Abstract / Summary
Abstract Background Postoperative nausea and vomiting is common after gynecological laparoscopic surgery despite the use of prophylactic antiemetic medication. This study investigated that whether a permissive hypercapnia ventilation strategy during surgery reduces the PONV. Methods In this prospective, randomized, controlled trial, 88 female patients aged 18–64 years undergoing gynecological laparoscopic surgery were randomly assigned to conventional normocapnic ventilation (control group, PaCO2 34–45 mmHg) or permissive hypercapnic ventilation (PHC group, PaCO2 45–55 mmHg). All patient received standardized general anesthesia. The primary outcome was the overall incidence of PONV within 24 h after surgery. Secondary outcomes include the incidence of nausea, retching and vomiting, rescue antiemetic use, perioperative hemodynamic variables, postoperative pain, and adverse events. The rSO2 before anesthesia, 10 min and 60 min after pneumoperitoneum, and at the end of surgery was also measured. Results Eighty-three patients were included in the final analysis, comprising 42 patients in the C group and 41 patients in the PHC group. The incidence of PONV within 24 h was significantly lower in the PHC group than in the control group (39.0% vs 71.4%, 95% CI = 1.56–9.78, P = 0.004). The overall episodes of nausea was lower within 24 h after surgery in the PHC group (41 vs 21, 95% CI = 0.31–0.89, P = 0.016), and the overall episodes of vomiting was lower within 24 h after surgery in the PHC group (19 vs 9, 95% CI = 0.24−1.00, P = 0.005). Rescue antiemetic use and postoperative pain scores were comparable between groups. Baseline rSO 2 did not differ between groups. However, rSO 2 was significantly higher in the PHC group than in the C group 60 min after pneumoperitoneum (66.9 vs 62.1, P < 0.001) and at the end of surgery (64.4 vs 61.0, P = 0.007). Conclusions In patients undergoing gynecological laparoscopic surgery, a permissive hypercapnia ventilation strategy targeting PaCO2 at 45–55 mmHg was associated with a lower incidence of PONV and higher intraoperative regional cerebral oxygen saturation. The concurrent improvement in cerebral oxygenation provides a potential physiological explanation for the observed reduction in PONV, although the underlying causal mechanisms remain uncertain. Trail registration The trial was retrospectively registered Chinese Clinical Trial Registry (ChiCTR2500096048, date of registration: 2025-01-16).