Intraoperative carbon dioxide management and outcomes

Abstract

Background and objective: Intraoperative hyperventilation to induce hypocapnia has historically been common practice and has physiological effects that may be detrimental. In contrast, hypercapnia has effects that may be beneficial. As these effects may influence postoperative recovery, we investigated the association between variations in intraoperative carbon dioxide and length of hospital stay in patients who had elective colon resections and hysterectomies.

Methods: Data were extracted from electronic records for elective colon resections and hysterectomies done from 2002 to 2008. Patients were divided into four groups based on surgical procedure and use of laparoscopic technique. Parameters extracted for analysis included mean end-tidal carbon dioxide (EtCO2) during the surgical procedure as well as others previously purported to affect postoperative outcomes. In-hospital length of stay (LOS) was determined from administrative records and was used as the independent outcome variable. For each group, Poisson regression analysis was performed to find factors that were independently associated with the outcome.

Results: A total of 3421 case records in our database met inclusion criteria. Median EtCO2 was 31 mmHg. Median LOS was 7 and 5 days for open and laparoscopic colon resections, and 3 and 2 days for open and laparoscopic hysterectomies, respectively. Regression analysis revealed a statistically significant independent association between higher EtCO2 and reduced LOS for colon resection and open hysterectomy.

Conclusion: There is a significant association between higher intraoperative EtCO2 and shorter LOS after colon resection and open hysterectomy. The common practice of inducing hypocapnia may be deleterious, and maintaining normocapnia or permitting hypercapnia may improve clinical outcomes.