a physical examination with age, sex, modified Mallampati index (MMI),body mass index (BMI), hyoid-mental distance (HMD),thyroid-mental distance (TMD), thyroid-mandible angle (TMA), horizontal thyroid distance (HTD), and vertical thyroid distance (VTD) • Stepwise regression employed on patient data to identify those with DLE. • sex (P = .045,odds ratio = 69.159) and TMA (P = .004, odds ratio =1.510) to be "reliable" DLE predictors. • Using these 2 variables, 94.6% of study case patients could have been correctly classified preoperatively. Based on our comparison of case results, we found that a TMA value >120 degrees in men and 130 degrees in women indicates a strong likelihood of DLE.
  • Hyoid mental distance (HMD) and thyroid mental distance (TMD)
  • Vertical thyroid distance (VTD)and horizontal thyroid distance(HTD)
  • TMA can be regarded as a composite of the tongue, mandible,and epiglottis during a rigid laryngoscope procedure. Tiroid mandible angle:TMA
  • • • • • Preoperative airway assessment: predictive value of a multivariate risk index Anesth Analg. 1996 Jun;82(6):1197-204.. el-Ganzouri AR, McCarthy RJ, Tuman KJ, Tanck EN, Ivankovich AD. Source Department of Anesthesiology, Rush-Presbyterian-St. Luke's Medical Center at Rush Medical College, Chicago, Illinois 60612, USA. • 10,507 consecutive patients • prospectively assessed prior to general anesthesia with respect to • mouth opening, thyromental distance, oropharyngeal (Mallampati) classification, neck movement, ability to prognath, body weight, and history of difficult tracheal intubation. • After induction of anesthesia, the laryngeal view during rigid laryngoscopy was graded and the ability of experienced anesthesia personnel to ventilate via a mask was determined. • Poor intubating conditions (laryngoscopy Grade IV) and inability to achieve adequate mask ventilation were identified in 107 (1%) and 8 (0.07%) cases, respectively. • • Logistic regression identified all seven criteria as independent predictors of difficulty with laryngoscopic visualization. A composite airway risk index (derived from nominalized odds ratios calculated from the multivariate model) as well a simplified (0 = low, 1 = medium, 2 = high) risk weighting exhibited higher positive predictive value for laryngoscopy Grade IV at scores with similar sensitivity to Mallampati class III, as well as higher sensitivity at scores with similar positive predictive value. Compared to Mallampati class I fewer false-negative predictions were observed at a risk index value of 0. We conclude that improved risk stratification for difficulty with visualization during rigid laryngoscopy (Grade IV) can be obtained by use of a simplified preoperative multivariate airway risk index, with better accuracy compared to oropharyngeal (Mallampati) classification at both low- and high-risk levels.
  • SAR: (simplified airway risk index,SAR index) Described by El-Ganzouri et al.: El-Ganzouri AR, McCarthy RJ, Tuman KJ, et al. Preoperative airway assessment: predictive value of a multivariate risk index. Anesth Analg 1996;82:1197–204 • assigned a value of 0,1, or 2 to the following risk factors: – – – – – – MO (>35 mm, 0;<35 mm, 1), TMD (>65 mm, 0; 60–65 mm, 1; <60 mm,2), Mallampati score (I, 0; II, 1; III or IV, 2), Cervical spine extension (90°, 0; 80°–90°, 1; 80°, 2), body weight (90 kg, 0; 90–110 kg, 1; 110 kg, 2), history of difficult intubation (none, 0; questionable, 1;definite, 2). • A SAR score 4 categorized the patient as at risk for difficult intubation
  • Prediction of difficult tracheal intubation • Iohom G, Ronayne M, Cunningham AJ.Eur J Anaesthesiol. 2003 • • • • • • Jan;20(1):31-6. . • Source Beaumont Hospital, Department of Anaesthesia and Intensive Care, Dublin, Ireland. iohom@hotmail.com Abstract BACKGROUND AND OBJECTIVE: Preoperative bedside screening tests for difficult tracheal intubation may be neither sensitive nor specific enough for clinical use. The aim was to investigate if a combination of the Mallampati classification of the oropharyngeal view with either the thyromental or sternomental distance measurement improved the predictive value. METHODS: A total of 212 (109 male, 103 female) non-obstetric surgical patients, aged >18 yr, undergoing elective surgical procedures requiring tracheal intubation were assessed preoperatively with respect to the oropharyngeal (modified Mallampati) classification, thyromental and sternomental distances. An experienced anaesthetist, blinded to the preoperative airway assessment, performed laryngoscopy and graded the view according to Cormack and Lehane's classification. RESULTS: Twenty tracheal intubations (9%) were difficult as defined by a Cormack and Lehane Grade 3 or 4, or the requirement for a bougie in patients with Cormack and Lehane Grade 2. Used alone, the Mallampati oropharyngeal view, and thyromental and sternomental distances were associated with poor sensitivity, specificity and positive predictive values. Combining the Mallampati Class III or IV with either a thyromental distance <6.5cm or a sternomental distance <12.5cm decreased the sensitivity (from 40 to 25 and 20%, respectively), but maintained a negative predictive value of 93%. The specificity and positive predictive values increased from 89 and 27% respectively for Mallampati alone to 100%. CONCLUSIONS: • The findings suggest that the • • • • Mallampati classification, in conjunction with measurement of the thyromental and sternomental distances, may be a useful routine screening test for preoperative prediction of difficult tracheal intubation
  • Predicting Difficult Intubation in Apparently Normal Patients.A Meta-analysis of Bedside Screening Test Performance
  • MASK VENTILATION
  • Anesth Analg. 2009 Dec;109(6):1870-80.Difficult mask ventilation.El-Orbany M, Woehlck HJ. • Mask ventilation is the most fundamental skill in airway management. I • n this review, we summarize the current knowledge about difficult mask ventilation (DMV) situations. Various definitions for DMV have been used in the literature. The lack of a precise standard definition creates a problem for studies on DMV and causes confusion in data communication and comparisons. DMV develops because of multiple factors that are technique related and/or airway related. Frequently, the pathogenesis involves a combination of these factors interacting to cause the final clinical picture. The reported incidence of DMV varies widely (from 0.08% to 15%) depending on the criteria used for its definition. Obesity, age older than 55 yr, history of snoring, lack of teeth, the presence of a beard, Mallampati Class III or IV, and abnormal mandibular protrusion test are all independent predictors of DMV. These signs should, therefore, be recognized and documented during the preoperative evaluation. DMV can be even more challenging in infants and children, because they develop hypoxemia much faster than adults. Finally, difficult tracheal intubation is more frequent in patients who experience DMV, and thus, clinicians should be familiar with the corrective measures and management options when faced with a challenging, difficult, or impossible mask ventilation situation
  • Definition of difficult mask ventilation (DMV) • 1993, ASA Task Force on Management of the Difficult Airway : • “DMV is a situation that develops when it is not possible for the unassisted anesthesiologist to maintain the oxygen saturation 90% using 100% oxygen and positive pressure ventilation, or to prevent or reverse signs of inadequate ventilation.”
  • Studies on difficult mask ventilation:1 • prospective study of 1502 patients, multivariate analysis of preoperative findings that were correlated with DMV. They found 5 risk factors to be significantly associated with DMV and thus may be used as predictors. These were: • age > 55 yr • body mass index (BMI)> 26 kg/m2 • lack of teeth • history of snoring, • presence of a beard. • The presence of at least t 2 of these factors indicated a high likelihood of DMV. – Langeron O, Masso E, Huraux C, Guggiari M, Bianchi A, Coriat P, Riou B. Prediction of difficult mask ventilation. Anesthesiology 2000;92:1229–36
  • Studies on difficult mask ventilation:2 e 3 • • • • • • age, Weight history of snoring male gender Mallampati Class IV significantly associated with DMV. – • • • • • • • • Yildiz TS, Solak M, Toker K. The incidence and risk factors of difficult mask ventilation. J Anaesth 2005;19:7–11 multivariate regression analysis:independent predictors for Grade 3 MV (DMV). age > than 57 yr, BMI > 30, history of snoring the presence of a beard, Mallampati Class III or IV, limited mandibular protrusion test In contrast, however, they were not able to identify lack of teeth as a predictor. They also identified history of snoring and thyromental distance of 6 cm as predictors of Grade 4 MV (IMV). – . Kheterpal S, Han R, Tremper KK, Shanks A, Tait AR, O’Reilly,M, Ludwig TA. Incidence and predictors of difficult and impossible mask ventilation. Anesthesiology 2006;105:885–91
  • Anesthesiology. 2006 Nov;105(5):885-91. Incidence and predictors of difficult and impossible mask ventilation. Kheterpal S, Han R, Tremper KK, Shanks A, Tait AR, O'Reilly M, Ludwig TA. • 4 point scale to grade difficulty in performing mask ventilation (MV) : – grade 3 MV =(inadequate, unstable, or requiring two providers) – grade 4 MV (impossible to ventilate) – difficult intubation. During a 24-month period, 22,660 attempts at MV 313 cases (1.4%) of grade 3 MV, 37 cases (0.16%) of grade 4 MV, and 84 cases (0.37%) of grade 3 or 4 MV and difficult intubation • CONCLUSIONS: • The authors observed the incidence of grade 3 MV to be 1.4%, similar to studies with the same definition of difficult MV. Presence of a beard is the only easily modifiable independent risk factor for difficult MV. The mandibular protrusion test may be an essential element of the airway examination
  • Risultati dallo studio di Ketherpal et al : • Predictors of grade 3 mask ventilation: • • • • • • Body mass index of 30 kg/m or greater a beard, Mallampati classification III or IV, age of 57 yr or older, severely limited jaw protrusion, Snoring • Predictors of grade 4 mask ventilation: • • Snoring thyromental distance <6 cm • predictors of grade 3 or 4 MV and difficult intubation • • • • • Limited or severely limited mandibular protrusion abnormal neck anatomy, sleep apnea, snoring, body mass index of 30 kg/m or greater
  • Conclusioni sulla difficile ventilazione in maschera: • Tutti gli autori concordano che: • BMI>30 • Mallampati 3 e 4 • Russamento • Sono tutti predittivi!e quindi tutti gli obesi presentano potenzialmente questo problema!
  • Methods to secure airway in Obese patients: • • • • • • • • Intubation after induction Awake fibreoptic intubation Various Laryngeal mask airways (LMAs) LMA-fastrach LMA Ctrach Glidescope AirtraqTM laryngoscope Etc….
  • PREMESSA E METANALISI
  • • Several reviews have reported that endotracheal intubation is more difficult in obese than in lean patients . • However, this assertion remains debated because others studies have found no evidence that tracheal intubation is more difficult in obese than in lean individuals . • One of the reasons for these discrepancies is the lack of consensus on the definition of the term “difficult intubation,” which varies between authors.
  • • Yes: • • • • • • • • Obese pts are more difficult to intubate? Benumof JL. Management of the difficult adult airway: with special emphasis on awake tracheal intubation. Anesthesiology 1991;75:1087–110. Adams JP, Murphy PG. Obesity in anaesthesia and intensive care. Br J Anaesth 2000;85:91–108. Fox GS, Whalley DG, Bevan DR. Anaesthesia for the morbidly obese: experience with 110 patients. Br J Anaesth 1981;53:811–6. Shenkman Z, Shir Y, Brodsky JB. Perioperative management of the obese patient. Br J Anaesth 1993;70:349– 59. Voyagis GS, Kyriakis KP, Dimitriou V, Vrettou I. Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients. Eur J Anaesthesiol 1998;15:330–4. Wilson ME, Spiegelhalter D, Robertson JA, Lesser P. Predicting difficult intubation. Br J Anaesth 1988;61:211– 6. YES/NO Lavi R, Segal D, Ziser A. Predicting difficult airways using the intubation difficulty scale: a study comparing obese and non-obese patients. J Clin Anesth. 2009 Jun;21(4):264-7.;IDS score higher in obese,but duration of intubation = • NO: • • • Karkouti K, Rose DK, Wigglesworth D, Cohen MM. Predicting difficult intubation: a multivariable analysis. Can J Anaesth 2000;47:730–9. Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid obesity and tracheal intubation. Anesth Analg 2002;94:732–6. Bond A. Obesity and difficult intubation. Anaesth Intensive Care 1993;21:828–30.
  • The Association Between Obesity and Difficult Prehospital Tracheal Intubation • • • • • • • • • Timothy J. Holmberg, Stephen M. Bowman, Keir J. Warner,Monica S. Vavilala,Eileen M. Bulger,Michael K. Copass, Sam R. Sharar,. retrospective review all patients ≥15 years of age who underwent prehospital trch.intub by paramedics Seattle Medic One system over a 4-year period, Pts transported to the regional level 1 trauma center (Harborview Medical Center) Data were abstracted from a prospectively collected prehospital airway management database and from the hospital medical records, including demographic information, number of TI attempts, TI success or failure, and body weight/height (BMI). RESULTS: Of 80,501 patient contacts in whom 4114 TIs were attempted during the 4-year study period, 823 met study entry criteria (including a calculable BMI). The overall TI success rate in the study population was 98.5% (811 out of 823), with 6.8% (56 out of 823) meeting the predetermined definition for difficult TI. There was no significant association between difficult TI and patient age, gender, use of succinylcholine, or medical diagnosis (trauma vs. nontrauma). In comparison with the lean patient subgroup (BMI <30 kg/m2), patients with class III obesity (BMI >40 kg/m2) had a significant association with difficult TI (odds ratio 3.68; confidence interval [CI] 1.27–10.59), whereas those with class I/II obesity (BMI ≥30 kg/m2 and <40 kg/m2) did not (odds ratio 0.98; CI 0.46 –2.07). CONCLUSIONS: Among prehospital ALS providers with previously documented and published successful TI performance, increased difficulty with TI was observed in patients with extreme obesity, but not in patients with lesser degrees of obesity. Because extreme obesity is an easily identifiable patient characteristic, didactic and clinical (e.g., operating room) airway management education for such providers should emphasize airway management challenges and strategies associated with obesity, including specific equipment, patient positioning, and practice recommendations that may facilitate both TI and alternative airway management techniques in this population.
  • Casistica retrospettiva Memorial Hospital Houston,Texs • 283 obese patients: • Fibrobroncoscopia + frequente in: • BMI > or = 60 kg/m2 (P < 0.001) • Mallampati class III or IV airway (P < 0.001) • Male (P = 0.004). • These three factors were also statistically significant in the multivariate logistic regression. In particular, each one kg/m(2) increase in BMI was associated with a 7% increased likelihood of AFI. Men were approximately 4 times likelier than women to have an AFI. Compared with patients with a Mallampati Class I or II airway, those with Mallampati Classes III or IV were about 26 times as likelier to have an AFI. • No failed intubations
  • PER ES,ANCHE UNA METANALISI…….
  • Shiga T, Wajima Z, Inoue T, Sakamoto A: Predicting difficult intubation in apparently normal patients: A meta-analysis of bedside screening test performance.ANESTHESIOLOGY 2005; 103:429–37 • • • • • • to systematically determine the diagnostic accuracy of bedside tests for predicting difficult intubation in patients with no airway pathology Thirty-five studies (50,760 patients) were selected from electronic databases. overall incidence of difficult intubation was 5.8% (95% confidence interval, 4.5-7.5%). Screening tests included the Mallampati oropharyngeal classification, thyromental distance, sternomental distance, mouth opening, and Wilson risk score. Each test yielded poor to moderate sensitivity (20-62%) and moderate to fair specificity (82-97%). The most useful bedside test for prediction was found to be a combination of the Mallampati classification and thyromental distance (positive likelihood ratio, 9.9; 95% confidence interval, 3.131.9). • Currently available screening tests for difficult intubation have only poor to moderate discriminative power when used alone. Combinations of tests add some incremental diagnostic value in comparison to the value of each test alone. The clinical value of bedside screening tests for predicting difficult intubation remains limited(vedi la diapo precedente) • Obese subgroup : obese patients are three times more difficult to intubate than their slimmer counterparts.
  • Predicting Difficult Intubation in Apparently Normal Patients.A Meta-analysis of Bedside Screening Test Performance
  • La loro asserzione finale è smentita dall’analisi dei lavori che essi stessi hanno citato….. • 378 patients in the studies they reviewed, and every patient except one was intubated successfully by direct laryngoscopy. • All 4 of the studies they analyzed specifically stated that the magnitude of obesity does not influence laryngoscopy difficulty.
