Presentation on theme: "Dr Hany Fawzi Senior Specialist- Anesthesia Department Rashid Hospital & Trauma Center 7 March 2013."— Presentation transcript:
Dr Hany Fawzi Senior Specialist- Anesthesia Department Rashid Hospital & Trauma Center 7 March 2013
BARIATRIC SURGERY USA bariatric surgeries /year: 16 200 (1992) 220 000 (2008). 344 000 worldwide (2008) Schumann R,Best practice & Research Clinical Anaesthesiology 2010
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
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 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 Benotti P.Surg Obes Relat Dis 2006 COMORBID DISEASE PREVALENCE IN 1,210 PATIENTS FOR BARIATRIC SURGERY
Hypertension Diabetes Venous stasis disease pseudotumor cerebri OSA and/ or OHS no major comorbid disease 1 or + Jamal MK Surg Obes Relat Dis.2005 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.
PULMONARY FUNCTION Reduced compliance of lung and chest wall. Reduced lung volume. Increased respiratory resistance. Increased work of breathing. Koening SM.Am J Med Sci 2001
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. Koening SM.Am J Med Sci 2001
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. Koening SM.Am J Med Sci 2001 Benotti P.Surg Obes Relat Dis 2006
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***. Santana AN, et al.Respir Med 2006 ** Ebeo CT, et al. Respir Med 2002 & Joris JL et al.Chest 1997 *** Huerta S, et al J Gastrointest Surg 2002
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*** *Hallowell PT, et al.American Journal of Surgery 2007 **Chung SA, et al.Anesthesiology 2008 *** Marshall NS et al.Sleep 2008.
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 Benumof JL Journal of Clinical Anesthesia, 2001
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 Chung F. Anesthesiology 2008 18
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. Chung F, Anesthesiology 2008
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. Anesthesiology 2006. A referral for PSG study should be individualized.
POTENTIALLY LIFE –THREATENING SLEEP APNEA IS UNRECOGNIZED WITHOUT AGGRESSIVE EVALUATION. Hallowell P.American J of Surgery 2007 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. Mandatory testing with Polysomnography Hallowell P.American J of Surgery, 2007
CPAP or BiPAP DURATION EFFECT STUDY 2 weeks correct abnormal ventilatory drive in obese hypercapneic patients Cartagena R. Anesthesiology clinics of North America 2005 3 weeks improves left ventricular ejection function in patients with CHF Tkacova et al.Circulation 1998. 4 weeks reduce HR, BP & 35% increase in EF in patients with CHF. Golbin JM,et al.Proceedings of the American Thoracic Society.2008 4- 6 weeks reduce tongue volume & increase pharyngeal space Ryan CT, et al.American Review of Respiratory Disease.1991 8 weeks improved morning hypertension Dorkova Z,et al.Chest 2008. 3-6 months reduced pulmonary hypertension Golbin JM,et al.Proceedings of the American Thoracic Society.2008 23
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. Bluman LG, Chest 1998
CARDIAC EVALUATION Cardiac abnormalities associated with morbid obesity include: * - Systemic hypertension. - Ischemic heart disease - cardiac hypertrophy. - Cardiac arrhythmias - diastolic dysfunction - Deep vein thrombosis. - Frank systolic dysfunction with cardiomyopathy.** - Pulmonary hypertension*** - Pulmonary embolism - Congestive heart failure. - Poor exercise capacity - Increased incidence of sudden and unexplained death**** *Poirier et al.Circulation 2009, **Thakur V,et al. Am J Med Sci 2001. ***Alpert MA. Am J Med Sci 2001. ****Drenick EJ.Am J Sur 1988.
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 O’ Neil T & Joanna A,Best Practice & Research Clinical Anesthesiology 2010
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 Lee TH, et al, Circulation.1999 SCORERISK 00.4% 10.9% 26.6% 311%
Cardiovascular evaluation and management of severely obese patients Paul 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. O’ Neil T & Joanna A,Best Practice & Research Clinical Anesthesiology 2010
CARDIORESPIRATORY FITNESS AND SHORT TERM COMPLICATIONS AFTER BARIATRIC SURGERY 31 McCullough PA,et al.Chest 2006
AIRWAY ASSESSMENT OBESE= PREDICTABLE DIFFICULT INTUBATION OSA SHORT + FAT NECK Airway claims intubation = 37% obesity Extubation 67% - 28% OSA. Peterson GN et al. Anesthesiology 2005
Obstructive sleep apnea is not a risk factor for difficult intubation in 180 morbidly obese patients Risk factors : Mallampati Score > 3 male gender Neligan PJ, et al.Anesthesia& Analgesia 2009 AIRWAY ASSESSMENT
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 ASA 2013 Schumann R.Best Practice & Research Clinical Anaesthesiology,2011
Reverse Trendelenburg = proclive Courtesy from Pr Paolo PELOSI
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) Golden SH, et al.Diabetes Care 1999. Van Den Berghe, et al.N Eng J Med,2001. Dronge AS, et al.Arch Surg.2005.
Outcomes of preoperative weight loss in high –risk patients undergoing gastric bypass surgery. > 10 % EXCESS BODY WEIGHT LOSS (N=425) 5%-10% EXCESS BODY WEIGHT LOSS (N=169) 0-5% EXCESS BODY WEIGHT LOSS (N= 137) 0-5% EXCESS BODY WEIGHT GAIN (N=86) > 5% EXCESS BODY WEIGHT GAIN (N=67) Still CD et al, Arch Surg 2007
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. DeMaria EJ, Surg Obes Relat Dis 2007 SCORE RISK MORTALITY 0-1 LOW 0.31% 2-3 INTERMEDIATE 1.9% 4-5 HIGH 7.56%