Effects of hypercapnia on postoperative nausea and vomiting after laparoscopic surgery: a double-blind randomized controlled study.

Background: Laparoscopic surgery is associated with a high incidence of postoperative nausea and vomiting (PONV). The use of CO pneumoperitoneum has been proposed as a potential cause of high PONV incidence. However, intraoperative hypercarbia may be related to enhanced perfusion to the main effector sites for PONV, including the brain and gastrointestinal tract. In this study, we investigated whether an increase in intraoperative CO partial pressure in arterial blood (PaCO) reduces the incidence of PONV.

Methods: This study enrolled 400 female patients aged 20-60 years who were undergoing laparoscopic gynecologic surgery. The patients were allocated randomly to one of three groups with the following intraoperative PaCO levels: 36-40 mmHg (Group 1), 41-45 mmHg (Group 2), or 46-50 mmHg (Group 3). The anesthetic regimen used a standardized total intravenous anesthesia consisting of propofol and remifentanil for all patients. The arterial blood gas analysis was performed to identify the difference in CO partial pressure between arterial blood and end-tidal gas. The PONV incidence was evaluated for the periods of 0-2, 2-6, and 6-24 h after anesthesia. The incidence and severity of PONV and the administration of rescue antiemetics were recorded.

Results: The three groups were comparable for the patient, anesthesia, and surgical characteristics. The average PaCO level during surgery was 38-39, 43-44, and 47-48 mmHg in Groups 1, 2, and 3, respectively. The incidence and severity of PONV and use of rescue antiemetics were not significantly different among the groups. The overall incidence of nausea during the first 24-h postoperative period was 54, 48, and 50% in Groups 1, 2, and 3, respectively (P = 0.593).

Conclusion: Our data suggest that mild to moderate intraoperative hypercapnia did not decrease the incidence and severity of PONV or the requirement for rescue antiemetics after gynecologic laparoscopic surgery.