  • Punti da chiarire : • 1)Difficult laryngoscopy is not synonimous of difficult intubation • 2)ASA Task Force on the management of the difficult airway defines a difficult airway” • as the “clinical situation in which a conventionally trained anesthesiologist experiences problems with (a) face mask ventilation of the upper airway or (b) tracheal intubation, or both.”
  • Limitations of the metaanalysis • Sniff position: • achieved in nonobese patients by raising the occiput 8 to 10 cm with a pillow or head rest, obese patients require much greater elevation of their head, neck, and shoulders to produce the same alignment of axes for intubation. • It has been demonstrated that elevating the upper body and head of morbidly obese patients to align their sternum and ear in a horizontal line (head-elevated laryngoscopy position) results in significant improvement in laryngoscopic view. – Collins JS, Lemmens HJ, Brodsky JB, Brock-Utne JG, Levitan RM. Laryngoscopy and morbid obesity: A comparison of the “sniff” and ramped positions. Obes Surg 2004;14:1171–5. • In two of Shiga et al.’s four references, head position was described only as sniffing and may therefore have been suboptimal. Suboptimal positioning would result in a higher incidence of grade 3 and 4 CormackLehane laryngoscopy views, making direct laryngoscopy and hence tracheal intubation more challenging. Until a standard intubating position for obese patients is adopted for research purposes, comparing studies using different positions will continue to confound the issue.
  • Methodological limitations of the studies • noncomparative studies (4,19) • small numbers of patients (7,20) – study showing that intubation was more difficult in obese than in nonobese women during delivery, the statistical analysis included only 17 and 8 patients in these 2 groups, respectively (20) – Wilson et al. (7), who identified obesity as a risk factor for difficult intubation, were able to include only two obese patients and one lean patient with intubation difficulties. • Failure to distinguish between difficult intubation and difficult laryngoscopy. The two do not necessarily go together, however. For instance, in our study, intubation was more difficult in the obese patients,whereas the incidence of difficult laryngoscopy (i.e., Cormack class III or IV) was similar in obese and lean patients. This is not surprising, because factors complicating laryngoscopy do not reflect the full spectrum of complex events that can make intubation difficult or easy. • the negative previous studies, which suggested that obesity and weight were not risk factors for difficult intubation, also failed to distinguish between difficult intubation and difficult laryngoscopy (1,6,8,9). In addition, some of these studies were performed with a small number of patients (9), without
  • Classification of papers on intubation in obese patients author patients BMI surgery Position anesthes Cormack Intub for intub ia diff
  • • the magnitude of obesity does not influence laryngoscopy difficulty • Prediction of difficult laryngoscopy in obese patients by ultrasound quantification of anterior neck soft tissue. Anaesthesia 2003; 58:1111–4 • • • Juvin P, Lavaut E, Dupont H, Lefevre P, Demetriou M, Dumoulin JL, Desmonts JM: Difficult tracheal intubation is more common in obese than in lean patients. Anesth Analg 2003; 97:595–600 Brodsky JB, Lemmens HJ, Brock-Utne JG, Vierra M, Saidman LJ: Morbid obesity and tracheal intubation. Anesth Analg 2002; 94:732–6 Voyagis GS, Kyriakis KP, Dimitriou V, Vrettou I: Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients.Eur J Anaesthesiol 1998; 15:330–4
  • need for a clinically relevant definition of difficult intubation • IDS score •…vedi oltre)
  • Conclusions: • Only superobese may be difficult to intubate? • Out of hospital ALS: • • The Association Between Obesity and Difficult Prehospital Tracheal Intubation.Holmberg TJ, Bowman SM, Warner KJ, Vavilala MS, Bulger EM, Copass MK, Sharar SR. Asthma. 2011 Apr;48(3):21723. Epub 2011 Feb 21. • University of Washington, Seattle, Washington; • In comparison with the lean patient subgroup (BMI <30 kg/m(2)), patients with class III obesity (BMI >40 kg/m(2)) had a significant association with difficult TI (odds ratio 3.68; confidence interval [CI] 1.27-10.59), whereas those with class I/II obesity (BMI ≥30 kg/m(2) and <40 kg/m(2)) did not increase in BMI was associated with a 7% increased likelihood of AFI. Men were approximately 4 times likelier than women to have an AFI. Compared with patients with a Mallampati Class I or II airway, those with Mallampati Classes III or IV were about 26 times as likelier to have an AFI. •
  • MALLAMPATI COME CRITERIO PREDITTIVO,MA A COLLO ESTESO +DIABETE………………….
  • Voyagis, G. S.; Kyriakis, K. P.; Dimitriou, V.; Vrettou, I.Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients. European Journal of Anaesthesiology 1998,15: 330-334 • 99 obese patients • Mallampati poor predictor
  • Intubation difficulties Voyagis, G. S.; Kyriakis, K. P.; Dimitriou, V.; Vrettou, I.Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients. European Journal of Anaesthesiology 1998,15: 330-334 : 20.2% 25 20 15 7.6% 10 5 0 diff.intubation nonobese obese
  • posterior pharynx visible OroPharyngeal classification Voyagis, G. S.; Kyriakis, K. P.; Dimitriou, V.; Vrettou, I.Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients. European Journal of Anaesthesiology 1998,15: 330-334 Protrusione forzata della lingua migliora la predittività nonobese 15 obese 10 5 not visible
  • Conclusions: Voyagis, G. S.; Kyriakis, K. P.; Dimitriou, V.; Vrettou, I.Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients. European Journal of Anaesthesiology 1998,15: 330-334 • Whenever obesity is accompanied by an inability to see the posterior pharyngeal wall, an elective awake intubation should be considered.
  • The extended Mallampati score and a diagnosis of diabetes mellitus are predictors of difficult laryngoscopy in the morbidly obese.Mashour GA, Kheterpal S, Vanaharam V, Shanks A, Wang LY, Sandberg WS, Tremper KK. Anesth Analg. 2008 Dec;107(6):1919-23 predictive value of the MMP is improved when the patient's craniocervical junction is extended rather than neutral (Extended Mallampati Score, EMS). In the present study, we compared the predictive value of the MMP and EMS in the morbidly obese. • Previous studies have demonstrated that the • • METHODS: We performed a prospective study of adult patients with a Body Mass Index (BMI) > or = 40 over a 12-mo period comparing the MMP and EMS. The performance of the MMP, EMS, and other commonly used tests was compared for the ability to predict difficult laryngoscopy, defined as a CormackLehane grade of 3 or 4. Positioning and direct laryngoscopic techniques were not standardized. The incidence of difficult laryngoscopy and difficult intubation was compared in patients with BMI > or = or < 40. RESULTS: Three-hundred-forty-six patients with a BMI > or = 40 were evaluated with both the MMP and EMS and received direct laryngoscopy. On average, craniocervical extension decreased the MMP class (P < 0.0001). Compared to the MMP, the EMS improved specificity and predictive value while maintaining sensitivity. Compared to the MMP and other tests, an EMS class of 3 or 4 and a diagnosis of diabetes mellitus were the only statistically significant predictors of difficult laryngoscopy in the morbidly obese. There was no difference in the incidence of difficult laryngoscopy or intubation in the morbidly obese compared to patients with a BMI < 40. CONCLUSIONS: • • • • The EMS was superior to the MMP in the prediction of difficult laryngoscopy in the morbidly obese population. • A diagnosis of diabetes mellitus also warrants further investigation as a predictor of difficult laryngoscopy in this population. • Finally, this study supports previous findings that morbid obesity is not itself a predictor of difficult laryngoscopy or intubation
  • The extended Mallampati score and a diagnosis of diabetes mellitus are predictors of difficult laryngoscopy in the morbidly obese. Anesth Analg. 2008 Dec;107(6):1919-23 Mashour GA, Kheterpal S, Vanaharam V, Shanks A, Wang LY, Sandberg WS, Tremper KK 1)estensione forzata del collo > posizione neutra nella predittività della laringoscopia difficile 2) il diabete aumenta il rischio di laringoscopia difficile
  • Dallo studio di Mashour:suggerimenti per una lista preop.di valutazione delle vie aeree • • • • • • • • • • • • • • • Cervical spine (limited extension, limited flexion, known unstable, possible unstable) Neck anatomy (limited laryngeal mobility, mass, radiation changes, thick/obese, thyroid cartilage not visible,tracheal deviation) Thyroid cartilage to mentum distance (6 cm, 6 cm) Mouth opening interincisor or intergingival distance (3 cm, 3 cm) Mandibular protrusion test (normal: lower incisors can be protruded anterior to upper incisors, limited: lower incisors can be advanced to only meet upper incisors,severely limited: lower incisors cannot be advanced to meet upper incisors) Mallampati classification (I, II, III, or IV) as modified by Samsoon and Young. Performed with patient sitting with head in neutral or extended position, mouth maximally open, tongue maximally protruded, without phonation Full beard (yes, no, moustache, or goatee) Dentition (normal, dentures upper partial, dentures upper complete, dentures lower partial, dentures lower complete, edentulous, teeth missing/loose/broken) History of cough (chronic, recent, productive, nonproductive) History of rhinorrhea History of chronic obstructive pulmonary disease (chronic bronchitis or emphysema requiring treatment with inhaled or systemic steroids or bronchodilators) History of asthma (requiring treatment with inhaled or systemic steroids or bronchodilators) History of snoring occurring nightly History of obstructive sleep apnea (requiring continuous positive airway pressure, bilevel positive airway pressure, or surgery) Airway evaluations are nonquantitative and based on physical examination, unless otherwise noted.
  • . Neligan PJ, Porter S, Max B, Malhotra G, Greenblatt EP, Ochroch EA. Obstructive sleep apnea is not a risk factor for difficult intubation in morbidly obese patients. Anesth Analg. 2009 Oct;109(4):1182-6 • Department of Anaesthesia and Critical Care, Hospital of University of Pennsylvania, Philadelphia, PA, USA. • • • 180 pts for bariatric surgery, mean BMI was 49.4 kg/m(2 predictive factors tested: OSA and its severity, as determined by apnea-hypopnea index (AHI), gender, NC, and body mass index (BMI). standardized anesthetic that included positioning in the "ramped position" for direct laryngoscopy. All the patients' tracheas were intubated successfully without the aid of rescue airways by anesthesiology residents. 6 patients required 3 or + intubation attempts, a difficult intubation rate of 3.3%. 8.3% incidence of difficult laryngoscopy, defined as a Cormack and Lehane Grade 3 or 4 view. no relationship between NC and difficult intubation (odds ratio 1.02, 95% confidence interval 0.931.1), between the diagnosis of OSA and difficult intubation (P = 0.09), or between BMI and difficult intubation (odds ratio 0.99, 95% confidence interval 0.92-1.06, P = 0.8). There was no relationship between number of intubation attempts and BMI (P = 0.8), AHI (P = 0.82), or NC (P = 0.3). Mallampati Grade III or more predicted difficult intubation (P = 0.02), as did male gender (P = 0.02). Finally, there was no relationship between Cormack and Lehane grade and BMI (P = 0.88), AHI (P = 0.93), or OSA (P = 0.6). I ncreasing NC was associated with difficult laryngoscopy but not difficult intubation (P = 0.02). • CONCLUSIONS: • In MO patients undergoing bariatric surgery in the "ramped position," there was no relationship between the presence and severity of OSA, BMI, or NC and difficulty of intubation or laryngoscopy grade. Only a Mallampati score of 3 or 4 or male gender predicted difficult intubation • • • • • •
  • Criticism(my) of Neligan et al • “ramped” position by stacking blankets behind the patient’s back, resulting in elevation of the head, upper body, and shoulders significantly above the chest.: the external auditory meatus was horizontal with the sternal notch, and this was checked by a trained observer in each patient. • standardized induction of anesthesia with propofol (1–2 mg/kg) and fentanyl (1–2 g/kg),and neuromuscular blockade achieved with vecuronium (0.1 mg/kg) or succinylcholine (1 mg/kg). • The first three laryngoscopic attempts were to be performed by an anesthesiology resident. Subsequent attempts were to be performed by an attending anesthesiologist, in keeping with clinical practice at our institution. • PreO2????
  • Conclusion from Neligan et al. • OSA is not predictive of difficult intubation in obese • (positioning in the “ramped position” for direct laryngoscopy) • Only a Mallampati score of 3 or 4 or male gender predicted difficult intubation • vedi la loro discussione
  • ALLORA VEDIAMO UN POCO LA LETTERATURA;COMINCIAMO A DEFINIRE LA INTUBAZIONE DIFFICILE ……………….
  • Tra l’altro,le vie aree degli obesi sono più reattive…. • Allergy Asthma Proc. 2011 Jan;32(1):68-73. • Association between subcutaneous abdominal fat and airway hyperresponsiveness. • Kim KM, Kim SS, Kwon JW, Jung JW, Kim TW, Lee SH, Min KU, Kim YY, Cho SH. • • • Department of Internal Medicine, Dankook University College of Medicine, Cheonan-si, Chungcheongnamdo, Korea. Abstract Epidemiological studies have shown that obesity is significantly associated with airway hyperresponsiveness (AHR). The aim of this study was to determine the effect of abdominal fat distribution on the prevalence of AHR. This study was conducted on subjects who visited the Seoul National University Hospital Gangnam Center from October 2003 to January 2009. Medical records of 3205 subjects who had both a methacholine bronchial provocation test and an abdominal CT scan were retrospectively reviewed. One hundred sixty-one subjects with AHR and their 161 controls were selected for the analysis. Total, subcutaneous, and visceral abdominal fat were objectively measured by an abdominal CT scan. Both body mass index (BMI) and waist circumference were significantly associated with AHR after adjustment for smoking (BMI: OR, 1.20; 95% confidence interval [CI], 1.071.35; waist circumference: OR, 1.07; 95% CI, 1.02-1.11). Total and subcutaneous abdominal fat increased the risk of AHR with an OR of 1.47 (95% CI, 1.08-2.02) in the case of total abdominal fat, and an OR of 1.99 (95% CI, 1.193.31) in the case of subcutaneous abdominal fat. However, visceral abdominal fat was not associated with AHR. The association between subcutaneous abdominal fat and AHR was consistent, especially in men. Subcutaneous abdominal fat was significantly associated with AHR, but visceral abdominal fat was not. These results suggest a possible role for subcutaneous fat on the later development of asthma.
  • Intubation difficulty assessment(score) • IDS developed by Adnet et al. (10) – Adnet F, Borron SW, Racine SX, et al. The intubation difficultyscale (IDS): proposal and evaluation of a new score characterizing the complexity of endotracheal intubation. Anesthesiology 1997;87:1290–7. on the basis of 7 variables associated with difficult intubation.
  • IDS score • is the sum of N1 through N7. • A score of 0 indicated intubation under ideal conditions, performed on the first attempt by the first operator, who used a single technique and applied minimal force to insert the tube through a fully visualized glottis. • An IDS score from 1 to 5 indicated slight difficulty • an IDS score 5 or +indicated moderate to major difficulty.
  • Difficult Tracheal Intubation Is More Common in Obese Than in Lean Patients Juvin P., Lavaut E, Dupont H, Lefevre P, Demetriou M, Dumoulin JL, Desmonts JM.Anesth Analg 2003;97:595–600) • 140 obese • No intubation impossible • The incidence of difficult intubation was more frequent in the obese than in the lean patients
  • Difficult Tracheal Intubation Is More Common in Obese Than in Lean Patients Juvin P., Lavaut E, Dupont H, Lefevre P, Demetriou M, Dumoulin JL, Desmonts JM.Anesth Analg 2003;97:595–600) semirecumbent position (30°) with the head in the sniffing position PreO2 propofol (2–2.5 mg/kg) + succi (1 mg/kg) Cricoid pressure( Sellick) Macintosh No. 3 laryngoscope blade always 70 60 50 IDS 0 40 IDS>1 <5 30 IDS=>5 overall difficulty 20 10 0 lean obese
  • Difficult Tracheal Intubation Is More Common in Obese Than in Lean Patients Juvin P., Lavaut E, Dupont H, Lefevre P, Demetriou M, Dumoulin JL, Desmonts JM.Anesth Analg 2003;97:595–600) • Mallampati score of III or IV was an independent risk factor for difficult intubation in obese patients, whereas obesity (i.e., BMI) was not. • The sensitivity of the Mallampati score was 100% and 85%, its specificity was 74% and 62%, its positive predictive value was 8% and 29%, and its negative predictive value was 100% and 96% in lean and obese patients, respectively.
