Bariatric Anaesthesia

Obesity is a complex multi-system disorder, which is increasingly recognized as one of the greatest challenges faced by health care systems throughout the world. Obesity is classified on the basis of both the BMI and the fat distribution. Surgical bariatric procedures can achieve up to 50% weight loss and this is sustained for a longer period of time. The procedures, although not without risk, are relatively safe with low morbidity and mortality rates. A key marker for increased risk of perioperative complications is central obesity. The presence of obstructive sleep apnoea is an independent marker of risk that leads to the doubling of postoperative respiratory and cardiac complications. Obese patients will have a markedly different volume of distribution of drugs as a result of the adipose tissue. To compensate for these changes drug dosing in obese patients is based on a combination of adjusted body weight, total body weight, ideal body weight and lean body mass. Adequate time and preparation is essential to provide safe conditions to anaesthetise obese patients. There are specific considerations for the intra-operative anaesthetic management of obese individuals, which need to be adhered to for the safe conduct and reversal of anaesthesia. Most patients presenting for bariatric surgery can be discharged to a ward environment. However, some patients carry an increased risk and as such may be required to be cared for in a high dependency or an intensive care unit. In addition, a number of patients may require specific measures for safe hospital discharge.

Keywords: Anaesthesia, Anaesthetic management, Analgesia, Bariatric surgery, Monitoring, Obesity hypoventilation syndrome, Obstructive sleep apnoea, Postoperative care, Respiratory function, Risk stratification scores.