Evaluation of a stent dressing and abdominal bandage on surgical site infection following emergency equine laparotomy: A randomised controlled trial.

Background: Surgical site infection (SSI) is a frequent complication following emergency equine laparotomy, negatively impacting equine welfare, increasing treatment costs and presenting a hospital biosecurity risk.

Objectives: To determine if a sutured-on stent dressing for incisional protection during anaesthetic recovery reduced SSI following emergency laparotomy.

Study design: Randomised controlled trial.

Methods: Eligible horses were randomised to a sutured-on stent (intervention) or textile dressing (control) as the primary component of a 3-layer abdominal bandage placed for anaesthetic recovery. Horses were followed up to 90 days postoperatively. Data were analysed according to intention-to-treat principles. Time to SSI (primary outcome) for each group was analysed using a Cox proportional hazard model. Secondary outcomes (SSI and pyrexia during hospitalisation, days hospitalisation and incisional hernia formation at 90 days) were analysed using Chi-squared tests and a univariable logistic regression model (categorical data) or by comparing means between groups (continuous data).

Results: Of 352 eligible horses enrolled (167 intervention group, 185 control group), SSI developed in 101 (28.7%) at a mean of 9.7 days (SD 4.6 days). Rate of SSI was not significantly different between groups unadjusted (hazard ratio [HR] 0.83, 95% CI 0.56-1.23, p = 0.4) or adjusted for variables significantly associated with rate of SSI (HR 0.88, 95% CI 0.59-1.30, p = 0.5). There were no significant differences in secondary outcomes between intervention and control groups.

Main limitations: Single-centre study evaluating incisional protection from a primary dressing under a secondary adhesive and tertiary fabric abdominal bandage for anaesthetic recovery.

Conclusions: Use of a sutured-on stent compared with a textile adhesive dressing as the primary layer of an abdominal bandage for anaesthetic recovery did not reduce the rate of SSI. Further RCT are warranted to investigate efficacy of other interventions on reduction of SSI following emergency laparotomy in horses.