  • Difficult Tracheal Intubation Is More Common in Obese Than in Lean Patients Juvin P., Lavaut E, Dupont H, Lefevre P, Demetriou M, Dumoulin JL, Desmonts JM.Anesth Analg 2003;97:595–600)
  • Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid obesity and tracheal intubation. Anesth Analg. 2002;94(3):732–736 • • • • • • • • • • • • • • 78 women and 22 men aged 44 yr (interquartile range, 36 –51 yr) were studied Weight was 137 kg (interquartile range, 124 –156 kg) height was 168 cm (interquartile range, 160 –173 cm) BMI was 47.5 kg/m2 (interquartile range, 43.9 –56.6 kg/m2). Forty-four patients had a history suggestive or diagnostic of OSA; 56 had no evidence of OSA. The median neck circumference was 46.0 cm (interquartile range, 42.0–49.0 cm), the sternomental distance was 14.0 cm (interquartile range, 12.0–17.0 cm), thyromental distance was 9.5 cm (interquartile range, 8.0–11.0 cm). In 30, 37, 32, and 1 patients, Mallampati scores were 1, 2, 3, and 4, respectively. during initial laryngoscopy, the view of the larynx was Grade 1 in 75 patients, Grade 2 in 16 patients, and Grade 3 in 9 patients. No patient had a Grade 4 view. In 92, 5,and 2 patients, the trachea was intubated on the first, second, and third attempts, respectively. A failed intubation with direct laryngoscopy occurred in one patient. In 97 patients the tracheas were intubated by the anesthesia resident; 3 patients required intubation by
  • Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid obesity and tracheal intubation. Anesth Analg. 2002;94(3):732–736 • The logistic regression model predicts that the odds of a problematic intubation in a particular patient with a neck circumference 1cm larger than that of another patient are 1.13 (95% CI, 1.02 to 1.25) times the odds of the patient with a 1 cm smaller neck circumference. Therefore a 40 cm neck circumference carries a 5% probability of problematic intubation and at 60 cm the probability rises to 35%.
  • Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid obesity and tracheal intubation. Anesth Analg. 2002;94(3):732–736
  • Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid obesity and tracheal intubation. Anesth Analg. 2002;94(3):732–736 A larger neck circumference was associated • • • • with: men (P 0.001), a higher Mallampati score (P 0.0029), Grade 3 views during laryngoscopy (P 0.0375) OSA (P 0.0372)
  • Conclusions • neither absolute obesity nor increasing BMI was associated with problematic intubation in morbidly obese patients. • Problematic intubation was associated with increasing neck circumference and a Mallampati score = >3. • A poor view during direct laryngoscopy was not a factor in successful intubation because in all but one patient the trachea was intubated by direct laryngoscopy • The experience and ability of the laryngoscopist are probably the most important determinants for establishing an airway in the morbidly obese patient. • Because anesthesia residents successfully intubated the trachea in almost all our patients, the success rate would be expected to be even higher when fully trained anesthesiologists manage the airway.
  • Neck circumference • Articoli che confermano l’importanza della circonferenza del collo: – The importance of increased neck circumference to intubation difficulties in obese patients Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O. The importance of increased neck circumference to intubation difficulties in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6, – Prediction of difficult laryngoscopy in obese patients by ultrasound quantification of anterior neck soft tissueT. Ezri, G. Gewürtz, D.I. Sessler, B. Medalion, P. Szmuk, C. Hagberg, and S.Susmallian.Anaesthesia. 2003 November ; 58(11): 1111–1114. • Anche nei bambini!!!(ma non intub difficulties) – high NC positively correlated with age and other anthropometric parameters – Children with high NC were more likely to be loud snorers and have a history of bronchial asthma, hypertension, and type 2 diabetes. – Composite adverse airway events were more frequent in children with a large NC – Pediatrics. 2011 Apr 4. [Epub ahead of print],Association of Neck Circumference With Perioperative Adverse Respiratory Events in Children.Nafiu OO, Burke CC, Gupta R, Christensen R, Reynolds PI, Malviya S. •
  • Pediatric obesity : a chi è interessato raccomando … • Anesthetizing the obese child. • Mortensen A, Lenz K, Abildstrøm H, Lauritsen TL. Chest. 2011 Mar 17. [Epub ahead of print] • Department of Anesthesiology, Juliane Marie Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark Department of Anesthesia, Center of Head and Orthopedics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. • Abstract • The prevalence of childhood obesity is increasing. The focus of this review is the special anesthetic considerations regarding the perioperative management of obese children. With obesity the risk of comorbidity such as asthma, obstructive sleep apnea, hypertension, and diabetes increases. The obese child has an increased risk of perioperative complications especially related to airway management and ventilation. There is a significantly increased risk of difficult mask ventilation and perioperative desaturation. Furthermore, obesity has an impact on the pharmacokinetics of most anesthetic drugs. This has important implications on how to estimate the optimal drug dose. This article offers a review of the literature on definition, prevalence and the pathophysiology of childhood obesity and provides suggestions on preanesthetic evaluation, airway management and dosage of the anesthetic drugs in these patients. The authors highlight the need of supplemental studies on various areas of the subject • More adverse periop events in obese children!!! – Br J Anaesth. 2011 Mar;106(3):359-63. Epub 2010 Dec 10..Incidence of perioperative adverse events in obese children undergoing elective general surgery.El-Metainy S, Ghoneim T, Aridae E, Abdel Wahab M.
  • T. Ezri, G. Gewürtz, D.I. Sessler, B. Medalion, P. Szmuk, C. Hagberg, S.Susmallian Anaesthesia. 2003 November ; 58(11): 1111–1114. • Prediction of difficult laryngoscopy in obese patients by ultrasound quantification of anterior neck soft tissue • The distance from the skin to the anterior aspect of the trachea was measured at three levels: • vocal cords (zone 1 – Fig. 1) • thyroid isthmus (zone 2) • suprasternal notch (zone 3) •
  • T. Ezri, G. Gewürtz, D.I. Sessler, B. Medalion, P. Szmuk, C. Hagberg, and S.Susmallian. Prediction of difficult laryngoscopy in obese patients by ultrasound quantification of anterior neck soft tissue.Anaesthesia. 2003 November ; 58(11): 1111–1114. • There were 9 cases (18%) of difficult laryngoscopy. • 7/9 patients with difficult laryngoscopy had a history of obstructive sleep apnoea whereas only 2/41 patients with easy laryngoscopy did (P < 0.001). Patients with difficult laryngoscopy had a larger neck circumference [50 (3.8) cm] than patients with easy laryngoscopy [43.5 (2.2) cm]; P < 0.001). • The difficult laryngoscopy patients also had much more soft tissue in zone 1 [(28 (2.7) mm] than did patients with easy laryngoscopy [17.5 (1.8) mm, P < 0.001 - Fig. 2], as well as in zone 3 [33(4.3) vs 27.4 (6.6), P < 0.013]. • Zone 1 soft tissue appears to be the best predictor of a difficult laryngoscopy. The range of zone 1 soft tissue for those with difficult laryngoscopy (24–32 mm) was mutually exclusive from those patients with an easy laryngoscopy (15–22 mm); hence, the zone 1 soft tissue values completely separated the difficult and easy laryngoscopies (Fig. 2). In contrast, the range for neck circumference had some overlap for those with difficult (45–57 cm) and easy (38–48 cm) laryngoscopy.
  • . Ezri, G. Gewürtz, D.I. Sessler, B. Medalion, P. Szmuk, C. Hagberg, and S.Susmallian. Prediction of difficult laryngoscopy in obese patients by ultrasound quantification of anterior neck soft tissue.Anaesthesia. 2003 November ; 58(11): 1111–1114.
  • Conclusioni di Ezri e coll: • Difficult laringoscopy associated with: • history of obstructive sleep apnoea • larger neck circumference [50 (3.8) cm] than patients with easy laryngoscopy [43.5 (2.2) cm). • much more soft tissue in zone 1 [(28 (2.7) mm] than did patients with easy laryngoscopy [17.5 (1.8) mm, as well as in zone 3 [33(4.3) vs 27.4 (6.6) • Zone 1 soft tissue appears to be the best predictor of a difficult laryngoscopy. • The range of zone 1 soft tissue for those with difficult laryngoscopy (24–32 mm) was mutually exclusive from those patients with an easy laryngoscopy (15–22 mm); hence, the zone 1 soft tissue values completely separated the difficult and easy laryngoscopies (Fig. 2). • In contrast, the range for neck circumference had some overlap for those with difficult (45–57 cm) and easy (38–48 cm) laryngoscopy.
  • Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O. The importance of increased neck circumference to intubation difficulties in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6, • • • • • • • • • • Department of Anesthesiology and Intensive Care, University Hospital of Toulouse, Toulouse, France. Abstract BACKGROUND: Using the intubation difficulty scale (IDS), we sought to confirm that obese patients are more difficult to intubate than lean patients. We assessed classical bedside tests and included neck circumference. METHODS: We prospectively compared the incidence of difficult tracheal intubation in 70 obese [body mass index (BMI) > or = 30 kg/m(2)] and 61 lean patients (BMI < 30 kg/m(2)). The IDS scores, categorized as difficult intubation (IDS > 5) or not (IDS < or = 5), and the patient data, were compared between lean and obese patients. Preoperative measurements [BMI, neck circumference (at the level of the thyroid cartilage), width of mouth opening, sternomental distance, and thyromental distance], medical history of obstructive sleep apnea syndrome, and several scores (Mallampati, Wilson, El Ganzouri) were recorded. The view during direct laryngoscopy was graded, and the IDS was recorded. We then compared patients with IDS < or = 5 and > 5, concerning each item. RESULTS: The results indicate that difficult tracheal intubation is more frequent in obese than in lean patients (14.3% vs 3%; P = 0.03). In the patients with IDS > 5, thyromental distance, BMI, large neck circumference, and higher Mallampati score were the only predictors of potential intubation problems. CONCLUSION: We found that problematic intubation was associated with thyromental distance, increasing neck circumference, BMI, and a Mallampati score of > or = 3. Neck circumference should be assessed preoperatively to predict difficult intubation
  • Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O. The importance of increased neck circumference to intubation difficulties in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6,
  • Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O. The importance of increased neck circumference to intubation difficulties in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6,
  • Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O. The importance of increased neck circumference to intubation difficulties in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6, Wilson score:simple summation of : The distance from the thyroid notch to the mentum (thyromental distance), the distance from the upper border of the manubrium sterni to the mentum (sternomental distance),
  • Wilson score
  • Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O. The importance of increased neck circumference to intubation difficulties in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6, • Among the potential predictors we evaluated, thyromental distance, BMI, neck circumference, and a Mallampati score >3 were the only useful bedside test predictors of difficult intubation. • Our results thus confirm the work of Brodsky et al.5 who showed that neck circumference at the thyroid cartilage is a valuable predictor of difficult aryngoscopy in obese patients. Interestingly, all other putative predictors were similar in the two populations. Moreover, neck circumference also seems to be a predictive test in lean patients. Circumference does not indicate the amount of soft tissue at various topographic regions within the neck. Distribution of fat in specific neck areas, especially the anterior neck, may provide a better indication of difficult intubation than neck circumference. By using magnetic resonance imaging measurements in obese patients with and without OSA syndrome, Horner et al. demonstrated that more fat was present in areas surrounding the collapsible segments of the pharynx in patients with OSA syndrome.24 This may explain why some obese patients are easy to
  • True pos,neg pos,false pos,false neg • • • • • • • • True positive a difficult intubation that had been predicted to be difficult. False positive an easy intubation that had been predicted to be difficult. True negative an easy intubation that had been predicted to be easy. False negative a difficult intubation that had been predicted to be easy. Sensitivity the percentage of correctly predicted difficult intubations as a proportion of all intubations that were truly difficult, i.e.:True positives/(true positives +false negatives) Specificity the percentage of correctly predicted easy intubations as a proportion of all intubations that were truly easy, i.e.: True negatives/(true negatives +false positives) Positive predictive value the percentage of correctly predicted difficult intubations as a proportion of all predicted difficult intubations, i.e.: True positives/(true positives f+alse positives) Negative predictive value the percentage of correctly predicted easy intubations as a roportion of all predicted easy intubations, i.e.: True negatives/(true negatives +false negatives)
  • Does neck circumference predict difficult laryngoscopy in morbidly obese patients? H. Abrahams, C. Bygrave, C. Doyle, A. Kendall, M. Margarson • • • • • • • 19AP2-5 Department of Anaesthesiology and Intensive Care, St Richard’s Hospital, Chichester, United Kingdom Background and Goal of Study: Morbidly obese patients are reported to be more difficult to intubate than the general population. The single greatest predictor of difficult intubation is suggested to be a neck circumference of ≥50cm, this is based on a study of 100 patients1. For the past three years we have entered neck circumference data onto our anaesthetic database and have analysed it to confirm or refute this assertion. Materials and Methods: Between January 2008 and December 2009, 836 Morbidly Obese patients (149 with BMI >60 kg/m2) underwent Roux-en-Y Gastric Bypass or Gastric Banding at our Bariatric Unit. All patients were seen pre-operatively in a multi-disciplinary outpatient clinic where demographic data including neck measurement and Mallampati score were recorded. On the day of surgery the grade of laryngoscopy, according to the classification of Cormack and Lehane, was recorded. Notes were reviewed and data entered onto the database. Analysis of Variance between the patients grouped by grade of laryngoscopy was performed using the Kruskal-Wallis test. Results and Discussion: Full data was available on 503 patients (126 male, 25%) with a median age of 44 years (range 17-73). The median BMI was 51kg/m2 (range 32-100) and the median weight was 143 kg (range 89-289 kg). ANOVA demonstrated a highly significant difference between the median values. (p<0.0001) The overall incidence of Cormack & Lehane Grade 3 or 4 Laryngoscopy was 6.6%. In the 91 patients with a neck circumference ≥50cm the incidence was 21%. Cormack + Lehane Grade 1 2a 2b 3 or 4Median Neck Circumference (cm) 43 45 46 50.5Interquartile range 41 - 47 42 - 49 43 - 50.3 43.8 - 58 Conclusion(s): There is a clear and stepwise correlation between difficult laryngoscopy and neck circumference in these patients. The overall incidence of difficult laryngoscopy is not high, but a neck circumference ≥50cm does appear to be a strong predictor.
  • Does neck circumference predict difficult laryngoscopy in morbidly obese patients? H. Abrahams, C. Bygrave, C. Doyle, A. Kendall, M. Margarson There is a clear and stepwise correlation between difficult laryngoscopy and neck circumference in these patients. The overall incidence of difficult laryngoscopy is not high, but a neck circumference ≥50cm does appear to be a strong predictor.
  • Ann Otol Rhinol Laryngol. 2007 Nov;116(11):799-804. Prediction of difficult laryngoscopy: does obesity play a role? Hekiert AM, Mick R, Mirza N • • . Source • Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania • • • • • • Medical Center, 3400 Spruce St, 5th Floor Ravdin Bldg, Philadelphia, PA 19104, USA. Abstract OBJECTIVES: This study was intended to 1) identify preoperative predictors of difficult laryngoscopy and 2) determine the role of obesity in difficulty of obtaining adequate laryngeal exposure. METHODS: A prospective study was undertaken of 63 patients who were undergoing elective direct laryngoscopy. Thirty-six patients met the obesity criteria (body mass index of at least 30 kg/m2). Measurements of height, weight, and neck circumference and Mallampati and Cormack-Lehane scores were obtained. The ease of laryngeal exposure was recorded by the attending surgeon on a visual analog scale (VAS; 1 to 10). Difficult laryngeal exposure (DLE) was defined as a VAS score of at least 3. The candidate morphological predictors were investigated. RESULTS: • Obesity and Mallampati score were found to be predictors of DLE (p < .001). The VAS score was • • positively correlated with body mass index (p = .007), weight (p = .05), Mallampati score (p < .001), and CormackLehane score (p < .001). Among obese patients, the VAS score was correlated with the Cormack-Lehane score (p = .01), whereas in nonobese patients the VAS score showed a significant association with both the Mallampati (p = .02) and Cormack-Lehane (p = .01) scores. CONCLUSIONS: Obese patients and those with a Mallampati score of at least 2 posed a significantly higher risk of DLE. Preoperative identification of a potentially difficult airway may aid surgical planning and allow more effective communication with a collaborating anesthesiologist
  • Hekiert, A., Mick, R., & Mirza, N. (2007). Prediction of difficult laryngoscopy: does obesity play a role? Annals of otology, rhinology & laryngology, 116(11), 799-804. • Unfortunately there was data missing from 30 patients in this study. The missing data was the Cormack Lehane grades. Given this gross mishap in their data collection this author has excluded any results pertaining to the laryngoscopic view as reliability and validity of those results is questionable… • Una volta che ci potevano dare una mano……………..
