It is the ppt about perioperative anesthetic management of patients with respiratory problems

1. Anesthesia For Patients With
Respiratory Diseases
Agmuas A. (MSC)
DBU 2012 E.C
5/18/2023 1

2. Respiratory Diseases
Obstructive Vs Restrictive
• Obstructive:
Conditions that make it hard to exhale all the air in the lungs
• Restrictive:
Pts will have difficulty fully expanding lungs with air.
Shortness of breath during exertion is the common
symptom.
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3. Obstructive Lung Diseases
• Shortness of breath due to difficulty of exhaling air.
• Damage to lungs or narrowing of lung airways  exhaled air
comes out more slowly than normal.
• Hard to breathe, especially during increased activity or exertion.
• At the end of a full exhalation, an abnormally high amount of air
may still remain in the lungs.
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4. OLD…
• The most common causes of OLD are:
Asthma
COPD (emphysema and chronic bronchitis)
Bronchiectasis
Cystic fibrosis
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5. Restrictive lung diseases
• Pts cannot fully fill their lungs with air
• Most often results from a condition causing stiffness:
In the lungs themselves
The chest wall,
Weak muscles, or
Damaged nerves
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6. RLD…
• Common conditions classified under RLD:
Interstitial lung disease
Sarcoidosis
Obesity
NM disease, such as amyotrophic lateral sclerosis (ALS)
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7. Diagnosis of Respiratory Diseases
• Both OLD & RLD can cause shortness of breath, severe
coughing & chest pain.
• Almost all lung diseases are tested by using a pulmonary
function test (spirometry).
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8. Clinical Spirometry
• Vital Capacity
Largest volume measured after an individual inspires
deeply & maximally to TLC & then exhales completely to
residual volume (RV) into a spirometer.
Suspected of being abnormal if it < 80% of predicted value.
The decreased VC is associated with restrictive disease.
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9. Clinical spirometry…
• Time-Expired Spirogram
After a maximum inspiratory effort, a subject exhales as forcefully
and rapidly as possible, and the volume of gas is called FVC.
Exhaled volume is recorded with respect to time.
Rate of airflow indirectly reflects flow resistance properties of
AW.
When AW obstruction occurs, FVC tends to be < standard VC.
5/18/2023 9

10. Clinical spirometry…
• The FVC is reduced by the same conditions that reduce VC.
• To identify AW obstruction, flow rates are determined by
calculation of volume exhaled during certain time intervals.
• Most commonly measured is volume exhaled in the first
second, called (FEV1).
• FEV 25%-75% --MMEF??
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11. Clinical spirometry…
• FEV1 provides an even better perspective on degree of AWO
when it is expressed as a %age of FVC (FEV1/FVC).
• Normal, healthy subjects can exhale 75%-80% of FVC in the
first second.
• Obstructive airway diseases reduce expiratory flow rates and
therefore reduce FEV1 & FEV1/FVC.
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12. Clinical spirometry…
FEV1/FVC:
• <70% - mild obstruction
• < 60% - moderate obstruction
• <50% severe obstruction
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13. Clinical spirometry…
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14. Asthma
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15. Asthma…
• Chronic lung disease characterized by inflammation &
narrowing of the airways  reversible airflow obstruction
due to constriction of smooth muscle .
• An episodic disease with acute exacerbations interspersed with
symptom-free periods.
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16. Asthma…
• Most attacks are short-lived (for minutes-hrs) & clinically the
patient seems to recover completely after an attack.
• Status asthmaticus: is defined as life-threatening
bronchospasm that persists despite treatment.
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17. Asthma…
• Bronchial wall inflammation- fundamental
component of asthma, and results in:
Mucus hyper-secretion
Epithelial damage, as well as
An increased tendency for airways to constrict.
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18. Pathophysiology of Asthma
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19. 5/18/2023 19

