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بسم الله الرحمن الرحيم رب اشرح لي صدري ويسر لي امري واحلل عقده من لساني يفقهو قولي
BARIATRIC SURGERYPART-1 Hosam Atef ; MD SUEZ CANAL UNIVERSITY ANESTHESIA & ICU
BARIATRIC SURGERY • USA bariatric surgeries /year: • 16 200 (1992) • 220 000(2008). • 344 000 worldwide (2008)
DEFINITIONS • BODY MASS INDEX BMI ( Quetelet’s Index): WEIGHT(kg)/HEIGHT (m2)
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
COMORBID DISEASE PREVALENCE IN 1,210 PATIENTS FOR BARIATRIC SURGERY
COMORBID DISEASE PREVALENCE IN 1,210 PATIENTS FOR BARIATRIC SURGERY
Comorbidities on mortality and complications after gastric bypass no major comorbid disease • Hypertension • Diabetes • Venous stasis disease • pseudotumor cerebri • OSA and/ or OHS 1 or +
Comorbidities on mortality and complications after gastric bypass
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.
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
PULMONARY FUNCTION • Reduced compliance of lung and chest wall. • Reduced lung volume. • Increased respiratory resistance. • Increased work of breathing.
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.
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.
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
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
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 or BiPAP
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
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.
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.
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
POTENTIALLY LIFE –THREATENING SLEEP APNEA IS UNRECOGNIZED WITHOUT AGGRESSIVE EVALUATION. • OSA is grossly underdiagnosed. • Clinical evaluation misses a % of patients with OSA. • Mandatorytesting with Polysomnography
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.
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 7- Increased incidence of sudden and unexplained death
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
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
Cardiovascular evaluation and management of severely obese patientsPaul Poirier ,et al .Circulation 2009
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.
CARDIORESPIRATORY FITNESS AND SHORT TERM COMPLICATIONS AFTER BARIATRIC SURGERY
AIRWAY ASSESSMENT OBESE= PREDICTABLE DIFFICULT INTUBATION • OSA • SHORT + FAT NECK • Airway claims • intubation = 37% obesity • Extubation 67% - 28% OSA.
Obstructive sleep apnea is not a risk factor for difficult intubation in 180 morbidly obese patients AIRWAY ASSESSMENT Risk factors : • Mallampati Score > 3 • male gender
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
Reverse Trendelenburg = proclive
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 Cushing’s Syndrome)
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 .
HOME MESSAGES • Exponential increase in Bariatric surgery worldwide. • Comorbidities affect outcome. • Pre-operative evaluation is Multidisplinary. • Anesthetic evaluation & preparation. • Clinical pathway.