  • Obes Surg. 2010 Oct;20(10):1436-41. An evaluation of the rapid airway management positioner in obese patients undergoing gastric bypass or laparoscopic gastric banding surgery. Cattano D, Melnikov V, Khalil Y, Sridhar S, Hagberg CA. • • Source Department of Anesthesiology, The University of Texas Medical School at Houston, 6431 Fannin, MSB 5.020, Houston, TX 77030, USA. • 51 obese BMI>35 for bariatric surgery • Ease of Ventilation and laryngoscopy was performed in the neutral and headelevated laryngoscopy position (HELP). (Rapid Airway Management Positioner (RAMP, Airpal Inc., Center Valley, PA) • Direct laryngoscopy was performed noting the glottic view according to the Cormack-Lehane classification (Samsoon and Young, Anesthesiology 42:487, 1987). Mask ventilation was then recommenced. • Once proper HELP position was achieved, a second laryngoscopy was performed followed by endotracheal intubation. • The inflated ramped position provided greater ease of ventilation as compared to the neutral position (p = 0.0003). • There was also a significant improvement in the glottic view in the ramped position (p = 0.04) • The RAMP effectively positions morbidly obese patients in the HELP position. Ease of ventilation and laryngoscopic view were both improved with its use in this patient population
  • J Clin Anesth. 2009 Jun;21(4):264-7. Epub 2009 Jun 6. Predicting difficult airways using the intubation difficulty scale: a study comparing obese and non-obese patients. Lavi R, Segal D, Ziser A. • • • • • • • To compare intubation difficulty in obese and non-obese patients by intubation difficulty scale (IDS), intubation duration measurement, and oxygen saturation (SaO(2)) levels. 204 ASA physical status I, II, and III adult patients who underwent elective surgery with endotracheal intubation. Preoperative airway parameters, intubation duration, IDS scores, and lowest SaO(2) during intubation were recorded. MAIN RESULTS: IDS scores were higher in the obese group than the non-obese (2.29 +/- 0.45 and 1.26 +/- 0.2, respectively, P = 0.03). Intubation duration was 45.1 +/- 6 sec for obese versus 36.8 +/- 2.6 sec for the non-obese group (P = 0.20). The lowest SaO(2) recorded was 97%, with no difference noted between groups. Mallampati class >or=3 was found to positively predict intubation difficulty scores greater than 5. CONCLUSIONS: Difficult intubation was more prevalent among obese than non-obese patients, but intubation duration and lowest SaO(2) levels during intubation were not. Moreover, • the modified Mallampati test was found to be a moderately good (60%) predictor of difficult intubation among obese patients • sniffing position. All laryngoscopies were performed using a size 3 Macintosh blade, and the trachea was intubated with a cuffed endotracheal tube. An intubation stylet was not used routinely
  • The IDS N 5 group had the highest BMI, although some overlap existed between the groups. Lavi R, Segal D, Ziser A. Predicting difficult airways using the intubation difficulty scale: a study comparing obese and non-obese patients. J Clin Anesth. 2009 Jun;21(4):264-7.
  • Intubation difficulty scale (IDS) scores and intubation duration among obese and non-obese patients. The IDS score was significantly higher in obese patients, but intubation duration did not differ significantly between the groups
  • Rao SL, Kunselman AR Schule HG, DesHarnais S.Laryngoscopy and Tracheal Intubation in the Head-Elevated Position in Obese Patients: A Randomized, Controlled, Equivalence Trial..Anesth Analg 2008;107:1912–8 • BACKGROUND: The proper positioning of patients before direct laryngoscopy is a key step that facilitates tracheal intubation. In obese patients, the 25 degree back-up or head-elevated laryngoscopic position, which is better than the supine position for tracheal intubation, is usually achieved by placing blankets or other devices under the patient’s head and shoulders. This position can also be achieved by reconfiguring the normally flat operating room (OR) table by flexing the table at the trunk-thigh hinge and raising the back (trunk) portion of the table (OR table ramp). This table-rampmethod can be used without the added expense of positioning devices, and it reduces the possibility of injury to the patient or providers that can occur during removal of such devices once tracheal intubation is achieved. • In this study, we sought to determine if the table-ramp method of patient positioning was equivalent to the blanket method with regard to the time required for tracheal intubation. 85 adults with a Body Mass Index> 30 kg/m2, scheduled for elective surgery, prospective randomized equivalence study conducted in a teaching hospital randomization scheme used permuted blocks with subjects equally allocated to be positioned using either the blanket method or the table-ramp method. end-point in either case : head-elevated position, where the patient’s external auditory meatus and sternal notch were in the same horizontal plane all patients were positioned by the same anesthesiologist, laryngoscopy and tracheal intubation were performed by trainees with various levels of expertise. Standard IV induction and tracheal intubation techniques were used. The time from loss of consciousness to the time after tracheal intubation when end-tidal CO2 was detected was recorded. The effectiveness of mask ventilation and quality of laryngeal exposure were also noted. RESULTS: The mean time (sd) to tracheal intubation was 175 (66) s in the blanket group, as compared to 163 (71) s in the table-ramp group. Assuming the bounds for equivalence are 55,55 s, our study found a 95% confidence interval of 36.22,13.52 s using two one-sided tests for equivalence corresponding to a significance level of 0.05. There was no difference in the number of attempts at laryngoscopy (P 0.21) and tracheal intubation (P 0.76) required to secure the airway between the two groups. CONCLUSIONS: Before induction of anesthesia, obese patients can be positioned with their head elevated above their shoulders on the operating table, on a ramp created by placing blankets under their upper body or by reconfiguring the OR table. For the purpose of direct laryngoscopy and tracheal intubation, these two methods are equivalent. () • • • • • • • • • • •
  • Outcome variables in the study by Rao et al.
  • Time required to secure the airway(from LOC to etCO2 detection Rao SL, Kunselman AR Schule HG, DesHarnais S.Laryngoscopy and Tracheal Intubation in the Head-Elevated Position in ) Obese Patients: A Randomized,Controlled, Equivalence Trial..Anesth Analg 2008;107:1912–8
  • Conclusions from Rao et al ;the 2 positions RAMP with blankets or with ORtable are equivalent for the purpose of tracheal intubation,but………. • It is easier with the electronic controls of the OR table to recreate a table ramp during emergence instead of reinserting blankets under the patient. • Surgeons prefer not to have blankets under the anesthetized patient during surgery • As a larger portion of the patient’s back is in contact with the operating table surface when blankets are not used to position patients, the likelihood of injury to the patient’s skin is minimized when blankets are removed after tracheal intubation. However, injury to OR personnel may occur when an attempt is made to • lift or move patients so that the blankets can be removed from under the patients after tracheal intubation. • Use of the electronic controls of the OR table to position patients avoids these problems.
  • Conclusion about intubation difficulty(es) with obese patients: • The evidence is contradictory,but • Difficult laryngoscopy is not sinonimous with difficult intubation • Large neck (and especially fat accumulated anteriorly at the level of the vocal cords)and Mallampati 3 & 4 are associated with difficulties;+diabetes and superobese(BMI>60); • Awake FOB intubation!
  • Conclusions 2 • (Partly I wonder whether this is due to a greater degree of vigilance and better preparation/positioning than for the non-obese patient.) • • BMI per se is not a factor of difficulty Sleep apnea is not a factor for difficulty • Patient must be positioned in the ramped position(or 30 degree anti trendelemburg+ slight ramped) • Look always for anatomical factors for difficult intubation combination of tests > single test : • Mallampati with forced tongue and neck extension – Restricted flexion and extension of the neck and atlantooccipital joint – because of numerous chins and low cervical and upper thoracic fat pads/large breasts. – Mouth opening can be limited by submental fat. – Airway may be narrowed by fleshy cheeks, a large tongue and copious pads of palatal, pharyngeal and supralaryngeal soft tissues. – A high anterior and infantile laryngeal position may be presentT
  • Conclusion 3:POGO score La RAMP position deve sempre essere usata per facilitare la visione glottica e la intubazione: Collins JS, Lemmens HJ, Brodsky JB, Brock-Utne JG, Levitan RM. Laryngoscopy and morbid obesity: a comparison of the "sniff' and "ramped" positions. Obes Surg 2004;14:1–5 Questo è vero anche in pazienti normali! Lee BJ, Kang JM, Kim DO. Laryngeal exposure during laryngoscopy is better in the 25 degrees back-up position than in the supine position . Br J Anaesth 2007;99:581–6
  • Lee BJ, Kang JM, Kim DO. Laryngeal exposure during laryngoscopy is better in the 25 degrees back-up position than in the supine position . Br J Anaesth 2007;99:581–6 • • • • Laryngoscopy with a curved blade was performed on 40 anaesthetized patients. The patients were randomly assigned to two groups. Laryngeal views were captured with a rigid Olympus endoscope. Views were recorded for each patient in Group A (n¼20) during laryngoscopies performed with the patient lying first in the supine position and then in the 258 back-up position. Laryngeal views for patients in Group B (n¼20) were first captured while the patient was in the 258 back-up position and then while the patient was in the flat supine position. An anaesthetist blinded to the position graded the quality of the images using the percentage of glottic opening (POGO) score. • Results. Comparing the two positions, mean (SD) POGO scores increased significantly from 42.2 (27.4)% in supine position to 66.8 (27.6)% in 25 o back-up position (P,0.0001). • Conclusions. During laryngoscopy, the laryngeal view, as assessed by POGO scores, improves significantly in the 258 back-up position when compared with the flat supine position.
  • POGO score:percentage of glottic opening
  • POGO scores increased significantly from 42.2 (27.4)% in supine position to 66.8 (27.6)% in 25 o back-up position. Lee BJ, Kang JM, Kim DO. Laryngeal exposure during laryngoscopy is better in the 25 degrees back-up position than in the supine position . Br J Anaesth 2007;99:581–6
  • A 45o direction to lift the handle of the laryngoscope in the supine-horizontal position decreases to about 20o in the 25o back-up position (Fig. 4). A change of direction to lift the handle leads to a change of force and torque. Vertical force against gravity will be decreased and horizontal force increased in the back-up position. In the back-up position, a laryngoscopist can push the blade of the laryngoscope forward rather than upward with the same force and get an improved view of the larynx.
  • • • • • Figure 5 shows that the anterior movement of laryngeal structures caused by anaesthesia and head extension displaces the LA, defined as a straight line passing through the centres of the inferior (cricoid cartilage) and superior (base of epiglottis) orifices vertically without modification of the angle. In contrast, the line of vision (LV), defined as a straight line passing through theinferior extremity of the superior incisors and the posterior extremity of the superior portion of the cricoid cartilage is slightly affected by this change and thus, a slight decrease in the angle between LA and LV can be expected.11 In the 25o back-up position, laryngeal structures move a little more caudally by the gravity than in the supine position and the angle between LA and LV can be further decreased. The gravitational force may pull the laryngeal structures caudally directly and indirectly by pulling whole structure of upper thorax connected to the laryngeal structures. In the paralysed patients, the muscle tone to support the laryngeal structures will be lessened and the effect of gravity will be even more than that seen in awake and unparalysed patients. Thus, the change of effects of gravitational force in the caudal direction cannot be neglected.
  • Time limits,emergencies,poor positioning could be factors for difficult intubation in obese patients • Levitan RM, Everett WW, Ochroch EA. Limitations of difficult airway prediction in patients intubated in the emergency department. Ann Emerg Med 2004;44:307–13 • Levitan RM, Chudnofsky C, Sapre N. Emergency airway management in a morbidly obese, noncooperative, rapidly deteriorating patient. Am J Emerg Med 2006;24:894–6
  • Prone position?? • For the prone position one should consider awake intubation. Then the patient can position him or herself.. • The Lateral Decubitus position is sometimes used as a substitute for the prone position. • It should be taken as a positive that few reports are in the literature of problems placing obese patients in this position. Morbidly obese patients seem to tolerate this position well. Brodsky et al. (Anesthesiology 57:132, 1982) found that oxygenation during thoracotomy in the LDP and one-lung ventilation (FIO2 1.0) was satisfactory.
  • Attenzione allo scivolamento!!!! • Fermare opportunamente il paziente;straps,velcro,fasce,ecc.
  • Infine…non dimentichiamoci della estubazione!!! • Massima attenzione anche alla estubazione! • “the majority (19 of 26) of the claims from extubation or recovery were associated with a difficult intubation on induction, obesity, and/or sleep apnea”(ASA closed claims 2006) • Quindi,prima di svegliare: • Preossigenazione • Recruitment +PEEP o NIV • Inserimento di una guida se l’intubazione è stata difficile.. • Altro???suggerimenti??
  • INTUBATION OF THE OBESE IN THE ICU
  • SOLUZIONI PER INTUBAZIONE:ILMA
  • ILMA
  • The Mallinckrodt PVC tracheal tube’s (7.0-mm internal diameter) natural bend was oriented in two different ways when inserting it in the intubating LMA. As a result, the angle that the tip of the tracheal tube emerged from the intubating LMA was 47° or 20°, respectively. Tao Zhu.Conventional Endotracheal Tubes for Intubation Through the Intubating Laryngeal Mask Airway.Anesth. Analg. January 1, 2007 104:213-214
  • The angle of 20° increases to 40° when mild force is applied or the tip encounters resistance during tracheal intubation Tao Zhu.Conventional Endotracheal Tubes for Intubation Through the Intubating Laryngeal Mask Airway.Anesth. Analg. January 1, 2007 104:213-214
  • Tao Zhu.Conventional Endotracheal Tubes for Intubation Through the Intubating Laryngeal Mask Airway.Anesth. Analg. January 1, 2007 104:213-214 • Our study revealed that the 20° angle was associated with more frequent success for endotracheal intubation (90%) than the 47° angle (84%). It also resulted in less frequent sore throat (19% vs 26%, respectively; Table 1). The overall success rate with our method is about 87% in patients with or without difficult airway. Our experience indicates that the Mallinckrodt PVC tracheal tube can be used as successfully as the Rusch PVC tracheal tube for blind tracheal intubation through the intubating LMA (1).
  • LMA CTrach LMA CTrachTM (CT), a modified version of the intubating LMA FastrachTM, allows continuous videoendoscopy of the tracheal intubation procedure.
  • Combes X, Sauvat S, Leroux B, et al. Intubating laryngeal mask airway in morbidly obese and lean patients: a comparative study. Anesthesiology. 2005;102(6):1106–1109 We demonstrated that the safety and efficiency of the ILMA were comparable between lean and obese patients, but according to quality criteria, airway management was simpler in obese as compared with lean patients
  • • metal handle may be the result of better spontaneous pharyngeal placement of the mask because of the reduced pharyngeal caliber that can be observed in obese patients. Magnetic resonance imaging has shown a decreased pharyngeal area and volume in obesity associated with the deposition of adipose tissue, predominantly in the lateral pharyngeal walls.23,24 These lateral fat columns might serve to guide or railroad the ILMA into place during its descent into the pharynx and stabilize its position after cuff inflation. This hypothesis may explain why a sealed airway was more frequently obtained in obese patients as compared with lean patients. • However, Archie Brain, M.D. (personal verbal communication, 46e Congrès de la Socie´te´ Franc¸aise d’Anesthe´sie et Re´animation, Club Respiratoire, Paris, France, September 2004), noted that in normal patients, with the ILMA as opposed to the standard laryngeal mask airway, the narrow convex posterior part of the ILMA, combined with the rigidity of its airway tube, seemed to cause the mask to slip more easily to one side or the other of the oppositely curved midline cervical bodies. He suggested that this tendency might be a factor causing occasional misalignment of the mask with the laryngeal aperture. We believe that these observations may account for our higher incidence of airway-adjustment maneuvers and failed blind intubation attempts in lean patients, resulting in longer and more difficult airway management in some of these patients.