20. Asthma…
• Symptoms are most frequently a combination of
Wheezing , cough, dyspnea
Chest discomfort, eosinophilia
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21. Diagnosis
• FEV1 & arterial blood gas analysis
• Chest radiographs  hyperinflation of the lungs.
Severity FEV1 (%predicted) PaO2 (mmHg) PaCO2 (mmHg)
Mild
(asymptomatic)
65-80 >60 <40
Moderate 50-64 >60 <45
Marked 35-49 <60 >50
Severe (status
asthmaticus)
<35 <60 >50
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22. Treatment for Asthma
• ‘Controller’ treatment
Aims on preventing & controlling bronchial inflammation
Include inhaled & systemic corticosteroids, theophylline &
antileukotrienes.
• ‘Reliever’ treatment
Rescue agents for acute bronchospasm
Reliever treatments include β-adrenergic agonists and anticholinergic
drugs
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23. Pharmacologic agents used in the treatment of asthma
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24. Anesthesia for Asthmatic Patients
• Most well-controlled asthmatics tolerate anaesthesia & surgery.
• The frequency of complications is increased in patients with:
Unstable disease,
Those undergoing major surgery and
Over 50 years
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25. Anesthesia for Asthmatic Pts…
• Poorly controlled asthmatics (current symptoms, frequent
exacerbations or hospital admissions) perioperative risk.
• Elective surgery should take place when the patient’s asthma is
optimally controlled.
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26. Preoperative evaluation
• Timing & goals: assess at least one week before.
 High risk of PO pul. complications procedures.
• Goal: optimization  reduce perioperative pul. complications.
Well-controlled vs poorly controlled asthma
Should not be wheezing at the time of surgery.
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27. Preoperative Evaluation… severity & control
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28. Preoperative evaluation…
• Assess
Disease severity
Effectiveness of current pharmacologic management &
Potential need for additional therapy prior to surgery.
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29. Important History
• Severity of asthma
• Allergies & atopy
• Asthma medication use
• Triggering factors
• Frequency of use of short-
acting beta2 agonist.
• Hx of hospitalizations &/or ED visits
• Hx of intubation with severe attack
• Frequency & most recent use of oral
glucocorticoids
• Recent URI, sinus infection, cough /
fever
• Baseline& current PEF or (FEV1)
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30. P/E & Ix
• P/E: RR, wheezing, signs of lung infection & air movement.
Acute severe bronchospasm  diminished/ absent breath sounds.
• Preoperative testing: well controlled asthma (not steroid-
dependent).
Baseline pulse oximetry value should be noted.
PFT- For moderate to severe asthma …high-risk procedures
Use of asthma medications impacts lab. testing.
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31. Laboratory Testing
• Blood tests: similar to those for pts. without asthma.
• High-dose beta2- agonists  hypokalemia, hyperglycemia &
hypomagnesaemia …preoperative test.
• Oral or high-dose inhaled glucocorticoids  HPA
suppression & adrenal insufficiency.
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32. Preoperative Assessment…
• Exercise tolerance
• Any allergies or drug sensitivities, especially effect of
aspirin or other NSAIDs on asthma.
• Prevalence of aspirin (or other NSAID) induced asthma
is 21% in adult asthmatics, and 5% in paediatric
asthmatics.
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33. Preoperative Assessment…
• Examination is often normal in a well controlled patient, but may
reveal chest hyperinflation, prolonged exp. phase & wheeze.
• Patients with mild asthma rarely require extra treatment.
• For symptomatic asthma, consider additional medication or
treatment with systemic steroids.
• Viral infections are potent triggers of asthma, so postpone elective
surgery if symptoms suggest URTI.
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34. Maintenance Medications
• Continue usual medication up to & including the day of
surgery except of theophylline.
• Supplemental steroids: poorly controlled with high-risk
surgery.
• Usually prednisone (40 mg once daily) for five days.
• IV hydrocortisone (100 mg QID), an alternative.
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35. Perioperative medications used to treat Asthma
Class of drug Examples Perioperative
recommendation
Notes
Beta 2 agonists Salbutamol,terbutaline,
salmeterol
Convert to nebulized preparation High doses may lower K+
Vagolytic drug Ipratropium Convert to nebulized
Inhaled steroids
Beclomethasone,
budesonide, flixotide
Continue with inhaled format If >1500 µg/day of
beclomethasone, adrenal
suppression??
Oral steroids Prednisolone Continue hydrocortisone until
take PO
If >10 mg/day, adrenal
suppression likely.
Leukotriene inhibitor (anti-
inflammatory)
Montelukast, zafirlukast Restart when taking oral
medications
Mast cell stabilizer Disodium cromoglycate Continue by inhaler
Phosphodiesterase inhibitor Aminophylline
Continue where possible Effectiveness in asthma
debated. In severe asthma
consider converting to an
infusion perioperatively.
35
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36. Premedication
• Anxiolytics  reduce bronchospasm.To dry secretions.
• Short-acting beta2 agonist inhaler (2 to 4 puffs) or nebulizer
(albuterol 2.5 mg) 20 to 30 min prior to AW manipulation.
• Sedatives & narcotics …over sedation & resp. depression.
• Midazolam or small doses fentanyl…painful procedures prior
to anesthetic induction (eg, placement of an intra-arterial or
epidural catheter), may be used.
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37. Choice of Anesthetic Technique
• Avoid of tracheal intubation if possible.
• Regional anesthesia
Neuraxial anesthesia
Brachial plexus blocks –paralyze diaphragm phrenic nerve block.
• General anesthesia —mechanical stimulation AW,
suctioning, inhalation of cold anesthetic gases, pulmonary
aspiration of stomach contents.
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38. Induction of Anesthesia
• AW management- A goal (minimize risk of a bronchospasm)
• LMA or mask ventilation vs ETT.
• Anesthetic agents- sufficient depth of anesthesia.
Opioid and/or lidocaine & NMBA.
• Propofol … induction choice.
• Ketamine, etomidate, barbiturates (methehexital ,theopental
• Meperidine, morphine
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39. Maintenance of Anesthesia
• Inhalational agents
• TIVA
• Beta blockers
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40. Drugs considered safe for asthmatics
Induction
Propofol, etomidate, ketamine, midazolam
Opioids Pethidine, fentanyl, alfentanyl
Muscle relaxants
Vecuronium, suxamethonium, rocuronium, pancuronium
Volatile agents
Halothane, isoflurane, enflurane, sevoflurane
40
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41. Ventilation Strategy
• Reduce air trapping
• Lung-protective ventilation strategies:
Controlled hypoventilation with reduced Vt. (e.g, 6 mL/kg)
Reduced RR with longer expiratory time
Reduced inspiratory time (Reduce I:E ratio)
Cautious use of PEEP
Administer inhaled bronchodilator
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42. Intraoperative Bronchospasm
• Identification: Signs of bronchospasm under anesthesia;
Wheezing on chest auscultation
Change in ETCO2: : Upsloping ETCO2 waveform
Severe, decreased, or absent ETCO2 waveform
Decreased tidal volume
High inspiratory pressure
Decreasing oxygen saturation
5/18/2023 42

