Correlation of Intraoperative End-Tidal Carbon Dioxide Concentration on Postoperative Hospital Stay in Patients Undergoing Pylorus-Preserving Pancreaticoduodenectomy

BACKGROUND: Hypocapnia has been traditionally advocated during general anesthesia, even though it may induce deleterious physiological effects that result in unfavorable outcomes in patients. This study investigated the association between intraoperative end-tidal carbon dioxide (EtCO(2)) and length of hospital stay (LOS) in patients who underwent pylorus-preserving pancreaticoduodenectomy (PPPD). METHODS: The medical records of 759 patients from 2006 to 2015 were reviewed. The patients were divided into two groups based on the mean EtCO(2) value during general anesthesia: the hypocapnia group (< 35 mmHg) and the normocapnia group (≥ 35 mmHg). The primary outcome was LOS between the groups. Secondary outcomes included the length of intensive care unit (ICU) stay, postoperative 30-day, 1-year, and 2-year mortality, and perioperative factors associated with LOS. RESULTS: A total of 727 patients were finally analyzed. The median LOS of the hypocapnia group was significantly longer than that of the normocapnia group (22 days vs. 18 days, respectively; p < 0.001). Postoperative mortality did not differ between the groups. Cox regression analysis revealed that hypocapnia was an independent risk factor for longer LOS (hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.37–1.89; p < 0.001). Age and postoperative pancreatic fistula were also risk factors for a longer LOS. CONCLUSIONS: It was concluded that low levels of intraoperative EtCO(2) during general anesthesia were associated with an increased LOS for patients undergoing PPPD.