  • Frappier J, Guenoun T, Journois D, Philippe H, Aka E, Cadi P, Silleran-Chassany J.Airway management using the intubating laryngeal mask airway for the morbidly obese patient. Anesth Analg. 2003 ;96(5):1510-5 success rate of successful tracheal intubation with ILMA was 96.3%. Attempt number and total duration of the procedure were not different among patients with low-grade (Cormack 1-2) and patients with high-grade (Cormack 3-4) laryngeal views. The time required for insertion of the ILMA was slightly longer in patients with high-grade laryngeal views The level of clinician experience for this technique does not seem to influence either the mean duration or the number of attempts required to achieve adequate ventilation or tracheal intubation. Thus, airway management with the ILMA is easily achieved, even by inexperienced practitioners in obese patients in whom difficult mask ventilation and tracheal intubation is common
  • ILMA in obese and out of hospital • . • • Combes X, Leroux B, Jabre P, Margenet A, Dhonneur G.Out-of-hospital rescue oxygenation and tracheal intubation with the intubating laryngeal mask airway in a morbidly obese patient. Ann Emerg Med. 2004 Jan;43(1):140-1 . • Lavoro tedesco ………….
  • Wender R, Goldman. . AJ.Awake insertion of the fibreoptic intubating LMA CTrach in three morbidly obese patients with potentially difficult airways.Anaesthesia. 2007 Sep;62(9):948-51 • ILMA,+ integrated fibreoptic bundle that provides a view of the larynx. • This enables visualisation of tracheal intubation while delivering 100% oxygen, with or without an inhalational anaesthetic • We report awake insertion of the CTrach in three morbidly obese patients (BMI 60-63) with known or anticipated difficult airways. • midazolam + glycopyrrolate i.v. • topical lidocaine 4%. • CTrach was inserted into the oropharynx of the still-awake patient • the vocal cords were visualised • anaesthetic induction was commenced with sevoflurane and spontaneous ventilation • we were able to see the vocal cords during the entire anaesthetic induction and intubation • Patients very satisfied
  • Dhonneur G, Ndoko SK, Yavchitz A, Foucrier A, Fessenmeyer C, Pollian C, Combes X, Tual L.Tracheal intubation of morbidly obese patients: LMA CTrach vs direct laryngoscopy.Br J Anaesth. 2006 Nov;97(5):742-5. • • • • • • • • LMA CTrach (CT), a modified version of the intubating LMA Fastrach, allows continuous video-endoscopy of the tracheal intubation procedure. We tested the hypothesis that the CT is efficient for tracheal intubation of morbidly obese patients who are at risk of a difficult airway. METHODS: After Ethics' Committee approval, 104 morbidly obese patients (BMI >35 kg m(-2)) scheduled for bariatric surgery were included in this prospective study. Patients were randomly assigned in two groups: tracheal intubation using direct laryngoscopy (DL) or the CT. Induction of anaesthesia was standardized using sufentanil, propofol and succinylcholine. Characteristics and consequences of airway management were evaluated. RESULTS: Preoperative characteristics of patients and consequences of anaesthesia induction on physiological variables were similar in both groups. Difficulty in facemask ventilation was similar in both groups. Tracheal intubation was successfully carried out with DL and CT. Forty-nine per cent of the patients from the CT group required laryngeal mask manipulation (ventilation and view optimization) resulting in increased duration of tracheal intubation by 57 s as compared with DL. Oxygenation was of better quality in the patients managed with CT than with DL. Blind tracheal intubation was mandatory in eight (17%) patients of the DL group, while tracheal intubation was seen in all patients of the CT group. CONCLUSION: We demonstrated in morbidly obese patients that trachealintubation performance of the CT was superior to that of DLbecause it allowed systematic visualization of the tracheal intubation. This promoted better oxygenation during the procedure. In comparison with previous data obtained in morbidly obese patients using ILMA our results with CT suggest that additional visualization of laryngeal structure allowed optimization of placement of the mask in the pharynx. This results in reduced tracheal intubation attempts and a 100% tracheal intubation success rate. Such a high success rate for visualized tracheal intubation was not systematically obtained with CT in recent studies.
  • Dhonneur G, Ndoko SK, Yavchitz A, Foucrier A, Fessenmeyer C, Pollian C, Combes X, Tual L.Tracheal intubation of morbidly obese patients: LMA CTrach vs direct laryngoscopy.Br J Anaesth. 2006 Nov;97(5):742-5.
  • Airway management data with the LMA Ctrach Dhonneur G, Ndoko SK, Yavchitz A, Foucrier A, Fessenmeyer C, Pollian C, Combes X, Tual L.Tracheal intubation of morbidly obese patients: LMA CTrach vs direct laryngoscopy.Br J Anaesth. 2006 Nov;97(5):742-5.
  • Dhonneur G, Ndoko SK, Yavchitz A, Foucrier A, Fessenmeyer C, Pollian C, Combes X, Tual L.Tracheal intubation of morbidly obese patients: LMA CTrach vs direct laryngoscopy.Br J Anaesth. 2006 Nov;97(5):742-5. • Three manoeuvres applied with the metal handle and performed with the cuff remaining inflated, derived from those described by the inventor of ILMA1 were used to resolve ventilation problems and unsatisfactory visualization: • Chandi, down–up–down (DUD): the laryngeal mask is blocked distal in the pharynx, then it is removed by approximately 3–6 cm and replaced more distal) • medial– lateral–medial (MLM): smooth lateralization of the laryngeal mask in the pharynx in which depth of insertion does not vary). • With glottis view optimized, a reinforced flexible tracheal tube was inserted through the airway tube and railroaded in the trachea. In case of impossible glottisvisualization after two insertions or in case of impossible intubation with the CT correctly placed, DL was proposed.
  • Table :Success rate of intubation through direct visualization with the LMA C trach author Success rate Notes: Dhonneur BJA 2006 100% Manipulation 31% Timmermann BJA 2006 92 Manipulation 63% Timmermann Anesthesist 2006 84 Journal Not found Freid AnesthClin N.Am 2005 80 Review article Timmermann A, Russo S, Graf BM. Evaluation of the CTrachTM— an intubating LMA with integrated fibreoptic system. Br J Anaesth 2006; 96: 516–21 Timmermann A, Russo S, Natge U, Heuer J, Graf BM. LMA CTrachTM: Initial experiences in patients with difficult-to-manage airways. Anaesthesist 2006; 55: 528–34 Freid EB. The rapid sequence induction revisited: obesity and sleep apnea syndrome. Anesthesiol Clin North America 2005; 23: 551–64
  • VIDEOLARYNGOSCOPY:AIRTRAQ,RU SCH,……
  • Airtraq
  • Obesity Surgery Volume 19, Number 8, 1096-1101 Video-Assisted Versus Conventional Tracheal Intubation in Morbidly Obese Patients . Dhonneur G, Abdi W, Ndoko SK, Amathieu R, Risk N, El Housseini L, Polliand C, Champault G, Combes X, Tual L. • Anesthesiology and Intensive Care Medicine Department, Jean Verdier Public University Hospital of Paris (APHP), 93143, Bondy, France. gilles.dhonneur@jvr.aphp.fr • tracheal intubation characteristics and arterial oxygenation quality during airway management of morbidly obese patients whose trachea was intubated under video assistance with the LMA CTrach (SEBAC, Pantin, France) or the Airtraq laryngoscope (VYGON, Ecouen, France) with that of the conventional Macintosh laryngoscope. After standardized induction of anesthesia, 318 morbidly obese patients scheduled for elective morbid obesity surgery received tracheal intubation with the LMA CTrach, the Airtraq laryngoscope, or the conventional Macintosh laryngoscope Duration of apnea, time to tracheal intubation, and oxygenation quality during airway management were compared between the LMA CTrach and the laryngoscope groups. The success rate for tracheal intubation was 100% with the LMA CTrach and the Airtraq laryngoscope. One patient of the Macintosh laryngoscope group received LMA CTrach intubation because of early arterial oxygen desaturation associated with unstable facemask ventilation. The duration of apnea was shorter with the LMA CTrach than that of the Airtraq laryngoscope and the Macintosh laryngoscope. The duration tracheal intubation was shorter with the Airtraq laryngoscope than with the Macintosh laryngoscopes and the LMA CTrach. During airway management, arterial oxygenation was of better quality with the LMA CTrach and the Airtraq laryngoscope than that of the Macintosh laryngoscope. CONCLUSION: Because LMA CTrach promoted short apnea time and the Airtraq laryngoscope allowed early definitive airway, both video-assisted tracheal intubation devices prevented most serious arterial oxygenation desaturation evidenced during tracheal intubation of morbidly obese patients with the conventional Macintosh laryngoscope • • • • • • •
  • European Journal of Anaesthesiology 2007; 24: 1045–1049 Videolaryngoscopy improves intubation condition in morbidly obese patients.J. Marrel, C. Blanc, P. Frascarolo, L. Magnusson • • • • • • • • • • The videolaryngoscope used was a Ru¨sch videolaryngoscope (X-Lite Videolaryngoscope, Ru¨ sch Medical, Germany) with the light source at the tip of the blade. The screen is mobile, as a laptop screen, 20 cm in diameter.. 80 morbidly obese patients undergoing bariatric surgery. randomly assigned to one of two groups:One group was intubated with the help of the videolaryngoscope and in the control group the screen of the videolaryngoscope was hidden to the intubating anaesthesiologist. The primary end-point of the study was to assess in both groups the Cormack and Lehane direct and indirect grades of laryngoscopy. The duration of intubation, the number of attempts needed as well as the minimal SPO2 reached during the intubation process were measured. Results: Grade of laryngoscopy was significantly lower with the videolaryngoscope compared with the direct vision (P,0.001). When the grade of laryngoscopy was higher than one with the direct laryngoscopy , it was lower in 28 cases with the videolaryngoscope and remained the same only in two cases (P,0.001). The minimal SPO2 reached during the intubation was higher with the videolaryngoscope but it did not reach statistical significance. The duration of intubation was significantly shorter with the videolaryngoscope than with direct view (59631 s (range: 30–208) vs. 93670 s (range:40–450)) (P50.006). The minimal SPO2 was 98.26 0.8% with the videolaryngoscope and 97.16 with direct view (P50.075). Conclusions: In morbidly obese patients, the use of the videolaryngoscope significantly improves the visualization of the larynx and thereby facilitates intubation.
  • Anesthesia technique of European Journal of Anaesthesiology 2007; 24: 1045–1049.Videolaryngoscopy improves intubation condition in morbidly obese patients.J. Marrel, C. Blanc, P. Frascarolo, L. Magnusson • no premedication • In the operating room, a special pillow was put under the patients’ shoulders in order to ramp up the patient’s shoulders, and the head and the neck was extended in a sniffing position. • 5 min. preoxygenation with 100% oxygen with a tight facemask was • performed. • Anaesthesia was then induced with propofol (1.5–2.5 mg/ kg followed by a continuous infusion of propofol at 4–6 mg/ kg/ h • and remifentanil at 0.25 microg /kg/ min • Patients received cisatracurium 0.2 mg/ kg to facilitate intubation. Muscle relaxation was evaluated with a nerve stimulator placed on the ulnar nerve. • When TOF response was 0, laryngoscopy was performed.
  • Ndoko SK, Amathieu R, Tual L, Polliand C, Kamoun W, El Housseini L, et al. Tracheal intubation of morbidly obese patients: a randomized trial comparing performance of Macintosh and Airtraq TM laryngoscopes. Br J Anaesth 2008;100:263-8 the AirtraqTM laryngoscope shortened the duration of tracheal intubation and prevented reductions in arterial oxygen saturation in morbidly obese patients
  • ANCHE LA PROSEAL FUNZIONA NEGLI OBESI….
  • Keller C, Brimacombe J, Kleinsasser A, Brimacombe L. The Laryngeal Mask Airway ProSeal(TM) as a temporary ventilatory device in grossly and morbidly obese patients before laryngoscope-guided tracheal intubation. Anesth Analg. 2002 Mar;94(3):737-40 • We determined the efficacy of the laryngeal mask airway ProSeal(TM) (PLMA) as a temporary ventilatory device in morbidly obese patients before laryngoscope-guided tracheal intubation. Sixty patients (body mass index 35--60 kg/m(2)) scheduled for elective surgery, who preferred airway management under general anesthesia, were studied. The induction of anesthesia was with midazolam/fentanyl/propofol and maintenance was with sevoflurane 1%--3% in oxygen 100%. The PLMA was inserted and an effective airway established. Rocuronium was given IV for paralysis. Oropharyngeal leak pressure, ease of gastric tube placement, residual gastric volume, fiberoptic position of the airway/drainage tube, and ease of ventilation at a tidal volume of 8 mL/kg was determined. The PLMA was then removed and laryngoscope-guided tracheal intubation attempted. The number of insertion/intubation attempts (maximum two each) and time taken to establish an effective airway with each device were recorded. An effective airway was obtained at the first insertion attempt in 90% of patients (54/60) and at the second attempt in 10% (6/60). The time taken to provide an effective airway was 15 plus minus 7 s (7-42 s). Oropharyngeal leak pressure was 32 plus minus 8 cm H(2)O (12--40 cm H(2)O). The residual gastric volume was 36 plus minus 46 mL (0--240 mL). Positive pressure ventilation without air leaks was possible in 95% of patients (57/60). The vocal cords were seen from the airway tube in 75% of patients (45/60), but the esophagus was not seen. The fiberoptic view from the drainage tube revealed mucosa in 93% of patients (56/60) and an open upper esophageal sphincter in 7% (4/60). Tracheal intubation was successful at the first attempt in 90% of patients (54/60), at the second attempt in 7% (4/60), and failed in 3% (2/60). In these latter two patients, the PLMA was reinserted and surgery performed uneventfully with the PLMA. The time taken to tracheally intubate the patient was 13 plus minus 10 s (8--51 s). There were no episodes of hypoxia (SpO(2) <90%) or other adverse events. There were no differences in insertion success rate, or the time to successful insertion between the PLMA and laryngoscope-guided intubation. We conclude that the PLMA is an effective temporary ventilatory device in grossly or morbidly obese patients before laryngoscope-guided tracheal intubation. IMPLICATIONS: The laryngeal mask airway ProSeal(TM) is an effective temporary ventilatory device in grossly and morbidly obese patients before laryngoscope-guided tracheal intubation
  • Keller C, Brimacombe J, Kleinsasser A, Brimacombe L. The Laryngeal Mask Airway ProSeal(TM) as a temporary ventilatory device in grossly and morbidly obese patients before laryngoscope-guided tracheal intubation. Anesth Analg. 2002 Mar;94(3):737-40 • • • • Anesthesia technique: Ranitidine per os 1.5 h preoperatively. Monitoring was applied before induction and included an electrocardiograph,pulse oximeter, gas analyzer, arterial line, tidal volume monitor, airway pressure monitor, and peripheral nerve stimulator. Anesthesia was given with the patient in the supine position with the patient’s head on a standard pillow 8 cm in height. • • • • • • Midazolam 0.02 mg/kg and fentanyl 1 microg/kg were administered. Patients were preoxygenated for 5 min. Anesthesia was induced with propofol 2–3 mg/kg given over 30 s, and the PLMA inserted when there was no response to jaw thrust (5). Additional boluses of propofol 0.5 mg/kg were given as required until an adequate level of anesthesia was achieved for placement. Anesthesia was maintained with sevoflurane 1%–3% in oxygen 100%. Face mask ventilation was performed if conditions for insertion were not suitable within 30 s of completion of the induction dose. The size 5 PLMA was inserted/fixed according to the manufacturer’s instructions
  • Conclusioni sui presidi alternativi • ILMA,C trach,Airtraq sono superiori alla laringoscopia diretta negli obesi ! • facilitano la intubazione con maggiore sicurezza perché permettono la ossigenazione durante le manovre • Meglio acquisire esperienza con questi devices!!! • (ma è importante il training…..)
