Is mechanical bowel preparation necessary to reduce surgical site infection following colon surgery? Protocol for a multicentre Canadian randomized controlled trial.

Abstract

There is significant practice variation with respect to the use of bowel preparation to reduce surgical site infection (SSI) following colon surgery. Although intravenous antibiotics + mechanical bowel preparation + oral antibiotics (IVA + MBP + OA) has been shown to be superior to IVA + MBP and IVA, there are insufficient high-quality data from randomized controlled trails (RCTs) that directly compare these options. This is an important question, because if IVA + OA has similar effectiveness to IVA + MBP + OA, mechanical bowel preparation can be safely omitted, and the associated side effects avoided. The aim of this work is to compare rates of SSI following IVA + OA + MBP (MBP) versus IVA + OA (OA) for elective colon surgery. This is a multicentre, parallel, two-arm, noninferiority RCT comparing IVA + OA + MBP versus IVA + OA. The primary outcome is the overall rate of SSI 30 days following surgery. Secondary outcomes are length of stay and 30-day emergency room visit and readmission rates. The planned sample size is 1062 subjects with four participating high-volume centres. Overall SSI rates 30 days following surgery between the treatment groups will be compared using a general linear model. Secondary outcomes will be analysed with linear regression for continuous outcomes, logistic regression for binary outcomes and modified Poisson regression for count data. It is expected that IVA + OA will work similarly to IVA + MBP + OA and that this work will provide definitive evidence showing that MBP is not necessary to reduce SSI. This is highly relevant to both patients and physicians as it will have the potential to significantly change practice and outcomes following colon surgery in Canada and beyond.