43. Bronchospasm…Management
• Initially: 100 % oxygen & hand
ventilation.
• Mild: deepening the anesthetic
(propofol or ketamine, inhaled
anesthetic).
• Persistent: short-acting
beta2 agonist.
• More severe :
• Anticholinergics
• Epinephrine , Magnesium sulfate
• Glucocorticoids, Nitroglycerin-rarely
• Heliox – Helium & oxygen???
• Extracorporeal membrane
oxygenation
5/18/2023 43

44. Mx of severe bronchospasm outside OR??
• Start high flow oxygen and gain IV access.
• Nebulised salbutamol 5 mg. May be given continuously at 5–10 mg/hour.
• Metered dose inhaler, preferably with a spacer. 5-10 puffs initially.
• Nebulised ipratropium 0.5 mg (4–6 hrly)
• IV salbutamol if not responding (250 mcg slow bolus then 5–20 mcg/min)
• Hydrocortisone 100 mg IV 6 hourly or prednisolone orally 40–50 mg/day.
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45. • Magnesium sulphate 2g IV over 20 minutes
• Aminophylline 5mg/kg IV followed by infusion may be effective.
• In extremis (decreasing conscious level or exhaustion) adrenaline may be
used: nebuliser 5 ml of 1 in 1,000; IV 10 mcg (0.1 ml 1 : 10,000) increasing
to 100 mcg (1 ml 1 : 10,000) depending on response
 Beware arrhythmias in the presence of hypoxia and hypercapnia
 If IV access is not available, subcutaneous or IM administration (0.5–1 mg) may be
used, though absorption may be unpredictable due to poor perfusion.
45
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46. Postoperative Care
• Patients with severe asthma undergoing major abdominal or
thoracic surgery should be admitted to HDU/ICU.
• Usual medications should be prescribed after surgery.
• Pain relief …major abdominal or thoracic surgery
Regular administration of opioids is the most common technique,
epidural analgesia …the best choice.
• Oxygen for the duration of epidural or opioids administration.
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47. Questions?
5/18/2023 47

48. Chronic Obstructive Pulmonary Disease
(COPD)
Agmuas A.
DBU 2012
5/18/2023 48

49. COPD…
• Most common pulmonary disorder encountered in anesthetic
practice & its prevalence increases with age.
• Strongly associated with cigarette smoking & has a male
predominance.
• Itis characterized by the progressive development of airflow
limitation that is not fully reversible.
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50. COPD…
• Chronic airflow limitation of this disease is due to a mixture
of small & large airway disease (chronic bronchitis
/bronchiolitis) & parenchymal destruction (emphysema).
• Most patients are asymptomatic or only mildly symptomatic,
but show expiratory airflow obstruction upon PFTs.
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51. COPD..
• In many pts, obstruction has an element of reversibility, from
bronchospasm…improvement in response to bronchodilator.
• With advancing disease  low V/Q (intrapulmonary shunt), as
well as areas of high (V /Q ) (dead space).
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52. Chronic Bronchitis
• Defined by presence of a productive cough on most days of 3
consecutive months for at least 2 consecutive years.
Cigarette smoking, air pollutants, exposure to dusts,
Recurrent pulmonary infections, familial factors
• Secretions from hypertrophied bronchial mucous glands &
mucosal edema (inflammation) of AWs airflow obstruction.
5/18/2023 52

53. Chronic Bronchitis…
• “Chronic asthmatic bronchitis”…bronchospasm .
• Recurrent pul. infections are common & often 
bronchospasm.
• RV is increased, but TLC is often normal.
• Intrapulmonary shunting is prominent & hypoxemia is
common.
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54. Chronic Bronchitis…
• In COPD, chronic hypoxemia  erythrocytosis, pul.
hypertension, & eventually  cor-pulmonale
• This combination of findings is often referred to as blue bloater
syndrome, but <5% of pts. with COPD.
• Pts. gradually  chronic CO2 retention less sensitive
ventilatory & may be depressed by O2 administration.
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55. Emphysema
• Irreversible enlargement of the airways distal to terminal
bronchioles & destruction of alveolar septa.
• Mild apical emphysematous changes are a normal, clinically
insignificant & consequence of aging.
• Significant emphysema is more frequently related to cigarette
smoking.
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56. Emphysema…
• Less commonly, occurs at an early age & is associated with a
deficiency of α1 -antitrypsin.
Protease inhibitor that prevents excessive activity of
proteolytic enzymes (mainly elastase);
These enzymes are produced by pulmonary neutrophils &
macrophages in response to infection & pollutants.
• Smoking associated emphysema may be due to similarly way.
5/18/2023 56

57. Emphysema…
• Loss of elastic recoil premature collapse during exhalation
expiratory flow limitation with air trapping & hyperinflation.
• Increases in RV, FRC, TLC & RV/TLC ratio.
• Alveolar–capillary disruption & loss of acinar structure 
decreased DLCO, V/Q mismatch & gas exchange impairment.
5/18/2023 57