  • AWAKE INTUBATION
  • Pro/cons awake intubation advantages awake Asleep breathing Asleep not breathing Airway tone maintained yes No No Spontaneous breathing preserved yes yes No Patient can protect airway against aspiration yes No No Protection of neurological status yes ? No Easier localization of glottic opening when air is coming out(bubbles) yes Yes/no no Avoidance of cardiovascular depression yes No no Patient cooperation :protude tongue,deep breath,jaw movement… yes no no Time consuming yes yes no Patient discomfort yes no no Disadvantages
  • awake tracheal intubation:when,why,how…l • When? Rosenblatt tree – clinical judgment – preoperative airway assessment • predicted levels of difficulty for both tracheal intubation and mask ventilation – aspiration risk – availability of equipment and assistance – individual’s self-assessment of his or her own skill, knowledge, and familiarity with MO. • Why? • knowledge of the anatomical and physiological characteristics of obesity that provide an understanding of why problems can arise. • How?? • management strategies • airway adjuncts and techniques
  • Rosenblatt WH. The Airway Approach Algorithm: a decision tree for organizing preoperative airway information. J Clin Anesth. 2004;16(4):312–316. • Rosenblatt logical way – Airway Approach Algorithm. – Responses to five clinical questions determine the entry point into the DAA. • 1. 2. 3. 4. 5. Must the airway be managed? Is there potential for difficult laryngoscopy? Can supralaryngeal ventilation be used? Is the stomach empty? Will the patient tolerate an apneic period?
  • A negative answer to any question directs the clinician to a root point of the DAA.(diff.air.algor) A positive answer leads the operator to the next question.
  • Must the airway be managed? • • • • Avoidance of a general anesthetic is desirable for surgical patients with obesity since a regional anesthetic will minimize cardiorespiratory risks and shorten recovery time. regional anesthesia is technically challenging in patients with MO and failure rates are high regional anesthesia may not be appropriate for a particular operation. Sedation techniques in patients with MO require great care since hypoxia will occur at even light levels and airway obstruction and collapse is a risk. For patients with MO requiring general anesthesia the airway should be secured with either a tracheal tube or laryngeal mask airway (LMA).
  • Is there potential for difficult laryngoscopy? • While obesity does not predict difficult tracheal intubation per se, certain features have been associated with an increased risk of difficulty • High Mallampati score (3 or 4) • Increased neck circumference • Excessive pre-tracheal adipose tissue • Severe obstructive sleep apnea (OSA). – – • • • • Male sex, Diabetes Even so, most patients who have some or even all of these features frequently pose no intubation problems. Therefore, recommendations regarding a cut-off Mallampati score or gender-specific neck circumference that can be applied to clinical practice are lacking. In addition, these risk factors are derived from studies considering direct laryngoscopy, so their application to other intubation techniques may not be valid. Intubation problems are said to occur as much as three times more frequently in patients with MO compared to patients who do not have MO,*3,10,11+ but this statement is not supported by several studies.*5,12+ The reason is that “difficult intubation” is not uniformly defined. Clinical studies of laryngoscopy and intubation are biased since patients preoperatively considered to be especially difficult are frequently excluded when clinical judgment suggests awake intubation; therefore, the prediction is never tested. The laryngoscopist cannot be blinded to the patient’s body habitus. Some studies have used an intubation difficulty scale (IDS) that includes potentially subjective elements. It is worth noting that studies using the IDS have found obesity per se to be a risk factor for difficult intubation,[11] whereas those using actual view on laryngoscopy have not.[5,13] Many of these studies are from bariatric surgical populations, groups which typically consist of a larger proportion of female patients. Higher rates of OSA, a risk factor for laryngoscopy difficulties, occur more often in men. It is therefore possible that many studies are of females in whom the anatomical impact of obesity on airway management is reduced. Lack of a standard intubating position for patients with MO is a further cause of confusion. The standard sniffing position does not produce the same alignment of axes for tracheal intubation in patients with MO as it does in patients with BMIs less than 30kg/m[2]. Patients with MO require more elevation of the head, neck, and shoulders so that the sternum and ears are aligned in a horizontal line (head-elevated laryngoscopy position). In this position the view during direct laryngoscopy is significantly improved.[14] Therefore, in some studies suboptimal positioning may have resulted in poorer views, hence more difficulty.
  • Can supralaryngeal ventilation be used? • The consequences of failure to intubate may not be serious if oxygenation can be maintained by facemask or with LMA ventilation. Difficult or impossible facemask ventilation is rare, even in patients with MO. However, increased body mass index (BMI) and OSA are independent predictors for difficult mask ventilation.[15] Adipose tissue in the face and cheeks or the presence of facial hair can interfere with the application of a tight-fitting mask. • When mask ventilation fails, “rescue” alternatives, such as supralaryngeal devices (LMA, the Combitube) must be available.[16,17] These intra-oral devices avoid many of the factors that contribute to difficult mask ventilation and can allow successful, temporary ventilation.[18] They can serve as a bridge to, or a conduit for, tracheal intubation. • They should not be used as the definitive airway since they may be inadequate at the higher pressures needed to ventilate a patient with MO with resulting oropharyngeal leaks or gastric distention.
  • Is the stomach empty? • When tracheal intubation has failed, rescue supraglottic ventilation can only be maintained safely when there is no gastric aspiration risk. • Some consider all patients with MO at risk for gastric aspiration, but for elective surgery the fasted patient with MO is probably at no greater risk than a patient with normal weight. • Exceptions are post-gastric banding surgical patients due to high preoperative residual gastric volumes. • Patients with MO presenting for emergency and trauma surgery, and those with severe gastric reflux disease are also aspiration risks.
  • Jean J, Compere V, Fourdrinier V, et al. The risk of pulmonary aspiration in patients after weight loss due to bariatric surgery. Anesth Analg. 2008;107(4):1257–1259 • Postbariatric(patients who had previous bariatric surgery (gastric banding or gastroplasty)for MO vs control group of obese patients who had not previously undergone bariatric surgery • 4 cases of aspiration in paralyzed patients not associated with difficult intubation.
  • decrease in esophageal-gastric peristalsis and an impairment of lower esophageal sphincter relaxation – Presutti RJ, Gorman RS, Swain JM. Primary care perspective on bariatric surgery. Mayo Clin Proc 2004;79:1158–66 – Kocian R, Spahn DR. Bronchial aspiration in patients after weight loss due to gastric banding. Anesth Analg 2005;100:1856–7 4
  • physiological modifications induced by bariatric surgery . • esophageal-gastric peristalsis is altered after gastric banding. – Gadenstatter M, Aigner F, Wetscher GJ. Treatment of morbid obesity with laparoscopic adjustable gastric banding affectsesophageal motility. Am J Surg 2000;180:479–82. – Dixon JB, O’Brien PE. Gastroesophageal reflux in obesity: the effect of lap-band placement. Rapid and major improvement in symptoms of GERD occurs after LapBand placement. Obes Surg 1999;9:527–31 0,11 • lower esophageal sphincter relaxation impairment is also reported. • M, Aigner F, Wetscher GJ. Adjustable gastric and esophagogastric banding: a randomized clinical trial. Obes Surg 2002;12:573–8 • After vertical banded gastroplasty, a decrease in basal lower esophageal sphincter pressure and an increase in acid reflux were also observed. – Di Francesco V, Baggio E, Mastromauro M, Zoico E, StefenelliN, Zamboni M, Panourgia MP, Frulloni L, Bovo P, Bosello O,Cavallini G. Obesity and gastrooesophageal acid reflux: physiopathological mechanisms and role of gastric bariatric surgery.Obes Surg 2004;14:1095–102
  • Will the patient tolerate an apneic period? • Obesity is associated with a marked reduction in lung volume and significant ventilation/perfusion mismatch. • Low oxygen reserves and high metabolic rate results in rapid hemoglobin desaturation if difficulty is encountered. • Even with maximal pre-oxygenation, severe hypoxia will develop before spontaneous respirations return after anesthetic induction, even when the short-acting muscle relaxant succinylcholine is used. • SEE OUR INTRODUCTION on PREOXYGENATION AND MEANS TO IMPROVE IT
  • • Considering the questions posed by the Airway Approach Algorithm provides a means for deciding on whether to proceed with anesthetic induction and direct laryngoscopy, or an awake intubation.
  • Procedi con l’induzione/intubazione • patient is properly positioned;ramp • adequately pre-oxygenated;pREo2 + peep+RM • a backup plan is considered;PREPARE Rescue • most patients with MO can be safely intubated following anesthetic induction
  • Awake intubation • significant risk of aspiration • any doubt regarding ability to intubate or to mask ventilate, • awake intubation is better particularly true for the small subset of patients with MO who have features associated with both difficult mask ventilation and difficult intubation: – – – – – Massive central obesity;superobese severe OSA high Mallampati score short, wide neck. Other anatomical problems
  • How? Intubation Strategies for Awake Intubation • • • • • • Caution should be always taken when administering sedative drugs since airway obstruction may occur even with minimal sedation, especially in patients with OSA. Application of local anesthesia to the vocal cords and infraglottic structures does not increase the risk of aspiration from a full stomach, provided that the patient is not oversedated. Adequate airway anesthesia is vitally important for success. Superior laryngeal nerve blocks and trans-tracheal injection of local anesthetic via the cricothyroid membrane can improve patient comfort. Nerve blocks of the airway can be technically challenging. Noninvasive techniques, such as nebulization, may result in administration of large doses of local anesthetic with unpredictable effects as solution is lost to the atmosphere. Atomization of 2 or 4% lidocaine does provide satisfactory conditions. Careful titration of the ultra-short acting opioid remifentanil or the selective alpha-2 adrenergic agonist dexmedetomine can provide satisfactory conditions for awake intubation in patients with MO
  • Flexible fiberoptic laryngoscopy:FOB • • • • • • • visualization of the vocal cords may prove difficult when excess fat deposits cause airway narrowing and redundant folds of tissue. Instructing the patient to both protrude the tongue and phonate can increase the diameter of the airway and aid visualization. Sitting utilizes the effect of gravity and may also increase the pharyngeal space. Using the nasal rather than the oral route provides a straighter passage of the fiberscope, but increases the risk of epistaxis if adequate vasoconstriction of the nasal mucosa is not achieved. :lidocaine + adrenaline 1:200.000-1:500.000 (50 cc of lidoc 1%+0.25 or 0.1 mg of adrenaline) Supplemental O2 can be delivered through the working channel of the flexible scope. One must avoid passing the distal tip of the flexible scope beyond the carina because barotrauma can result following oxygen insufflation. The pharyngeal airway may be splinted open during nasal fiberoptic intubation by application of nasal continuous positive airway pressure (CPAP) on the contra lateral nostril.
  • LMA as a FOB coduit • If technical difficulties arise with flexible fiberoptic laryngoscopy, a LMA can be used as a conduit for the fiberscope. • The LMA stents surrounding soft tissues open and permit a technically easier passage of the fiberscope. • Positioning and inflation of the LMA can be uncomfortable, but asking the patient to swallow the device aids insertion. • Once in situ, it is usually tolerated, although swallowing and salivation are common. As well as functioning as a conduit for fiberoptic scope, the LMA provides a means of delivering oxygen. With the LMA Proseal™ one can even deliver positive pressure ventilation during the intubation procedure in patients with MO.
  • • Blind passage of a tracheal tube via the intubating (LMA Fastrach™, The Laryngeal Mask Company Limited) LMA is highly successful in MO patients and can be achieved in shorter time when compared with flexible fiberoptic intubation via the Ovassapian Airway (Hudson RCI, Durham, North Carolina). • The newer LMA CTrach™ (LMA PacMed Pty Ltd., Burnley Vic, Australia) permits visualization of the glottic opening on a monitor while allowing oxygenation during the intubation process • In addition to these LMA devices, videolaryngoscopy is being utililized with increasing frequency. Alignment of the axes necessary for intubation by direct laryngoscopy is not necessary and since less force is used to obtain glottic exposure, these devices may prove more suitable for awake intubation. The Pentax Airway Scope™ (Pentax Corporation, Tokyo, Japan) and the Airtraq (Prodol Meditec S.A., Vizcaya, Spain) have been used in patients wth MO.
  • SURGICAL AIRWAY
  • Surgical airway • Sono convinto che la tracheostomia sia più difficile negli obesi…non fosse altro che per la difficoltà dei punti di repere in un collo grosso e corto! • Una soluzione(difficilmente praticabile in emergenza) potrebbe essere offerta dall’eco del collo:
  • THE END
  • Obesity and Difficult Intubation: Where Is the Evidence? • ? • To the Editor:—We read Shiga et al.’s meta-analysis of predictors of • difficult tracheal intubation.1 They analyzed four studies involving • obese patients2–5 and concluded that intubation problems are three • times more likely to occur in this patient population compared with • normal-weight patients. • Although the standard sniffing position for tracheal intubation is • achieved in nonobese patients by raising the occiput 8 to 10 cm with • a pillow or head rest, obese patients require much greater elevation of
  • J Clin Anesth. 2009 Aug;21(5):348-51. Epub 2009 Aug 22. A retrospective analysis of airway management in obese patients at a teaching institution. Hagberg CA, Vogt-Harenkamp C, Kamal J. • Department of Anesthesiology, The University of Texas Medical School at Houston, Houston, TX 77030, USA. carin.a.hagberg@uth.tmc.edu • • • • • • • • • • • • STUDY OBJECTIVE: To identify patient characteristics that influence the choice of awake fiberoptic intubation (AFI) versus intubation after general anesthesia in obese patients. DESIGN: Retrospective study. SETTING: Memorial Hermann Hospital, Houston, TX. MEASUREMENTS: Perioperative records of 283 obese patients [body mass index (BMI) >34 kg/m2] who underwent elective surgery between January 1991 and December 1999 were studied. Patients' data were divided into two groups according to method of induction and intubation: asleep direct laryngoscopy versus AFI. Patient demographics, BMI, Mallampati airway classification, history of gastroesophageal reflux disease, peptic ulcer disease, hiatal hernia, and obstructive sleep apnea syndrome were compared between the two groups. Bivariate and multivariate analyses were performed. MAIN RESULTS: AFI was performed in 12 (4.2%) obese patients, and direct laryngoscopy was performed in 271 (95.8%) obese patients. Difficult intubation was reported in 21 (7.4%) cases, and there were no reported cases of failed intubations. Bivariate analyses demonstrated that AFI patients were more likely to have a BMI > or = 60 kg/m2 (P < 0.001), Mallampati class III or IV airway (P < 0.001), and be men (P = 0.004). These three factors were also statistically significant in the multivariate logistic regression. In particular, each one kg/m(2) increase in BMI was associated with a 7% increased likelihood of AFI. Men were approximately 4 times likelier than women to have an AFI. Compared with patients with a Mallampati Class I or II airway, those with Mallampati Classes III or IV were about 26 times as likelier to have an AFI. CONCLUSIONS: Patients selected for AFI were predominantly men, with a Mallampati Class III or IV airway, and BMI > or = 60 kg/m2
  • Table 2 Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients Voyagis, G. S.; Kyriakis, K. P.; Dimitriou, V.; Vrettou, I. European Journal of Anaesthesiology. 15(3):330-334, May 1998. doi: Table 2. Distribution of modified oropharyngeal classification according to the presence of obesity Copyright © 2011 European Journal of Anaesthesiology. Published by Lippincott Williams & Wilkins. 165
  • Table 3 Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients Voyagis, G. S.; Kyriakis, K. P.; Dimitriou, V.; Vrettou, I. European Journal of Anaesthesiology. 15(3):330-334, May 1998. doi: Table 3. Distribution of results of direct laryngoscopy using the pre-operative assessment of the modified oropharyngeal classification and the presence of obesity Copyright © 2011 European Journal of Anaesthesiology. Published by Lippincott Williams & Wilkins. 166
  • Ndoko SK, Amathieu R, Tual L, Polliand C, Kamoun W, El Housseini L, et al. Tracheal intubation of morbidly obese patients: a randomized trial comparing performance of Macintosh and Airtraq TM laryngoscopes. Br J Anaesth 2008;100:263-8. • • • • • • • • • • • • • • • • • • • • Background. The AirtraqTM laryngoscope is designed to allow visualization of the glottis without alignment of the oral, pharyngeal, and laryngeal axes. We hypothesized that this new airway device would facilitate tracheal intubation of morbidly obese patients. We compared tracheal intubation performance of standard Macintosh laryngoscope with the AirtraqTM laryngoscope in morbidly obese patients. Methods. One hundred and six consecutive ASA I–III morbidly obese patients undergoing surgery were randomized to intubation with the Macintosh laryngoscope or the AirtraqTM laryngoscope. Induction of anaesthesia was standardized. If tracheal intubation failed within 120 s with the Macintosh or AirtraqTM, laryngoscopes were switched. Success rate, SpO2, duration of tracheal intubation, and quality of airway management were evaluated and compared between the groups. Results. Preoperative characteristics of the patients were similar in both groups. In the AirtraqTM group, tracheal intubation was successfully carried out in all patients within 120 s. In the Macintosh laryngoscope group, six patients required intubation with the AirtraqTM laryngoscope. The mean (SD) time taken for tracheal intubation was 24 (16) and 56 (23) s, respectively, with the AirtraqTM and Macintosh laryngoscopes, (P,0.001). SpO2 was better maintained in the AirtraqTM group than in the Macintosh laryngoscope group with one and nine patients, respectively, demonstrating drops of SpO2 to 92% or less (P,0.05). Conclusions. In this study, the AirtraqTM laryngoscope shortened the duration of tracheal intubation and prevented reductions in arterial oxygen saturation in morbidly obese patients.
