Polyethylene glycol versus sodium phosphate mechanical bowel preparation in elective colorectal surgery.

The type of mechanical bowel preparation (MBP) used before elective colorectal surgery remains controversial. This post hoc analysis of a prospective randomized controlled antibiotic prophylaxis trial (ertapenem vs. cefotetan) evaluated the effect of polyethylene glycol (PEG) and sodium phosphate (SP) MBPs on the rates of postoperative surgical site infections (SSI). Good to excellent MBPs were observed in 281 of 303 (93%) evaluable patients for the PEG and 336 of 367 (92%) for the SP types. A higher rate of SSI was observed in the PEG (34%) than SP (24%) group (difference, 10%; 95% confidence interval, 3.4-17.2). The MBP type was a significant risk factor for SSI, with SP favored over PEG (odds ratio, .6; 95% confidence interval, .43-.85) in univariate analysis; multivariate analysis favored SP, but was not significant (odds ratio, .69; 95% confidence interval, .46-1.02). SSI was lowest with SP and ertapenem (19%) and highest with PEG and cefotetan (44%). SP, coupled with ertapenem antibiotic prophylaxis, may improve outcomes and reduce SSIs in patients undergoing elective colorectal surgery when compared with PEG coupled with cefotetan antibiotic prophylaxis.