58. Emphysema…
• Chronic CO2 retention occurs slowly & generally results in a
compensated respiratory acidosis on blood gas analysis.
• PaO2 is usually normal or slightly reduced.
• Acute CO2 retention is a sign of impending respiratory failure.
5/18/2023 58

59. Emphysema…
• Destruction of pul. capillaries  pulmonary hypertension.
• Pul. HTN is usually low to moderate, rarely > 35-40 mm Hg.
• When dyspneic, pts. often purse their lips to delay closure of
the small airways, which accounts for the term “pink puffers”.
• Most pts. diagnosed with COPD have a combination of
bronchitis & emphysema.
5/18/2023 59

60. Comparative Features of COPD
5/18/2023 60

61. Clinical Features of COPD
• Symptoms include:
Worsening dyspnea,
Progressive exercise intolerance &
Chronic productive cough
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62. History
• Classic symptoms in the chronic bronchitis group:
Productive cough, with progression overtime to intermittent
dyspnea.
Frequent & recurrent pulmonary infections.
Progressive resp. & cardiac failure over time with edema.
5/18/2023 62

63. Hx…
• Classic symptoms in emphysema:
A long history of progressive dyspnea with late onset of
non-productive cough.
Cachexia & respiratory failure.
5/18/2023 63

64. P/E
• Chronic bronchitis (blue bloaters)
Pts may be obese
Frequent cough and expectoration are typical
Use of accessory muscles of respiration is common
Coarse rhonchi and wheezing
Signs of RHF (cor pulmonale)…edema & cyanosis.
5/18/2023 64

65. P/E…
• Emphysema (pink puffers)
Pts may be very thin with barrel chest
Have little or no cough or expectoration
Use of accessory respiratory muscles
Wheezing
Hyper resonant chest
5/18/2023 65

66. COPD…
• Three cardinal symptoms of COPD are
 Dyspnea, chronic cough, and
 Sputum production
• The most common early symptom is exertional dyspnea.
• Less common symptoms include wheezing & chest tightness.
5/18/2023 66

67. COPD…
• Onset is slow & most pts. are symptomatic either with cough
or progressive dyspnoea long before they present to medical
services.
• Therefore a diagnosis of COPD should be considered in all
pts. over forty years old with a significant smoking history.
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68. Treatment
• Designed to relieve existing symptoms & slow dx. progression.
Cessation of smoking
Oxygen administration
Drug therapy: Bronchodilators, Antibiotics, diuretics
• Physical training
• Surgery
5/18/2023 68

69. Preoperative Assessment: Hx.& P/E
• A smoking history, exercise tolerance
• Frequency of exacerbations, hospital admissions & previous
requirements for invasive & non-invasive ventilation.
• Cough & particularly sputum production -independent risk
factor for PO pul. complications in COPD.
• A clear history regarding co-morbid conditions is vital.
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70. Investigations
• Chest X-ray - to exclude active infection & occult
malignancy
• ECG - may reveal right heart disease (right ventricular
hypertrophy or strain)
• Consider echocardiography
• Spirometry is used to clarify diagnosis & assess severity.
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71. GOLD Classification of COPD (post bronchodilator
FEV1)
Stage I: Mild FEV1/FVC <0.70
-FEV1 ≥ 80% predicted
Stage II: Moderate FEV1/FVC<
0.70
-FEV1 50 - 80% predicted
Stage III : Severe FEV1/FVC <0.70
-FEV1 30 - 50% predicted
Stage IV: Very Severe
FEV1/FVC<0.70
-FEV1 <30% predicted
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72. 5/18/2023 72
GOLD 1 (mild), GOLD 2 (moderate), GOLD 3 (severe), GOLD 4 (very severe)

73. Preoperative Optimisation
• Can be divided into four main areas:
 Smoking cessation,
 Optimization of drug therapy,
 Treatment of infection, and
 Respiratory physiotherapy
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74. Preoperative Optimisation…
• Preoperative interventions aimed at correcting;
Hypoxemia, relieving bronchospasm,
Mobilizing & reducing secretions & treating infections may
decrease incidence of POP pul. complications.
• Long-acting bronchodilators & mucolytics should be
continued, including on the day of surgery.
. 5/18/2023 74

75. Intraoperative Management
• Regional anesthesia is often considered preferable to GA.
• High spinal or epidural decrease lung volumes, restrict use
of accessory muscles & produce ineffective cough dyspnea
& retention of secretions.
• Interscalene blocks VS diaphragmatic paralysis
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76. Intraoperative Management
• Preoxygenation, selection of anesthetic agents & general
intraop. mx.
• Bronchodilating anesthetics improves only reversible AWO.
• PPV air trapping, dynamic hyperinflation & elevated
intrinsic PEEP (iPEEP).
• Hyperinflation volutrauma, hemodynamic instability,
hypercapnia & acidosis.
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77. Intraoperative Management…
• Interventions to mitigate air trapping include:
1) More time to exhale (decrease both RR & I:E ratio;
2) Allowing permissive hypercapnia;
3) Applying low levels of extrinsic PEEP;
4) Aggressively treating bronchospasm.
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78. Intraoperative Management…
• Pneumothorax & right HF due to hypercapnia & acidosis 
intraop. hypotension.
• A pneumothorax  hypoxemia, increased PAP, decreasing Vt.
& abrupt CVS collapse unresponsive to fluid & vasopressors.
• Nitrous oxide…bullae & pulmonary hypertension.
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79. Intraoperative Management…
• ABG analysis …intra-abdominal & thoracic procedures.
• Pulse oximetry, direct PaO2, PaCO2 measurement.
• Moderate (Paco2 up to 70 mmHg may be well tolerated in the
short term, assuming a reasonable CVS reserve.
• Hemodynamic support with inotropic agents.
• In pts. with pul. HTN…CVP reflect Rt, ventricular function.
5/18/2023 79

