Anaesthesia for bariatric surgery

As a disease of epidemic proportion, obesity is increasingly becoming a target for management by patients and their physicians. Its incidence is increasing. As a concept, ideal body weight (IBW) was conceived in life insurance studies after looking at the occurrence of obesity-related complications and morbidity, and determining maximum life expectancy.1 The ideal body weight is therefore the body weight at which the patient is at least risk for weight-associated morbidity. Normal body weight ranges between 10% above and below IBW. Body mass index (BMI) (Quatelet’s index) is a commonly used ratio of body weight in kilogram to squared height in metre. Patients with a BMI of more than 30 are considered obese, more than 35 with multiple medical co-morbidities, morbidly obese, and more than 50 as super obese. Obesityrelated diseases that patients are at risk for in these categories, particularly in the central android distribution, include hypertension, dyslipidaemia, ischaemic heart disease, glucose intolerance and diabetes mellitus. Other than these, the list of medical conditions associated with obesity is long. It includes respiratory (restrictive lung disease and obstructive sleep apnoea), cardiovascular (cardiomegaly, congestive heart failure, peripheral vascular disease, thromboembolism and pulmonary hypertension), endocrine (Cushing’s syndrome, hypothyroidism and vitamin deficiencies), gastrointestinal (hiatal, inguinal and ventral hernia, fatty liver/nonalcoholic steatohepatitis [NASA] and gallstones), musculoskeletal (osteoarthritis and low back pain), and malignant (breast, prostrate, cervical, uterine and colorectal) conditions. It is also associated with socio-economic and psychosocial impairment.