Surgical site infection after colorectal surgery according to the main anesthetic agent: a retrospective comparison between volatile anesthetics and propofol

BACKGROUND Anesthetic agents used for general anesthesia are emerging possible influential factors for surgical site infection (SSI). In this retrospective study, we evaluated the incidence of SSI after colorectal surgery according to the main anesthetic agents: volatile anesthetics vs. propofol. METHODS A total 1,934 adult patients, who underwent elective colorectal surgery under general anesthesia between January 2011 and December 2013, were surveyed to evaluate the incidence of SSI: 1,519 using volatile anesthetics and 415 using propofol for main anesthetic agents. Patient, surgery, and anesthesia-related factors were investigated from all patients. Propensity-score matching was performed to reduce the risk of confounding and produced 390 patients in each group. RESULTS Within the propensity-score matched groups, the incidence of SSI was higher in the volatile group compared with the propofol group (10 [2.6%] vs. 2 [0.5%], OR = 5.0 [95% CI = 1.1-2.8]). C-reactive protein was higher in the volatile group than in the propofol group (8.4 ± 5.6 vs. 7.1 ± 5.3 mg/dl, P = 0.001), and postoperative white blood cells count was higher in the volatile group than in the propofol group (9.2 ± 3.2 × 10(3)/µl vs. 8.6 ± 3.4 × 10(3)/µl, P = 0.041). CONCLUSIONS The results of this study suggest that intravenous anesthesia may have beneficial effects for reducing SSI in colorectal surgery compared to volatile anesthesia.