80. Management…
• Extubation: bronchospasm vs respiratory failure.
• Successful extubation:
Adequate pain control, reversal of NMB,
Absence of bronchospasm & secretions, absence of significant
hypercapnia & acidosis & absence of respiratory depression.
• Pts. with an FEV 1 < 50% may require a period of PO ventilation,
particularly following upper abdominal and thoracic operations.
5/18/2023 80

81. Restrictive Pulmonary Disease
• Characterized by decreased lung compliance.
• Lung volumes are typically reduced, with preservation of
normal EFR.
• Thus, both FEV1 & FVC are reduced, but the FEV1 /FVC
ratio is normal.
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82. RLD…
• Include many acute & chronic intrinsic pul. disorders &
extrinsic (extrapulmonary) disorders (pleura, chest wall,
diaphragm, or NM function).
• Reduced lung compliance increases WOB  rapid, but
shallow, breathing pattern.
• Respiratory gas exchange is usually maintained until the
disease process is advanced.
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83. Acute Intrinsic Pulmonary Disorders (AIPD)
• Include pulmonary edema (including acute respiratory
distress syndrome [ARDS]), infectious pneumonia &
aspiration pneumonitis.
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84. Acute Respiratory Distress Syndrome
• ARDS is commonly encountered in critical care population &
is associated with a high mortality of between 27% and 45%.
• Diagnosed according to the Berlin definition & is
characterized as mild, moderate, or severe depending on
PaO2/FIO2 ratio.
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85. Berlin Definition of ARDS…
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86. ARDS…
• Potential causes of ARDS can be classified as;
Pulmonary (pneumonia, pulmonary contusions, etc.) and
Extra-pulmonary (including burns, trauma, etc.).
• Pneumonia & non-pulmonary sepsis are the leading causes.
5/18/2023 86

87. ADRS…
• End result of a complex interplay between various inflammatory
mediators  diffuse alveolar damage, non-cardiogenic pulmonary
edema, surfactant dysfunction & atelectasis.
• Three overlapping phases ;
• Initially, exudative (or acute) phase  hypoxaemia & a reduction in
pulmonary compliance (alveolar flooding with protein-rich fluid).
5/18/2023 87

88. ARDS…
• Proliferative (or subacute) phase: from day 5 onwards with
further reduction in lung compliance & continued hypoxemia
… fibroproliferation & microvascular thrombus formation.
• Fibrotic or chronic phase, characterized by widespread fibrosis
& lung remodelling which may be irreversible.
5/18/2023 88

89. Management of ARDS
• Good supportive care & management of underlying causes of
illness of all critically unwell patients.
• Usually mandates intubation & mechanical ventilation.
• Previously, ICU practitioners attempted to ventilate with high
PP until normal gas exchange was achieved.
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90. ARDS Mx…
• Repetitive, cyclical lung overstretching & collapse generate
local & systematic inflammation & contribute to multi-organ
failure & death.
• PEEP is key  collapse of alveoli reducing shunt & V/Q
mismatch.
• An optimal level of PEEP not identified.
5/18/2023 90

91. ARDS Mx…
High-frequency oscillation ventilation (HFOV)
• Now infrequently used in adults, (HFOV) delivers extremely
low VT (1–2 ml kg−1) at very high rates (3–15 breaths/second).
• This strategy is based on the theory that low VTs and higher
PEEP limit ventilator-associated lung injury.
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92. ARDS Mx…
• Prone positioning
• Extracorporal membrane oxygenation (ECMO)
• Fluid management: Conservative approach VS liberal strategy
Use of albumin
• Nutrition
• Pharmacotherapy: Steroids
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93. Pulmonary Edema
• Results from transudation of fluid, first from pul. capillaries 
interstitial spaces & then from interstitial spaces  alveoli.
• Fluid in interstitial space & alveoli is collectively referred to as
extravascular lung water.
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94. PE…
• Movement of water across pul. capillaries is similar to what occurs
in other capillary beds & can be expressed by Starling equation:
 Q = net flow across capillary; Pc′ & Pi = capillary & interstitial
hydrostatic pressures,
 πc′ & πi = capillary & interstitial oncotic pressures,
 K = filtration coefficient related to effective capillary surface area per
mass of tissue;
 σ = reflection coefficient that expresses the permeability of the
capillary endothelium to albumin.
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95. PE…
• Albumin is particularly important in this context.
• A σ =1 implies that endothelium is completely impermeable to
albumin, whereas “0” indicates free passage of albumin. &
other particles/molecules.
• Net amount of fluid that normally moves out of pul. capillaries
is small (about 10–20 mL/h in adults) & is rapidly removed by
pul. lymphatics  central venous system.
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96. Pulmonary Edema..
• Stage I: Only interstitial PE is present.
As pulmonary compliance decrease pts. often  tachypneic.
X-ray: increased interstitial markings & peribronchial cuffing.
• Stage II: Fluid fills interstitium & begins to fill alveoli, initially
confined to angles b/n adjacent septa (crescentic filling).
Near-normal gas exchange may be preserved.
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97. PE…
• Stage III: Many alveoli completely flooded & no longer contain gas.
Flooding is most prominent in dependent areas.
Flooded alveoli  intrapul. Shunting Hypoxemia & hypocapnia
• Stage IV: Marked alveolar flooding spills into the airways as froth.
Both shunting & AWO compromised gas exchange 
progressive hypercapnia & severe hypoxemia.
97

