This document discusses bariatric surgery and provides information about preoperative evaluation and management of obese patients undergoing such procedures. It defines terms like BMI, ideal body weight and comorbidities associated with obesity. It emphasizes the importance of a multidisciplinary preoperative assessment, including evaluation of pulmonary, cardiac, endocrine and airway status. Risk scoring systems to predict mortality are presented. Intraoperative management challenges like difficult intubation are also addressed.

1. ‫الرحيم‬ ‫الرحمن‬ ‫ا‬ ‫بسم‬
‫لي‬ ‫ويسر‬ ‫صدري‬ ‫لي‬ ‫اشرح‬ ‫رب‬
‫لساني‬ ‫من‬ ‫عقده‬ ‫واحلل‬ ‫امري‬
‫قولي‬ ‫يفقهو‬

2. BARIATRIC SURGERY
PART-1
Hosam Atef ; MD
SUEZ CANAL UNIVERSITY
ANESTHESIA & ICU
2

3. BARIATRIC SURGERY
USA bariatric surgeries /year:
 16 200 (1992)
 220 000 (2008).
 344 000 worldwide (2008)

4. DEFINITIONSBODY MASS INDEX BMI ( Quetelet’s Index):
WEIGHT(kg)/HEIGHT (m2)
BMI
SEVERE OBESITY 35-39.9
MORBID OBESITY > 40
SUPER OBESITY > 50
WEIGHT FEMALE MALE
IDEAL 19.1-25.8 20.7-26.4
MARGINAL OVERWEIGHT 25.9-27.2 26.5-27.8
OVERWEIGHT 27.3-32.3 27.9-31.3
OBESE 32.4-34.9 31.4-34.9

5. IDEAL BODY WEIGHT
 Ideal Body Weight: IBW (Lorentz) :
IBW = X + 0,91 (height in cm - 152,4)
Female : X = 45, 5
Male : X = 50
More easy to remember
IBW (kg) = Height (cm) - 100 in MALE
IBW (kg) = Height (cm) - 110 in FEMALE

6. OBESE PATIENT = RISKS

7. COMORBID DISEASE PREVALENCE IN 1,210 PATIENTS
FOR BARIATRIC SURGERY
MUSCULOSKELETAL
ARTHRITIS 47%
VENOUS STASIS
DISEASE
3%
HYPERTENSION 43% HERNIA 2%
SLEEP APNEA 36% FLUID RETENTION 1%
DIABETES MELLITUS 21%
SUPRAVENTRICULAR
TACHYCARDIA < 1%
RESPIRATORY DISORDERS 16% CHF < 1%
GERD 1 1% LYMPHEDEMA < 1%
HYPERLIPIDEMIA 5% INCONTINENCE <1%
DEPRESSION 4%

8. COMORBID DISEASE
BURDEN
PATIENTS %
NO COMORBIDITIES 137 14
1 COMORBID DISEASE 263 22
2 COMORBID DISEASE 454 38
3 COMORBID DISEASE 284 23
4 OR MORE COMORBID DISEASE 71 6
COMORBID DISEASE PREVALENCE IN 1,210 PATIENTS
FOR BARIATRIC SURGERY

9. • Hypertension
• Diabetes
• Venous stasis disease
• pseudotumor cerebri
• OSA and/ or OHS
no major comorbid disease
1 or +
Comorbidities on mortality and complications after gastric bypass

10. 32 + 6 BMI 0.001 35 + 8
0.2% Mortality 0.0032 2.3%
1.2% Leak rate 0.0032 4.1%
1.4% Surgical Infection 0.0133 3.9%
68% Excess weight loss 0.001 62%
Comorbidities on mortality and complications after gastric bypass

11. INDICATIONS/CONTRAINDICATIONS
1- Individuals with BMI > 40 Kg/m2 who have failed
conventional weight-control programs.
2- Individuals with a BMI between 35 and 39.9 kg/m2 who
have high risk health problems affecting lifestyle ( i.e,
employment or mobility)
CONTRAINDICATIONS:
 1- Severe mental illness resulting in psychosis.
2- Substance abuse.
3- Major organ failure.

