Untoward cardiac changes during CO2 insufflation in laparoscopic cholecystectomies in low-risk patients

In the past decade, laparoscopic cholecystectomy has become the gold standard treatment for gallbladder disease. A debate has arisen about using CO2 to distend the abdomen because of negative effects on venous return to the heart and declining cardiac output. Some authors have supported the use of pulmonary artery catheters for intraoperative monitoring while others have recommended gasless techniques to avoid these negative effects for high-risk patients. In this study, four cases of bradycardia and/or asystole during CO2 pneumoinsufflation at the beginning of planned, elective laparoscopic cholecystectomies are described. These patients were ASA category II, without history of cardiac disease. To determine the frequency and any underlying common denominators, we analyzed these laparoscopic cholecystectomies. Each patient experienced bradycardia shortly after the start of the laparoscopic cholecystectomy. None had known cardiac disease or symptoms. Two were on antihypertensive medications, and one had experienced an episode of unexplained bradycardia 6 years earlier. These cases occurred during 725 laparoscopic cholecystectomies (0.6% approximately). Using the senior author's conversion rate of 10% to open cholecystectomies, the entire group would be approximately 800, and the risk of bradycardia upon induction of CO2 is 4 per 800, or 0.5%. Although cardiovascular changes were noted during laparoscopic gynecologic surgery approximately 20 years ago, only in the last few years have cardiovascular changes been reported during laparoscopic cholecystectomies. This study reviews four cases of bradycardia during CO2 insufflation in patients that were considered to be low-risk. Surgeons should be prepared to encounter such cardiovascular changes even with low-risk patients.