98. 5/18/2023 98

99. Causes of Pulmonary Edema
• Increase in net hydrostatic pressure across capillaries (hemodynamic
or cardiogenic PE) or
• Increase in permeability of alveolar–capillary membrane (increased
permeability edema or non-cardiogenic PE).
• Protein content of the edema fluid can also help differentiate the two.
• Fluid due to hemodynamic edema has a low protein content, whereas
that due to permeability edema has a high protein content.
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100. Causes of PE…
• Less common causes of edema include:
Prolonged severe airway obstruction (-ve pressure PE),
Sudden re-expansion of a collapsed lung, high altitude
Pulmonary lymphatic obstruction & severe head injury.
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101. Less common causes of PE…
• PE associated AWO: from an increase in transmural pressure
across pul. capillaries associated  markedly -ve Pi.
• Neurogenic PE appears to be related to a marked increase in
sympathetic tone severe pulmonary hypertension.
• The latter can disrupt the alveolar–capillary membrane.
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102. Preoperative Considerations
• Reduced lung compliance: primarily due to an increase in EV
lung water (increase in pul. Pc or pul. capillary permeability).
• Increased pressure occurs with left ventricular failure.
• Fluid overload & increased permeability present with ARDS.
• Localized or generalized increases in permeability also occur
following aspiration or infectious pneumonitis.
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103. Anesthetic Considerations
• Acute pulmonary disease…spare elective surgery.
• Emergency procedures…oxygenation & ventilation
should be optimized preoperatively.
• Fluid overload…diuretics
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104. Anesthetic Considerations…
• Vasodilators & inotropes… heart failure.
• Drainage of large pleural effusions.
• Massive abdominal distention …NGT/drainage of ascites.
• Persistent hypoxemia may require mechanical ventilation.
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105. Anesthetic Considerations…
• Pts. with acute pulmonary disorders (ARDS, cardiogenic PE,
or pneumonia are critically ill.
• Anesthetic mx. should be a continuation preop. ICU care.
• High FIO2 & PEEP may be required.
• Decreased lung compliance high PIP during PPV &
increases risk of barotrauma & volutrauma.
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106. Intraoperative Management…
• Reduce VT (4–6 mL/kg) & increase RR (14–18 breaths/min).
• AW pressure should generally not exceed 30 cm H2O.
• Airway pressure release ventilation (inverse ratio ventilation)
may improve oxygenation in the ARDS patient.
• Anesthesia machine vs ICU ventilator.
• Aggressive hemodynamic monitoring is recommended.
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107. Chronic Intrinsic Pulmonary Disorders
• Are also often referred to as interstitial lung diseases.
• Generally characterized by an insidious onset, chronic
inflammation of alveolar walls & peri-alveolar tissue &
progressive pul. fibrosis.
• Inflammatory process: confined to lungs or part of a
generalized multiorgan process.
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108. Chronic Intrinsic Pulmonary Disorders…
• Causes include hypersensitivity pneumonitis from
occupational & environmental pollutants, drug toxicity,
radiation pneumonitis, idiopathic pulmonary fibrosis,
autoimmune diseases & sarcoidosis.
• Chronic pulmonary aspiration, oxygen toxicity & severe
ARDS can also produce chronic fibrosis.
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109. Preoperative Considerations
• Patients typically present with dyspnea on exertion & sometimes a
nonproductive cough.
• Symptoms of cor-pulmonale…only with advanced disease.
• P/E may reveal fine (dry) crackles over lung bases & in late stages,
evidence of right ventricular failure.
• Chest X-ray progresses from a “ground-glass opacity” reticulo-
nodular markings & finally  “honeycomb” appearance.
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110. Anesthetic Considerations…
• ABG usually show mild hypoxemia with normocarbia.
• PFTs: restrictive ventilatory defect, reduced DLCO.
• Treatment: abating disease process & preventing further
exposure to causative agent (if known).
• Glucocorticoid & immunosuppressive …idiopathic pul.
fibrosis, autoimmune disorders & sarcoidosis.
• Chronic hypoxemia… oxygen therapy.
5/18/2023 110

111. Anesthetic Considerations
• Preoperative: degree of pul. impairment & underlying ds.
process.
• Potential involvement of other organs.
• Hx. of dyspnea on exertion (or at rest) , PFTs & ABG analysis.
• A VC < 15 mL/kg (severe dysfunction), (normal, >70 mL/kg).
• A chest radiograph is helpful in assessing disease severity.
5/18/2023 111

