Factors associated with survival of horses following relaparotomy.

Abstract

REASONS FOR PERFORMING STUDY: Relaparotomy may be required to investigate and manage complications that occur following surgical management of colic. OBJECTIVES: To report factors associated with survival following relaparotomy. STUDY DESIGN: Retrospective cohort study. METHODS: Records of horses that had undergone exploratory laparotomy for treatment of colic over a 10-year period (2002-2012) and had undergone relaparotomy <8 weeks following the initial surgery were reviewed. Descriptive data were generated and association with survival time was modelled using Cox proportional hazards models. RESULTS: Relaparotomy was performed in 96 horses at <8 weeks following initial surgery at a median of 4 days. This represented 6.3% of horses that underwent laparotomy during the study period (n = 1531). Relaparotomy was most frequently undertaken based on signs of persistent post-operative colic (76%; n = 73). Short-term survival for horses undergoing relaparotomy due to persistent colic was 53%, incisional dehiscence 50%, post-operative reflux 37%, haemoperitoneum 17% and septic peritonitis 0%. Median survival was 6 days for all horses undergoing relaparotomy and 778 days for those that recovered following anaesthesia. Nonsurvival was associated with increased packed cell volume at 24 h following initial laparotomy (hazard ratio [HR] 1.06, 95% confidence interval [CI] 1.04-1.10, P = 0.009), peritonitis as a reason for undertaking relaparotomy (HR 4.41, 95% CI 1.43-13.6, P = 0.01) and adhesions found at relaparotomy (HR 1.77, 95% CI 1.03-3.04, P = 0.04). Increased likelihood of survival was associated with colic signs being the reason for performing relaparotomy (HR 0.48, 95% CI 0.26-0.88, P = 0.02) and small intestinal distension found at relaparotomy (HR 0.53, 95% CI 0.29-0.96, P = 0.04). CONCLUSIONS: This study has provided information about survival rates and risk factors for survival in horses undergoing relaparotomy that can assist clinicians and owners when determining whether to perform relaparotomy and in predicting the likely surgical outcome.