Continuous versus Intermittent Infusion of Prophylactic Cefoxitin After Colorectal Surgery: A Pilot Study

Abstract

To compare 30-day postoperative surgical site infections (SSIs) and rates of antibiotic discontinuation within 24 hours after surgery in patients receiving continuous-infusion versus intermittent-infusion cefoxitin for postoperative antibiotic prophylaxis. Retrospective, cohort-matched pilot study. Tertiary-care medical center. One hundred sixteen adults undergoing colorectal surgery between August 1, 2004, and February 28, 2007. Cefoxitin prophylaxis was administered as a continuous infusion in 58 patients and as an intermittent infusion in 58 patients (controls). The controls received weight-based doses of cefoxitin (1 g if < or = 80 kg or 2 g if > 80 kg) every 8 hours for three doses, starting 3 hours after surgery and completed within 24 hours. The continuous-infusion group were given weight-based doses of cefoxitin (3 g if < or = 80 kg, 6 g if > 80 kg), started immediately after surgery and infused over 20 hours. Patients and controls were matched according to colorectal procedure and risk index category. They were stratified by medium risk (50 patients) and low risk (66 patients) for the end point of 30-day postoperative SSI. For the 25 medium-risk patients who received the continuous infusion, a 50% relative reduction in the 30-day postoperative SSI rate was observed with continuous versus intermittent infusion (4% vs 8%, p=0.55). For the 66 low-risk patients, 30-day postoperative SSI rates were equal (3%) with both intermittent and continuous infusions. Risk stratification was not performed for the proportion of patients who discontinued antibiotic prophylaxis within 24 hours after surgery. All patients receiving the continuous infusion met this end point compared with 47 (83.9%) of the 56 controls (p=0.0015) included in the analysis. Compared with intermittent infusion, continuous infusion of cefoxitin for postoperative prophylaxis resulted in a nonsignificant reduction in 30-day postoperative SSI rates in medium-risk patients undergoing colorectal surgery. Continuous infusion also resulted in reliable discontinuation of postoperative prophylaxis within 24 hours.