112. Anesthetic Considerations…
• Management is complicated by a predisposition to hypoxemia
& need to control ventilation to ensure optimum gas exchange.
• Reduced FRC (oxygen stores)  rapid hypoxemia ff induction.
• May be more susceptible to oxygen-induced toxicity
(bleomycin) FIO2 should be kept minimum (achieving Spo2
>88% to 92%).
5/18/2023 112

113. Anesthetic Considerations…
• High PIP  increase risk of pneumothorax & should prompt
adjustment of the ventilatory parameters.
• Severe restrictive diseas … using an I:E ratio of 1:1 (or even
an inverse ratio ventilation) & dividing MV to a higher RR
(10–15 bpm) maximize inspiratory time per VT &
minimize peak & plateau ventilatory pressures.
5/18/2023 113

114. Extrinsic Restrictive Pulmonary Disorders
• Alter gas exchange by interfering with normal lung expansion.
Pleural effusions, pneumothorax, mediastinal masses,
Kyphoscoliosis, pectus excavatum, NM disorders &
Increased IAP (ascites, pregnancy/bleeding) marked obesity.
• Anesthetic considerations are similar to those discussed for
intrinsic restrictive disorders.
5/18/2023 114

115. Anesthesia for Patient with Pulmonary
Tuberculosis
Agmuas A.
2012, DBU
5/18/2023 115

116. Introduction
• TB is an infectious disesase usually caused by MTB bacteria.
• MTB spread: airborne transmission of small droplets (0.5-5 μm).
• Usually, infection occurs b/n prolonged household contacts.
• Exposure to only a few bacteria is needed to establish infection.
• Primary site of infection is upper lobe of lung …high oxygen
tension,,, Ghon focus.
5/18/2023 116

117. Introduction…
• Bacteria invade & replicate within macrophages.
• Followed by a T- cell mediated response, which walls off
infected cells to form a granuloma.
• Bacteria within granuloma can become dormant latent
infection.
• At this stage, patient will be asymptomatic, but may show a
positive response to a tuberculin skin test.
5/18/2023 117

118. Introduction…
• Factors that increase likelihood of progression to active disease
include:
Time from exposure (most common in 1st year)
Age of patient (younger than five years old),
Competency of the immune system.
5/18/2023 118

119. Patients may present in a number of ways:
• Pul. disease is most common
 a chronic productive cough & hemoptysis.
Lymph nodes enlargement bronchial compression with
localized wheeze.
Hematogenous spread  widespread lung infection
(miliary TB).
5/18/2023 119

120. Presentation…
• Constitutional symptoms secondary to production of proinflammatory
cytokines are commonly seen.
Fever, night sweats, loss of weight, or failure to thrive in children.
• Activation of T-cell-mediated immunity Hypersensitivity
Erythema nodosum, phlyctenular conjunctivitis & Poncet’s dx.
• Extrapulmonary disease
Lymphadenitis (scrofula), bones and joints, abdominal TB &
meningitis.
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121. Diagnosis
• Traditionally: visualising acid-fast bacilli on sputum.
• Newer technology: such as Xpert® M. TB/resistance to rifampicin or
GeneXpert®.
 Much quicker results (within 2 hrs).
• Children: sxs of TB, +ve contact & a +ve tuberculin skin test
(Mantoux®).
• T cell interferon-γ (IFN-γ) release assays, which measure # of IFN-γ-
secreting T-cells, … alternative to tuberculin skin test to detect infection.
5/18/2023 121

122. Treatment
• Cornerstone is directly observed treatment (DOT) for at least
six months.
• 1st -line tx: rifampicin, isoniazid (INH), ethambutol &
pyrazinamide.
• Fixed dose combinations help to reduce pill burden.
• Steroids are given for six weeks in cases of TB meningitis,
pericarditis & AWO from lymph node compression.
5/18/2023 122

123. Treatment…
• Some of serious S/E, may have impact on anesthetist.
Rifampicin may thrombocytopenia (high doses).
INH may  sensory neuropathy, …regional blocks??
• This complication can be prevented by adding pyridoxine
(vitamin B6 ) in high-risk cases.
• Ethambutol has the potential to cause optic neuritis.
Not routinely given to children.
5/18/2023 123

124. Treatment…
• Drug-induced hepatitis is a worrying complication.
• Ant-TB plus concomitant RVI therapy a mild liver enzymes
elevation.
• However, symptomatic hepatitis has a mortality of almost 5%,
& requires immediate halting of TB drugs, with careful re-
introduction under specialist care.
5/18/2023 124

125. Treatment…
• Wherever possible, surgery should be avoided during this
period.
• MDR and XDR TB require extended treatment for up to two
years with four or five drugs, depending on resistance patterns.
• Besides the added cost of treatment, there is also an increased
risk of life-threatening side effects.
5/18/2023 125

126. Anesthetic Implication
• The patient of TB may be require anesthesia for:
Diagnostic procedures (Lymphnode biopsies,
Brochoscopies),
Complications of TB (Hydrocephalus, Intestinal obstruction
requiring anesthesia) & elective /emergency surgeries.
5/18/2023 126

127. Anesthetic Implication…
• Three major implications for the anethetist:
• 1. General state of pt’s health & impact of the disease on organ
function.
• The tx. that pt. is receiving & considerable potential for drug
interactions.
• The risk of transmission of TB to staff & other patients.
5/18/2023 127