  • ANATOMIA( E FISIOLOGIA) DELLE VIE AEREE DEGLI OBESI
  • • Decreased pharyngeal area and volume in obesity associated with the deposition of adipose tissue, predominantly in the lateral pharyngeal walls. – Horner RL, Mohiaddin RH, Lowell DG, Shea SA, Burman ED, Longmore DB, Guz A: Sites and sizes of fat deposits around the pharynx in obese patients with obstructive sleep apnoea and weight matched controls. Eur Respir J 1989;2:613–22 – Schwab RJ, Gupta KB, Gefter WB, Metzger LJ, Hoffman EA, Pack AI: Upper airway and soft tissue anatomy in normal subjects and patients with sleep disordered breathing: Significance of the lateral pharyngeal walls. Am J Respir Crit Care Med 1995; 152:1673–89
  • • • • • • • • Eur Respir J. 1989 Jul;2(7):613-22. Sites and sizes of fat deposits around the pharynx in obese patients with obstructive sleep apnoea and weight matched controls. Horner RL, Mohiaddin RH, Lowell DG, Shea SA, Burman ED, Longmore DB, Guz A. Source Department of Medicine, Charing Cross and Westminster Medical School, London, U.K. Abstract It has been suggested that deposition of fat in the soft tissues surrounding the upper airway may be an important factor in the pathogenesis of obstructive sleep apnoea (OSA) in obese subjects. We have used magnetic resonance imaging to determine the site(s) and size(s) of fat deposits around the upper airway in six obese patients with OSA (116-153% of ideal body weight) and five weightmatched controls without OSA (107-152% of ideal body weight). In all subjects, large deposits of fat were present postero-lateral to the oropharyngeal airspace at the level of the soft palate. Significantly more fat was present in these regions in the patients with OSA (p = 0.03). Fat deposits in the soft palate were observed in 4 of the 6 patients with OSA but none of the controls. Fatty streaks were observed in the tongue in 2 of the 5 controls and 3 of the 6 patients with OSA. Fat deposits were observed anterior to the laryngopharyngeal airspace, in submental regions, in all obese subjects. This study shows that more fat is present in those areas surrounding the collapsable segment of the pharynx in patients with OSA, compared to equally obese control subjects without OSA
  • • • • • • • • Eur Respir J. 1999 Feb;13(2):403-10. Cephalometric abnormalities in non-obese and obese patients with obstructive sleep apnoea. Sakakibara H, Tong M, Matsushita K, Hirata M, Konishi Y, Suetsugu S. Source Dept of Internal Medicine, Fujita Health University, School of Medicine, Toyoake, Aichi, Japan. Abstract The aim of this work was to comprehensively evaluate the cephalometric features in Japanese patients with obstructive sleep apnoea (OSA) and to elucidate the relationship between cephalometric variables and severity of apnoea. Forty-eight cephalometric variables were measured in 37 healthy males and 114 male OSA patients, who were classed into 54 non-obese (body mass index (BMI) <27 kg x m(-2), apnoea-hypopnoea index (AHI)=25.3+/-16.1 events x h(-1)) and 60 obese (BMI > or = 27 kg x m(-2), AHI=45.6+/-28.0 events h(-1)) groups. Diagnostic polysomnography was carried out in all of the OSA patients and in 19 of the normal controls. The non-obese OSA patients showed several cephalometric defects compared with their BMI-matched normal controls: 1) decreased facial A-P distance at cranial base, maxilla and mandible levels and decreased bony pharynx width; 2) enlarged tongue and inferior shift of the tongue volume; 3) enlarged soft palate; 4) inferiorly positioned hyoid bone; and 5) decreased upper airway width at four different levels. More extensive and severe soft tissue abnormalities with a few defects in craniofacial bony structures were found in the obese OSA group. For the non-obese OSA group, the stepwise regression model on AHI was significant with two bony structure variables as determinants: anterior cranial base length (S-N) and mandibular length (Me-Go). Although the regression model retained only linear distance between anterior vertebra and hyoid bone (H-VL) as an explainable determinant for AHI in the obese OSA group, H-VL was significantly correlated with soft tissue measurements such as overall tongue area (Ton), inferior tongue area (Ton2) and pharyngeal airway length (PNS-V). In conclusion, Japanese obstructive sleep apnoea patients have a series of cephalometric abnormalities similar to those described in Caucasian patients, and that the aetiology of obstructive sleep apnoea in obese patients may be different from that in non-obese patients. In obese patients, upper airway soft tissue enlargement may play a more important role in the development of obstructive sleep apnoea, whereas in nonobese patients, bony structure discrepancies may be the dominant contributing factors for obstructive sleep apnoea
  • • • • • • • • Eur Respir J. 1999 Feb;13(2):398-402. Effect of obesity and erect/supine posture on lateral cephalometry: relationship to sleep-disordered breathing. Brander PE, Mortimore IL, Douglas NJ. Source Dept of Pulmonary Medicine, Hyvinkää District Hospital, Finland. Abstract Craniofacial and upper airway anatomy, obesity and posture may all play a role in compromising upper airway patency in patients with the sleep apnoea/hypopnoea syndrome. The aim of this study was to investigate the relationship between obesity, facial structure and severity of sleep-disordered breathing using lateral cephalometric measurements and to assess the effect of body posture on cephalometric measurements of upper airway calibre variables in obese and non-obese subjects. Lateral cephalometry was carried out in erect and supine postures in 73 awake male subjects randomly selected from patients referred for polysomnography who had a wide range of apnoea/hypopnoea frequencies (1-131 events x h sleep(-1)). Subjects were divided into nonobese (body mass index (BMI) < 30 kg x m(-2); n=42) and obese (BMI > or = 30 kg x m(-2); n=31) groups. Significant but weak correlations were found between apnoea/hypopnoea index (AHI) and measurements reflecting upper airway dimensions: uvular protrusion-posterior pharyngeal wall (r=-0.26, p<0.05) and hyoidposterior pharyngeal wall (r=0.26, p<0.05). Multiple regression using both upper airway dimensions improved the correlation to AHI (r=0.34, p=0.01). Obese subjects had greater hyoid-posterior pharyngeal wall distances than non-obese subjects, both erect (42+/-5 versus 39+/-4 mm, respectively (mean+/-SD) p<0.01) and supine (43+/-5 versus 40+/-4 mm, p<0.05). Skeletal craniofacial structure was similar in obese and non-obese subjects. In conclusion, measurements reflecting upper airway size were correlated with the severity of sleep-disordered breathing. Differences in upper airway size measurements between obese and non-obese subjects were independent of bony craniofacial structure.
  • • • • • • • • Eur Respir J. 1996 Sep;9(9):1801-9. Relationship between body mass index, age and upper airway measurements in snorers and sleep apnoea patients. Mayer P, Pépin JL, Bettega G, Veale D, Ferretti G, Deschaux C, Lévy P. Source Dept of Respiratory Medicine, ANTADIR, Quebec, Canada. Abstract Anatomical pharyngeal and craniofacial abnormalities have been reported using upper airway imaging in snorers with or without obstructive sleep apnoea (OSA). However, the influences of the age and weight of the patient on these abnormalities remain to be established. The aim of this study was, therefore, to evaluate in a large population of snorers with or without OSA, the relationship between body mass index (BMI), age and upper airway morphology. One hundred and forty patients were referred for assessment of a possible sleep-related breathing disorder and had complete polysomnography, cephalometry and upper airway computed tomography. For the whole population, OSA patients had more upper airway abnormalities than snorers. When subdivided for BMI and age, however, only lean or younger OSA patients were significantly different from snorers as regards their upper airway anatomy. The shape of the oropharynx and hypopharynx changed significantly with BMI both in OSA patients and snorers, being more spherical in the highest BMI group due mainly to a decrease in the transverse axis. On the other hand, older patients (> 63 yrs), whether snorers or apnoeics, had larger upper airways at all pharyngeal levels than the youngest group of patients (< 52 yrs). For the total group of patients, upper airway variables explained 26% of the variance in apnoea/hypopnoea index (AHI), whereas in lean (BMI < 27 kg.m-2) or youngest (age < 52 yrs) subjects upper airway variables explained, respectively 69 and 55% of the variance in AHI. In conclusion, in lean or young subjects, upper airway abnormalities explain a major part of the variance in apnoea/hypopnoea index and are likely to play an important physiopathogenic role. This study also suggests that the shape of the pharyngeal lumen in awake subjects is more dependent on body mass index than on the presence of obstructive sleep apnoea. Further investigation looking at upper airway imaging for surgical selection in obstructive sleep apnoea should focus on lean and young patients
  • • AJNR Am J Neuroradiol. 2005 Nov-Dec;26(10):2624-9. • Evaluation of the upper airway cross-sectional area changes in different degrees of severity of obstructive sleep apnea syndrome: cephalometric and dynamic CT study. • Yucel A, Unlu M, Haktanir A, Acar M, Fidan F. • • • • • • • • • • • Source Department of Radiology, Afyon Kocatepe University School of Medicine, Afyon, Turkey. Abstract BACKGROUND AND PURPOSE: The upper airway lumen is narrower in patients with obstructive sleep apnea syndrome (OSAS) than normal subjects. In this study, we examined changes of the upper airway cross-sectional area in each phase of respiration in different degrees of severity of OSAS with dynamic CT and investigated whether these changes have any correlation with sleep apnea severity parameters, including polysomnography (PSG) and cephalometry. MATERIALS AND METHODS: Between May and November 2004, 47 patients who had at least 2 of 3 major symptoms of snoring, daytime somnolence, and apnea with witness were included in this prospective study. As control group, 24 habitual snorers were studied. All patients underwent PSG and upper airway CT. The average number of episodes of apnea and hypopnea per hour of sleep (the apnea-hypopnea index, AHI) was calculated. An AHI of 5 -29 represented mild/moderate OSAS and an AHI > or = 30 represented severe OSAS. Cross-sectional area of the airway at the level of oropharynx and hypopharynx were obtained in each phase of quiet tidal breathing and at the end of both the forced inspiration and expiration. Six standard cephalometric measurements were made on the lateral scout view. All parameters were compared between controls and mild/moderate and severe OSAS groups. RESULTS: Twenty-seven patients had mild/moderate OSAS, and 20 patients had severe OSAS. Patients with severe OSAS had significantly narrower crosssectional area at the level of uvula in expiration, more inferiorly positioned hyoid bone, and thicker soft palate compared with patients with mild/moderate OSAS (P < .05) and the control group (P < .05). In addition, severe OSAS patients had bigger neck circumference than those in the control group (P < .05). CONCLUSION: Patients with severe OSAS had significant differences in the parameters. Measurement of the cross-sectional area of oropharynx in expiration can especially be useful for diagnosis of severe OSAS as a new key point
  • • • • • • • • • • • • • • • • • Chest. 2003 Jul;124(1):212-8. Cephalometric analysis in obese and nonobese patients with obstructive sleep apnea syndrome. Yu X, Fujimoto K, Urushibata K, Matsuzawa Y, Kubo K. Source First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan. Abstract STUDY OBJECTIVES: The aims of this study were to comprehensively evaluate the cephalometric features of patients with obstructive sleep apnea syndrome (OSAS), and to elucidate the relationship between cephalometric variables and severity of the apnea-hypopnea index (AHI). PATIENTS: The study population consisted of 62 male patients with OSAS, classified into 33 obese patients (body mass index [BMI] >or= 27) and 29 nonobese patients (BMI < 27), and 13 male simple snorers (AHI < 5 events per hour). METHOD: and measurements: Diagnostic polysomnography and measurements of 22 cephalometric variables were carried out for all patients and simple snorers. RESULTS: Patients with OSAS in both subgroups showed several significant cephalometric features compared with simple snorers: (1) inferiorly positioned hyoid bone, (2) enlarged soft palate, and (3) reduced upper airway width at soft palate. More extensive and severe soft-tissue enlargements including anteriorly positioned hyoid bone and a longer tongue were found in the obese patients. In the nonobese patients, the anteroposterior distances of the bony nasopharynx and oropharynx were significantly smaller than those of simple snorers and obese patients. Stepwise regression analysis showed that anterior displacement of the hyoid bone and retroposition of the mandible were the dominant overall determinants for AHI in patients with OSAS, and that narrowing of the bony oropharynx and inferior displacement of the hyoid bone were dominant determinants for AHI in nonobese patients. A significant regression model for AHI using cephalometric variables could not be obtained for the obese patients, but the BMI proved to be the most significant determinant. CONCLUSION: Characteristics of the craniofacial bony structure such as narrowing of the nasopharynx and oropharynx and enlargement of the soft tissue in the upper airway may be important risk factors for the development of OSAS in nonobese patients. In obese patients, the deposition of adipose tissue in the upper airway may aggravate the severity of OSAS
  • • • • • • • • • • • • • • • • Rev Stomatol Chir Maxillofac. 2001 Nov;102(6):305-11. [Comparison of the cephalometric characteristics of snoring patients and apneic patients as a function of the degree of obesity. Apropos of 162 cases]. [Article in French] Iked N, Hazime N, Dekeister C, Folia M, Tiberge M, Paoli JR. Source Service de Stomatologie et Chirurgie Maxillo-Faciale, Hôpital Rangueil, CHU Toulouse, 1 avenue Jean Poulhes, 31 403 Toulouse. Abstract BACKGROUND: The purpose of our study was to compare cephalometric analysis of craniofacial features in normal weight or obese subjects who are habitual snorers or apneic. We conducted a retrospective comparison of their clinical and cephalometric features by degree of obesity. PATIENTS AND METHODS: One hundred and sixty two male subjects with obstructive sleep apnea syndrome (OSAS) diagnosed by conventional polysomnography were included in the study. Patients were divided into four groups according to their body mass index (BMI) and their apnea/hypopnea index (AHI: Group 1 = normal-weight snorers (34 patients), Group 2 = normal-weight apneic subjects (40 patients), Group 3 = obese snorers (20 patients), Group 4 = obese apneic subjects (68 patients). Lateral cephalometry was performed in all patients. Intergroup comparisons (2/4, 1/2, 3/4) were made using 32 parameters to study the influence of the size of bone structures, their relationships, and size of the upper airways. RESULTS: The four groups were comparable for age. AHI was higher for group 4 (obese apneic) compared with group 1 (normal-weight snorers). Compared with group 3 (obese snorers), group 1 (normal-weight snorers) had a retroposition of the mandible (smaller SNB and ANB angle), an accentuated facial divergence and a narrower pharyngeal space at the hyoid bone level. Compared with group 1 (normal-weight snorers), group 2 (normal-weight apneic) had a narrower pharyngeal space at different levels. Compared with group 3 (obese snorers), group 4 (obese apneic) had a lower hyoid bone evaluated with different cephalometric variables. CONCLUSION: This study mainly shows that apneic patients exhibit craniofacial differences when divided into two groups according to their body mass index. Our findings are consistent with previous reports and could suggest a dual etiology of OSAS
  • • • • • • • • • • • • • • • • • • • J Craniomaxillofac Surg. 2000 Aug;28(4):204-12. Obstructive sleep apnoea: multiple comparisons of cephalometric variables of obese and non-obese patients. Tangugsorn V, Krogstad O, Espeland L, Lyberg T. Source Department of Orthodontics, Institute of Clinical Dentistry, University of Oslo, Norway. Abstract BACKGROUND: Pathogenesis of obstructive sleep apnoea (OSA) is complex and not yet fully understood. Several factors contribute to OSA severity. Obesity is believed to play an important role. Nevertheless, not all OSA patients are obese. Therefore, the different features that cause nocturnal upper airway obstruction in obese and non-obese OSA patients could be expected. PURPOSE: To investigate the different components of cervico-craniofacial skeletal and upper airway soft tissue morphology among obese OSA, non-obese OSA patients and the controls. PATIENTS: One hundred male OSA patients were classified into two groups on the basis of body mass index (BMI) as obese (BMI > or = 30 kg/m2) and non-obese (BMI < 30 kg/m2). Consequently, 57 obese and 43 non-obese OSA patients were examined and compared with a control group of 36 healthy males. STUDY DESIGN: A comprehensive cephalometric analysis of cervico-craniofacial skeletal and upper airway soft tissue morphology was performed. Sixty-eight cephalometric variables were compared among the three groups by one way analysis of variance with Bonferroni's test. RESULTS: Both OSA groups had aberrations of cervico-craniofacial skeletal as well as upper airway soft tissue morphology when compared with the controls. These anatomic deviations were confined to cervico-craniofacial skeletal structures in the non-obese OSA patients, whereas the obese OSA patients had more abnormalities in the upper airway soft tissue morphology, head posture and position of the hyoid bone. CONCLUSION: The findings imply that there should be different treatment regimens for the two subgroups of OSA patients. Cephalometric analysis together with various considerations of BMI is highly recommended as one of the most important tools in diagnosis and treatment planning for OSA patients
  • • • • • • • • Eur J Orthod. 1999 Aug;21(4):363-76. Changes in airway and hyoid position in response to mandibular protrusion in subjects with obstructive sleep apnoea (OSA). Battagel JM, Johal A, L'Estrange PR, Croft CB, Kotecha B. Source Department of Orthodontics, St Bartholomew's and the Royal London School of Medicine and Dentistry, UK. Abstract This prospective clinical study examined the alterations in airway and hyoid position in response to mandibular advancement in subjects with mild and moderate obstructive sleep apnoea (OSA). Pairs of supine lateral skull radiographs were obtained for 13 female and 45 male, dentate Caucasians. In the first film, the teeth were in maximal intercuspation, while in the second the mandible was postured forwards into a position of maximum comfortable protrusion. Radiographs were traced and digitized, and the alterations in the pharyngeal airway and position of the hyoid were examined. Males and females were analysed separately. In males only, correlations were sought between the changes in hyoid and airway parameters, and the initial and differential radiographic measurements. In males, mean mandibular protrusion at the tip of the lower incisor was 5.3 mm, increasing its distance from the posterior pharyngeal wall by 6.9 mm (or 9 per cent). Movement of the hyoid showed extreme inter-subject variability, both in the amount and direction. In relation to the protruded lower jaw, the hyoid became closer to the gonion by 6.9 mm and to the mandibular plane by 4.3 mm. With respect to the upper face, a 1.3-mm upward and 1.1-mm forward repositioning was seen. The percentage alterations in airway dimensions matched or bettered the mandibular advancement. The minimum distances behind the soft palate and tongue improved by 1.0 and 0.8 mm, respectively. Despite their smaller faces, females frequently showed greater responses to mandibular protrusion than males. No cephalometric features could be identified which might indicate a favourable response of the airway to mandibular protrusion. Larger increments of hyoid movement were associated with an improved airway response, but the strength of the correlations was generally low.
