Dr Hany FawziSenior Specialist-

Anesthesia DepartmentRashid Hospital & Trauma Center

7 March 2013

BARIATRIC SURGERYUSA bariatric surgeries /year:

16 200 (1992) 220 000 (2008).

344 000 worldwide (2008)

Schumann R ,Best practice & Research Clinical Anaesthesiology 2010

DEFINITIONSBODY MASS INDEX BMI ( Quetelet’s Index): WEIGHT(kg)/HEIGHT (m2)

BMISEVERE OBESITY 35-39.9MORBID OBESITY > 40SUPER OBESITY > 50

WEIGHT FEMALE MALEIDEAL 19.1-25.8 20.7-26.4MARGINAL OVERWEIGHT

25.9-27.2 26.5-27.8

OVERWEIGHT 27.3-32.3 27.9-31.3OBESE 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, 5Male : X = 50

More easy to rememberIBW (kg) = Height (cm) - 100 in MALE IBW (kg) = Height (cm) - 110 in FEMALE

OBESE PATIENT = RISKS

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%Benotti P.Surg Obes Relat Dis 2006

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

32 + 6 BMI 0.001 35 + 80.2% 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%

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.

PREOPERATIVE ASSESSMENT=

Multidisciplinary

Benotti.P, Gastroenterology & Endoscopy news 2007

Special Bariatric SurgeonAnesthesiologist

MedicalCardiologyPulmonaryDiabetologyEndoscopistPsychiatryDietitianPlastic 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.

Koening SM.Am J Med Sci 2001

RESPIRATORY SYSTEMDyspnea 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 EVALUATIONPreoperative pulmonary function tests are

indicated for patients with1- 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 2001Benotti P.Surg Obes Relat Dis 2006

PULMONARY EVALUATIONForced 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 QUESTIONNAIRESTOP 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 patientswith 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 PSGcost 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 STUDY2 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 EVALUATIONCardiac 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 EVALUATIONCardiac 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 surgery2 IHD.3 CHF. 4 Cerebrovascular disease.5 IDDM 6 Renal insufficiency.

IF YES = 1 POINT/ITEM

Lee TH, et al , Circulation .1999

SCORE RISK0 0.4%1 0.9%2 6.6%3 11%

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.

O ’ Neil T & Joanna A ,Best Practice & Research Clinical Anesthesiology 2010

CARDIORESPIRATORY FITNESS AND SHORT TERM COMPLICATIONS AFTER BARIATRIC SURGERY

31McCullough PA,et al.Chest 2006

AIRWAY ASSESSMENTOBESE= PREDICTABLE DIFFICULT

INTUBATIONOSASHORT + FAT NECK

Airway claimsintubation = 37% obesityExtubation 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 MANAGEMENTOptimal 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

VASCULAR ACCESS

ENDOCRINE FUNCTION15 -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 SYSTEMSObesity 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%

CLINICAL PATHWAY

CLINICAL PATHWAY

CLINICAL PATHWAY

HOME MESSAGESExponential increase in Bariatric surgery

worldwide.

Comorbidities affect outcome.

Pre-operative evaluation is Multidisplinary.

Anesthetic evaluation & preparation.

Clinical pathway.43