ABSTRACT
With refinement of the laparoscopic approach to bariatric surgery, there has been a recent surge in the number of bariatric operations being performed in the United States. The increase in the public demand for bariatric surgery has sparked an interest in many surgeons to incorporate bariatric surgery into their practice. Physiologically, laparoscopic bariatric surgery is different from an open bariatric surgery because of the intraoperative use of carbon dioxide gas (CO2) during pneumoperitoneum. Carbon dioxide pneumoperitoneum has been used clinically since the introduction of laparoscopic cholecystectomy in the late 1980s. The two main physiologic effects of pneumoperitoneum are systemic absorption of CO2, and hemodynamic and physiologic alterations from the increased intra-abdominal pressure. Carbon dioxide is easily absorbed across the peritoneal surface into the systemic circulation and can lead to hypercarbia. Without ventilatory changes, hypercarbia can lead to eventual systemic acidosis. The increased intra-abdominal pressure at 15 mmHg during pneumoperitoneumhas been shown to result in hemodynamic alteration including changes in femoral venous flow and renal, hepatic, and cardiorespiratory function (1-4). Morbidly obese patients often have many comorbid conditions that can predispose them to develop intraoperative complications associated with the use of pneumoperitoneum. Laparoscopic bariatric surgery, such as laparoscopic gastric bypass (GBP), is a complex operation and is often associated with a longer operative time than other commonly performed laparoscopic procedures. A longer operative time translates to longer exposure of these patients to the adverse physiologic effects of pneumoperitoneum. This chapter reviews our current understanding of the effects of pneumoperitoneum on CO2 absorption and excretion, femoral venous flow, and hepatic, renal, and cardiorespiratory function.