  • • • • Diabetes Care. 2008 Feb;31 Suppl 2:S303-9. Abdominal fat and sleep apnea: the chicken or the egg? Pillar G, Shehadeh N. • • • Source Sleep Lab, Meyer Children's Hospital, Rambam Medical Center, Haifa, Israel. gpillar@tx.technion.ac.il Abstract • Obstructive sleep apnea (OSA) syndrome is a disorder characterized by repetitive episodes of upper airway obstruction that occur during sleep. Associated features include loud snoring, fragmented sleep, repetitive hypoxemia/hypercapnia, daytime sleepiness, and cardiovascular complications. The prevalence of OSA is 2-3% and 4-5% in middle-aged women and men, respectively. The prevalence of OSA among obese patients exceeds 30%, reaching as high as 50-98% in the morbidly obese population. Obesity is probably the most important risk factor for the development of OSA. Some 60-90% of adults with OSA are overweight, and the relative risk of OSA in obesity (BMI >29 kg/m(2)) is >or=10. Numerous studies have shown the development or worsening of OSA with increasing weight, as opposed to substantial improvement with weight reduction. There are several mechanisms responsible for the increased risk of OSA with obesity. These include reduced pharyngeal lumen size due to fatty tissue within the airway or in its lateral walls, decreased upper airway muscle protective force due to fatty deposits in the muscle, and reduced upper airway size secondary to mass effect of the large abdomen on the chest wall and tracheal traction. These mechanisms emphasize the great importance of fat accumulated in the abdomen and neck regions compared with the peripheral one. It is the abdomen much more than the thighs that affect the upper airway size and function. Hence, obesity is associated with increased upper airway collapsibility (even in nonapneic subjects), with dramatic improvement after weight reduction. Conversely, OSA may itself predispose individuals to worsening obesity because of sleep deprivation, daytime somnolence, and disrupted metabolism. OSA is associated with increased sympathetic activation, sleep fragmentation, ineffective sleep, and insulin resistance, potentially leading to diabetes and aggravation of obesity. Furthermore, OSA may be associated with changes in leptin, ghrelin, and orexin levels; increased appetite and caloric intake; and again exacerbating obesity. Thus, it appears that obesity and OSA form a vicious cycle where each results in worsening of the other.
  • • • • • • • • Pediatrics. 2011 Apr 4. [Epub ahead of print] Association of Neck Circumference With Perioperative Adverse Respiratory Events in Children. Nafiu OO, Burke CC, Gupta R, Christensen R, Reynolds PI, Malviya S. Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan. Abstract Objective: The purpose of this investigation was to examine the association of neck circumference (NC) with perioperative respiratory adverse events in children undergoing elective noncardiac surgery, a relationship that has not been previously characterized. Methods: Using a prospective, observational design, we studied children aged 6 to 18 years undergoing elective noncardiac surgeries at our institution. Trained research assistants collected clinical (including perioperative adverse events) and anthropometric data from all subjects. Patients were stratified into 2 classes: high NC versus low NC on the basis of age- and gender-specific receiver operating characteristic curve analysis. Subsequently, univariate factors associated with high NC were explored, and odds ratios for the occurrence of perioperative adverse events were then calculated from logistic regression after controlling for clinically relevant cofactors. Results: Among the 1102 patients, the prevalence of high NC was 24.3%. NC was positively correlated with age and other anthropometric parameters. Children with high NC were more likely to be loud snorers and have a history of bronchial asthma, hypertension, and type 2 diabetes. Composite adverse airway events were more frequent in children with a large NC. There was no significant association between high NC and difficult laryngoscopy in our study population. Conclusions: NC was positively correlated with other indices of obesity in children, and large NC (indicative of central obesity) was associated with some adverse respiratory events in these children undergoing noncardiac surgery. NC could be a useful clinical screening tool for the occurrence of perioperative adverse respiratory events in children Paediatr Anaesth. 2011 Mar 24. doi: 10.1111/j.1460-9592.2011.03559.x. [Epub ahead of print]
  • • • • • • • • Anesth Analg. 2003 May;96(5):1510-5, table of contents. Airway management using the intubating laryngeal mask airway for the morbidly obese patient. Frappier J, Guenoun T, Journois D, Philippe H, Aka E, Cadi P, Silleran-Chassany J, Safran D. Source Department of Anesthesiology and Intensive Care, European Hospital Georges Pompidou, Paris, France. jfrappier@invivo.edu Abstract We studied the effectiveness of the intubating laryngeal mask airway (ILMA) in morbidly obese patients scheduled for bariatric surgery. We included 118 consecutive morbidly obese patients (body mass index, 45 +/- 5 kg/m(2)). After the induction of general anesthesia, the laryngeal view was classified by the first observer according to the method of Cormack and Lehane. The ILMA was then inserted, and the trachea was intubated through the ILMA by a second observer. The The success rate, the number of attemprate of successful tracheal intubation with ILMA was 96.3%. ts, and the total duration of the procedure were not different among patients with low-grade (Cormack 1-2) and patients with high-grade (Cormack 3-4) laryngeal views. The time required for insertion of the ILMA was slightly longer in patients with high-grade laryngeal views. Failures of the technique were not explained by the experience of the practitioner or airway characteristics. No adverse effect related to the technique was reported. Results of this study suggest that using the ILMA provides an additional technique for airway management of morbidly obese patients. IMPLICATIONS: The intubating laryngeal mask airway (ILMA) provides an additional technique for airway management of morbidly obese patients. The best choice of the primary technique (laryngoscopy or ILMA) for tracheal intubation of an adult obese patient remains to be determined
  • • • • • • • • The Association Between Obesity and Difficult Prehospital Tracheal Intubation. Holmberg TJ, Bowman SM, Warner KJ, Vavilala MS, Bulger EM, Copass MK, Sharar SR. From the *Department of Anesthesiology, University of Washington, Seattle, Washington; Abstract Background: Nonphysician advanced life support (ALS) providers often perform tracheal intubation (TI) for cardiac arrest or other life-threatening indications in the prehospital setting, where airway assessment and airway management tools are limited. However, the frequency of difficult TI in obese patients in this setting is unclear. In this study we determined factors associated with TI success, and determined TI difficulty as a function of body mass index (BMI) in a system of ALS providers experienced in TI, to guide future prehospital education efforts. Methods: A retrospective review was performed of all patients ≥15 years of age who underwent prehospital TI by paramedics in the Seattle Medic One system over a 4-year period, and were transported to the regional level 1 trauma center (Harborview Medical Center). Data were abstracted from a prospectively collected prehospital airway management database and from the hospital medical records, including demographic information, number of TI attempts, TI success or failure, and body weight/height (BMI). Descriptive statistics and multivariable logistic regression were calculated, with the primary end point being difficult TI (defined as ≥4 TI attempts or the need to use an alternative airway management technique). Results: Of 80,501 patient contacts in whom 4114 TIs were attempted during the 4-year study period, 823 met study entry criteria (including a calculable BMI). The overall TI success rate in the study population was 98.5% (811 out of 823), with 6.8% (56 out of 823) meeting the predetermined definition for difficult TI. There was no significant association between difficult TI and patient age, gender, use of succinylcholine, or medical diagnosis (trauma vs. nontrauma). In comparison with the lean patient subgroup (BMI <30 kg/m(2)), patients with class III obesity (BMI >40 kg/m(2)) had a significant association with difficult TI (odds ratio 3.68; confidence interval [CI] 1.27-10.59), whereas those with class I/II obesity (BMI ≥30 kg/m(2) and <40 kg/m(2)) did not (odds ratio 0.98; CI 0.46 -2.07). Conclusions: Among prehospital ALS providers with previously documented and published successful TI performance, increased difficulty with TI was observed in patients with extreme obesity, but not in patients with lesser degrees of obesity. Because extreme obesity is an easily identifiable patient characteristic, didactic and clinical (e.g., operating room) airway management education for such providers should emphasize airway management challenges and strategies associated with obesity, including specific equipment, patient positioning, and practice recommendations that may facilitate both TI and alternative airway management techniques in this population J Asthma. 2011 Apr;48(3):217-23. Epub 2011 Feb 21.
  • The extended Mallampati score and a diagnosis of diabetes mellitus are predictors of difficult laryngoscopy in the morbidly obese. Anesth Analg. 2008 Dec;107(6):1919-23 Mashour GA, Kheterpal S, Vanaharam V, Shanks A, Wang LY, Sandberg WS, Tremper KK • • • • • • • • • • • • • • • • • • • • In a realistic clinical setting, we demonstrate that the EMS is superior to the MMP in the prediction of difficult laryngoscopy in the morbidly obese population. The EMS predictions demonstrate better agreement with Cormack-Lehane grades compared to the MMP (P 0.0001) in 23 morbidly obese patients, representing 6.6% of the study population with a more accurate examination (Table 4). Given the widespread and standard use of the Mallampati examination, as well as the increasing number of morbidly obese patients, even small improvements conferred by the EMS could have a clinically significant effect. Since performing the Mallampati examination with craniocervical extension is usually low risk, time efficient, and inexpensive, it is worthwhile considering this position for routine use. Our data show that EMS class 3 or 4 in the morbidly obese, compared to MMP and other standard methods of airway evaluation is a better predictor of difficult laryngoscopy (Table 5). Other commonly used bedside
  • Hekiert, A., Mick, R., & Mirza, N. (2007). Prediction of difficult laryngoscopy: does obesity play a role? Annals of otology, rhinology & laryngology, 116(11), 799-804. • • • • • • • • • • • • • • • • • • Hekiert, Mick & Mirza (2007) prospectively evaluated 63 obese patients with a BMI >30 pre-operatively and during direct layrngoscopy. They wanted to identify preoperative predictors of difficult laryngoscopy and any relationships that could be linked to obesity. A visual analog score (VAS) 1-10 was used to grade the laryngeal exposure, a score of at least 3 was considered difficult. VAS score correlated with the Mallampati scores highly positive (p<0.001) and also the Cormack-Lehane score (p<0.001). The correlations were not gender specific. Correlation between the VAS score and BMI was demonstrated (p<0.007) but only weakly for weight (p=0.05) and neck circumference (p=0.07). Correlation of patient characteristics and the Mallampati score was determined to have a high positive correlation in three categories; neck circumference (p<0.001), weight (p<0.001) and BMI (p<0.001). Again this was not gender specific. The Mallampati scores did correlate with the Cormack-Lehane scores (p<0.009), with a significantly stronger correlation with women. When evaluating patient 41 characteristics and the Cormack-Lehane score for correlation statistical significance was lacking. A weak positive correlation was seen with BMI (p=0.09) and was seen in men only. • • • • • • • • • • • • It was demonstrated that the obese patients had significantly higher Mallampati scores (p<0.001) and VAS scores (p<0.006) when compared with their non-obese counterparts. A neck circumference of at least 40cm is significantly higher in the obese subjects than in the non-obese patients (93% versus 36%; p <0.001). Obese patients were 6.5 times (OR 6.49) more likely to have difficult laryngeal exposure (DLE) which was a VAS score of at least 3. Patients with a Mallampati score of 2 or more was associated with DLE when compared to those patients with a score of one (78% versus 24%; p<0.001). They were 10 times more likely to have DLE relative to those with a score of one (OR 10.27). Only the Mallampati scoring (less than 2 versus more than 2) was found to be a significant independent predictor in the multivariate model after logistic regression analysis (p=0.004;OR 9.4).
  • • • Advertisement May 31st E-WEEKLY 5 Patients Died When Tornado Hit Missouri Hospital What's Driving Disruptive Docs? OR Excellence Early-Bird Contest Deadline Extended InstaPoll: When Do You Take a Time Out? News & Notes Same-Day Discharge Risky for Bariatric Surgery What should be the target length of stay for patients undergoing bariatric surgery? Care guidelines updated last year recommended shortening in-hospital recovery times, but leaders in the bariatric community, as well as a new retrospective outcomes study, suggest this could have an adverse impact on patient safety. In a study of nearly 52,000 patients undergoing gastric bypass, those who had the surgery performed outpatient were 13 times more likely to die within 30 days and 12 times more likely to have serious complications than those who remained in the hospital for 2 days, the national average. Even patients who stayed overnight but were discharged less than 24 hours later were more likely to die than those who stayed 2 full days, found a team of Stanford University researchers, who presented their findings at the Annual Meeting of the American Society of Metabolic & Bariatric Surgery (ASMBS) in Orlando, Fla., last week. Overall, the 30-day mortality rate was 0.8% for outpatients, 0.1% for those with inpatient stays of 2 days or more. "Length of stay appeared to be the leading risk factor ahead of age, gender, race, body mass index and obesity-related conditions," says study author John Morton, MD, director of bariatric surgery at Stanford Hospital & Clinics. When the 14th edition of the Milliman Care Guidelines came out last year with the recommendation that hospitals shorten the length of stay for gastric bypass patients as a cost- and resource-saving measure, the ASMBS urged the publisher to rethink the changes, arguing that they "are not evidence-based and if implemented will decrease patient safety." Now the organization is using the Stanford research to reinforce its concerns. "Bariatric surgery is safer than ever, but discharging patients too soon after surgery may be pushing the envelope too far and may have serious consequences," says Dr. Morton, who recommends that each patient be discharged based on his "individual risk profile."