128. Patient Assessment
• The patient may be acutely ill, either with TB or a superadded
infection.
• Alternately, he or she may be chronically ill, malnourished &
frequently anemic.
• Long-standing TB. CLD with bronchiectasis & fibrosis.
• A full history, examination & relevant investigations.
5/18/2023 128

129. Drug Interactions…
• Drug interactions are mostly due to pharmacokinetic changes
full induction of liver enzymes.
• Rifampicin is responsible for most observed drug interactions.
• It is a potent inducer of CYP450 system  Increased
metabolism.
• CYP3A4 is also found in small intestine oral drugs more affected.
5/18/2023 129

130. Drug Interactions
• On the other hand, INH is a CYP450 inhibitor.
• However, due to differential effect on specific isoenzymes,
these two drugs do not simply cancel each other out.
• Greater potential for a drug interaction when a patient is also
taking ARI drugs & specifically protease inhibitors.
5/18/2023 130

131. Induction Agents
• TB therapy is unlikely to have an effect on a single induction
dose.
• However increased metabolism may be important in TIVA, with
a greater potential for awareness.
• While there is no evidence to support this, one should be
mindful of this risk & consider use of depth of anesthesia
monitoring in pts.
5/18/2023 131

132. Local Anesthetics
• As they exert their action primarily at the site of injection, LA
drugs are still likely to be effective & help to avoid many of the
other drug interactions seen with opiates.
• Increased metabolism may result in a decreased risk of local
anesthetic toxicity.
5/18/2023 132

133. Volatile Anesthetics
• Halothane is metabolized via isoenzyme CYP2E1 to trifluroacetic
acid.
• This molecule has potential to act as a hapten to trigger an immune
mediated hepatitis.
• CYP2E1 is induced by INH.
• Thus patients on anti-TB therapy are potentially at increased risk of
halothane hepatitis.
• The minimal metabolism of the newer volatile agents makes them a
better choice.
5/18/2023 133

134. Neuromuscluar Blocking Drugs
• Unless liver dysfunction results in decreased pseudocholinesterase
levels, effect of suxamethomium is unchanged.
• Similarly cisatracurium (organ independent metabolism) and
pancuronium (renal excretion) are minimally affected by TB therapy.
• While no trials specifically look at interactions with TB treatment, it
has been shown that effect of vecuronium is prolonged by cimetidine,
an enzyme inhibitor, and shortened by phenytoin enzyme induction.
5/18/2023 134

135. NMB…
• Rocuronium is less affected but resistance to muscle blockade
has been shown with carbamazepine.
• Streptomycin may potentiate effects of non-depolarising
agents.
• NDNMD should, therefore, be titrated to response, with
frequent evaluation using a nerve stimulator.
5/18/2023 135

136. Analgesics
• While metabolism of morphine predominantly involves phase II
reactions via UDP-glucuronosyltransferases, anti-TB therapy seems
to have an effect.
• A loss of analgesic effect of oral morphine has been demonstrated
following pretreatment with rifampicin.
• Fentanyl & alfentanil are both extensively metabolised by CYP450
3A4, therefore, also show potential for a shortened duration of
action.
• The metabolism of codeine is interesting.
5/18/2023 136

137. Analgesics…
• The analgesic effect of codeine is mediated through its
metabolism to morphine via CYP450 2D6.
• One may, therefore, expect a greater analgesic effect following
enzyme induction.
• However, it is also metabolized to inactive norcodeine via
isoenzyme 3A4, resulting in an overall decreased effect.
• The effect of tramadol is unchanged.
5/18/2023 137

138. Analgesics…
• Of NSAIDs, effect of diclofenac is decreased with rifampicin, while
that of ibuprofen is unchanged, making it a safer option.
• Analgesia should therefore be titrated to effect with the potential to
require more frequent dosing.
• Therefore, the choice of anesthetic depends on patient, procedure &
severity of disease.
• Regional anesthesia is often preferred in patients with CLD & to
avoid potential drug interactions.
• Hepatotoxic drugs must be avoided.
5/18/2023 138

139. 5/18/2023 139

140. Spread of Tuberculosis
• To immunocompromised patients & to theatre staff is an area
of concern.
• Airway during intubation particular risk for anesthetists.
• Children are less likely to have cavitary dx. & are, therefore,
less infectious.
5/18/2023 140

141. Spread of Tuberculosis…
• Delay elective surgery until patient is no longer infectious.
On treatment for 2-3 weeks, clinically getting better &
having had three negative sputa on different days.
• While practically, the third criterion might be difficult to
achieve, the first two should certainly be followed.
5/18/2023 141

142. 5/18/2023 142

143. Spread of Tuberculosis…
• Elective cases…last case of day to allow decontamination.
• Transfer pt. wearing an N95® mask & brought straight to OR.
• Minimize OR inside traffic to essential staff.
• Theatre staff must wear N95® masks.
For high-risk procedures, intubation & bronchoscopy.
Adequate anesthesia & muscle relaxation  no cough on
intubation.
5/18/2023 143

144. Spread of Tuberculosis…
• Bacterial filter placed both by pt’s. airway & on the expiratory
limb of the circuit.
• These should be able to filter more than 99.97% of particles
greater than 0.3 μm.
• While not specifically advocated by ASA, it would be good
practice to sterilize the circuits after such a case.
5/18/2023 144

145. THANK YOU!!
5/18/2023 145