Recent Advancements in Anesthesia for Bariatric Surgeries

Abstract

SUMMARY T he dramatic rise in the incidence of obesity in many countries appears to be due to the complex interaction of a variety of factors including genetic, physiologic, environmental, psychological, social, economic and political. Given the numerous and significant deleterious health consequences associated with obesity, there is the urgent need for the development of highly effective interventions that aim to reverse these obesogenic drivers, including government policies as well as health education and promotion programs. Obesity is an exaggeration of normal adiposity and is a central player in the pathophysiology of diabetes mellitus, insulin resistance, dyslipidemia, hypertension, and atherosclerosis, largely due to its secretion of excessive adipokines. Obesity is a major contributor to the metabolic dysfunction involving lipids and glucose and; on a broader scale, it influences organ dysfunction of the cardiac, liver, intestinal, pulmonary, endocrine, and reproductive systems. The aim of bariatric surgery is to reduce the volume of the gastric cavity resulting in the development of satiety after the ingestion of a small volume of food. The strategy to this early satiety involves creating a small gastric pouch together with a limited gastric outlet. This is the goal of the restrictive type of bariatric surgery. The alternative is to perform malabsorptive procedures, which not only limits the size of the stomach by creating a small gastric pouch, but also involves shortening the length of the gut, thereby reducing the amount of food absorbed. A thorough understanding of the pathophysiologic changes, pharmacology of weight-loss drugs, and perioperative course will allow a high quality, safe surgical experience. The preoperative assessment of the patient is crucial in identifying and stratifying risk to ascertain the level of perioperative care required, and also each individual’s suitability for surgery. Patients should be assessed by a multidisciplinary team, which may include endocrinologists, dieticians, psychologists, specialist nurses, and experienced surgeons and anesthesiologists. Preoperative laboratory tests, Chest X-ray, Spirometry, ECG and echocardiography are essential. Further evaluation for cardiac function such as stress testing and coronary angiography are done when needed. Morbid obesity patients present many challenges during the intraoperative period. Major areas of concern include patient positioning on operating tables, monitoring, airway management, ventilation, drug weight-based dosing. Ramping position makes the intubation easier. Invasive arterial monitoring obtains an accurate blood pressure readings and central venous catheters are used in cases in which peripheral IV access cannot be obtained. Optimal ventilation includes the use of high tidal volumes, alveolar recruitment maneuvers, positive end-expiratory pressure, and high oxygen concentration. Drugs need to be adjusted due to changes in volume of distribution in obese patients. Heparin, 5,000 IU, is administered subcutaneously before surgery and compression stockings are routinely used for prophylaxis against DVT perioperatively.