12. PREOPERATIVE ASSESSMENT
=
Multidisciplinary
Special Bariatric Surgeon
Anesthesiologist
Medical
Cardiology
Pulmonary
Diabetology
Endoscopist
Psychiatry
Dietitian
Plastic Surgeon
• PULMONARY
- Restrictive lung disease
-OSA
-OHS
• CARDIAC
-HTN/CAD/CHF
-Dysrhythmias
-cardiomyopathy
• DM/Thyroid/Adrenal
• AIRWAY
•Vascular assessment

13. PULMONARY FUNCTION
 Reduced compliance of lung and chest wall.
Reduced lung volume.
Increased respiratory resistance.
Increased work of breathing.

14. RESPIRATORY SYSTEM
Dyspnea with exertion.
Significant impairement of pulmonary function ,
often with few symptoms.
Reduction in lung volumes  atelectasis, airway
closure  hypoxia.
Reduction of functional residual capacity rapid
desaturation during apnea at anesthesia induction.

15. PRE OPERATIVE PULMONARY EVALUATION
Preoperative pulmonary function tests are indicated for
patients with
1- documented pulmonary problems.
2- limited performance status because of dyspnea.
3- BMI > 60 kg/m2.
Arterial blood gas hypoventilation in severely obese
patients.
Identify risk for postoperative hypoxia.
Facilitate postoperative respiratory care.

16. PULMONARY EVALUATION
Forced vital capacity varies inversely with BMI.
Patients with very high BMI , even when
asymptomatic will have major reductions in lung
function
Patients with preoperative pulmonary impairement
Significant risk for hypoxia during the immediate
postoperative period  Bi-level positive airway pressure
in recovery room preserve oxygenation
No evidence of gastric pouch problems
related to its use

17. OBSTRUCTIVE SLEEP APNEA ( OSA)
75 % of PATIENTS
The prevalence increases with BMI.
OSA is an independent risk factor
for metabolic syndrome ( impaired glucose tolerance-insulin
resistance and dyslipidaemia)
for all-cause mortality

18. OBSTRUCTIVE SLEEP APNEA ( OSA)
Detailed clinical history is mandatory.
Symptoms: - Heavy snoring
- Witnessed apnea.
- Excessive daytime somnolence.
- Lack of restful sleep.
Questionnaire: STOP, Berlin, ASA Check list.
 Patients with suspected OSA  preoperative sleep study
(Polysomnography)& titration of CPAP.
Consequence of OSA can be reversed by CPAP

19. STOP QUESTIONNAIRE
STOP Questionnaire is concise and easy –to use screening tool for OSA.
1-Do you snore loudly?
2- Do you often feel tired , fatigued or sleepy during day time?
3- Do you have or are you being treated for high blood pressure?
4- Has any one observed you stop breathing during sleep?
Combined with
 BMI
 age
 neck size & gender,
STOP = high sensitivity
especially for patients
with moderate to severe OSA
19

20. Validation of the Berlin Questionnaire and American Society of
Anesthesiologists Checklist as screening tools for obstructive
sleep apnea in surgical patients
The Berlin questionnaire and ASA checklist
demonstrated a moderately high level of sensitivity
for OSA screening.
STOP Questionnaire and the ASA checklist were able
to indentify the patients who were likely to develop
postoperative complications.

21. OBSTRUCTIVE SLEEP APNEA ( OSA) & POLYSOMNOGRAPHY
Routine preoperative PSG
cost effective
lacking improved outcome
=> not part of ASA practice guidelines for the
perioperative management of patients with OSA.
ASA practice guidelines for the perioperative management
of patients with obstructive sleep apnea.
A referral for PSG study should
be individualized.

22. POTENTIALLY LIFE –THREATENING SLEEP APNEA IS
UNRECOGNIZED WITHOUT AGGRESSIVE EVALUATION.
Era 1= OSA evaluation based on clinical parameters.
Era2= Mandatory OSA evaluation for all patients

23. POTENTIALLY LIFE –THREATENING SLEEP APNEA IS
UNRECOGNIZED WITHOUT AGGRESSIVE EVALUATION.
OSA is grossly underdiagnosed.
Clinical evaluation misses a % of patients with OSA.
Mandatory testing with Polysomnography

24. CPAP or BiPAP
DURATION
EFFECT
2 weeks correct abnormal ventilatory drive in obese
hypercapneic patients
3 weeks improves left ventricular ejection function
in patients with CHF
4 weeks
reduce HR, BP & 35% increase in EF in
patients with CHF.
4- 6 weeks reduce tongue volume & increase
pharyngeal space
8 weeks improved morning hypertension
3-6 months reduced pulmonary hypertension
24

25. PREOPERATIVE SMOKING HABITS AND
POSTOPERATIVE PULMONARY COMPLICATIONS
Smoking is a proven risk factor for postoperative
pulmonary complications.
The risk declines with cessation of smoking for 8
weeks before surgery.
Most bariatric programs insist on abstinence from
smoking before-hand.

