Impact of intraoperative hypocapnia on postoperative complications in laparoscopic surgery for colorectal cancer

Purpose In laparoscopic surgery (LS) for colorectal cancer (CRC), the relationship between intraoperative end-tidal carbon dioxide concentration (EtCO 2 ) and surgery-related complications remains unexplored. This study assessed the impact of intraoperative EtCO 2 on postoperative complications in LS for CRC. Methods In total, 909 patients who underwent LS for CRC were enrolled. Hypocapnia and hypercapnia were defined as EtCO 2 40 mmHg, respectively, and the relationships between hypocapnia or hypercapnia duration and postoperative complications were analyzed. Results The median (range) durations of hypocapnia and hypercapnia were 2.0 (0–8.3) h and 0.3 (0–5.8) h, respectively. Complications were observed in 208 cases (23.0%), which included 37 (4.1%) instances of anastomotic leakage and 86 (9.5%) of superficial surgical site infection (SSI). While the hypercapnia duration was not associated with the short-term outcomes, prolonged hypocapnia was significantly correlated with complications ( p = 0.02), specifically superficial SSI ( p = 0.005). Multivariate analyses adjusted for confounding factors confirmed that hypocapnia prolongation was an independent risk factor for postoperative superficial SSI [OR 1.19; 95% confidence interval (Cl) 1.03–1.36, p = 0.01]. Conclusion Intraoperative hypocapnia may be a risk factor for postoperative complications, in particular superficial SSI, in LS for CRC.