27. CARDIAC EVALUATION
Cardiac abnormalities associated with morbid obesity
include:
1- Systemic hypertension. 8- Ischemic heart disease
2- cardiac hypertrophy. 9- Cardiac arrhythmias
3- diastolic dysfunction 10- Deep vein thrombosis.
4- Frank systolic dysfunction with cardiomyopathy.
5- Pulmonary hypertension 11 - Pulmonary embolism
6- Congestive heart failure. 12 - Poor exercise capacity

28. CARDIAC EVALUATION
Cardiac evaluation can be difficult to ascertain.
Clinical history  limited mobility.
Clinical examination  muffled heart sounds.
 short thick neck  conceal JVP
 SEDENTARY LIFE  peripheral edema.
Functional capacity 4 METS =climbing a flight of stairs
=moderate functional capacity.
The Revised Cardiac risk is commonly used to assess
cardiac risk in patients undergoing non cardiac surgery

29. Derivation and prospective validation of a simple index for
prediction of cardiac risk of major non cardiac surgery
1 High risk surgery
2 IHD.
3 CHF.
4 Cerebrovascular disease.
5 IDDM
6 Renal insufficiency.
IF YES = 1 POINT/ITEM
SCORE RISK
0 0.4%
1 0.9%
2 6.6%
3 11%

30. Cardiovascular evaluation and management of
severely obese patients
Paul Poirier ,et al .Circulation 2009

31. CARDAIC EVALUATION
 Unknown or limited exercise tolerance or with any
significant co-morbidity  Cardiopulmonary
exercise testing( CPEX).
 Unable to exercise  cardiologist for alternative
provocative cardiac testing.

32. CARDIORESPIRATORY FITNESS AND SHORT TERM
COMPLICATIONS AFTER BARIATRIC SURGERY
32

33. AIRWAY ASSESSMENT
OBESE= PREDICTABLE DIFFICULT INTUBATION
OSA
SHORT + FAT NECK
Airway claims
intubation = 37% obesity
Extubation 67% - 28% OSA.

34. Obstructive sleep apnea is not a risk factor for difficult intubation in
180 morbidly obese patients
Risk factors :
 Mallampati Score > 3
 male gender
AIRWAY ASSESSMENT

35. AIRWAY MANAGEMENT
Optimal positioning;
- Ramped position by placing blankets under the patient’s
upper body.
- 25-30 reversed Trendelenburg, head up or the near
sitting position
 Availability of different airway
management options

36. Reverse
Trendelenburg =
proclive

37. VASCULAR ACCESS

38. ENDOCRINE FUNCTION
15 -20% of morbidly obese patients have type 2
diabetes.
Glucose control requires close preoperative attention.
Hyperglycemia (> 220 mg/dl) inhibits many important
functions of polymorphonuclear leucocytes.
Good preoperative glycemic control in terms of HbA1c
below 7% is associated with a reduced infection risk .
Specialist consultation will be necessary.
Thyroid function tests ; Adrenal function tests ( if

39. SCORING SYSTEMS
Obesity Surgery Mortality Risk Score ( OS-MRS):
Validated scoring system specific to obese patients
undergoing bariatric surgery ( 1 point for each)
 1- BMI > 50 kg/m2. 2- Male gender.
 3- Systemic hypertension. 4- Risk factors for pulmonary embolism.
 5- Age > 45
. SCORE RISK MORTALITY
0-1 LOW 0.31%
2-3 INTERMEDIATE 1.9%
4-5 HIGH 7.56%

40. CLINICAL PATHWAY

41. CLINICAL PATHWAY

42. HOME MESSAGES
Exponential increase in Bariatric surgery worldwide.
Comorbidities affect outcome.
Pre-operative evaluation is Multidisplinary.
Anesthetic evaluation & preparation.
Clinical pathway.
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