Duration of disease influences survival to discharge of Thoroughbred mares with surgically treated large colon volvulus.

Reasons for Performing Study: Large colon volvulus results in strangulating obstruction requiring surgical treatment. Duration of this disease prior to surgical treatment is likely to influence survival directly.
Objectives: The primary objective of this study was to evaluate the influence of duration of large colon volvulus on patient survival to discharge. Relationships between other factors and survival following large colon volvulus were also examined.
Study Design: Retrospective case analysis.
Methods: Medical records of Thoroughbred mares aged ≥2 years undergoing surgical treatment for large colon volvulus between 1 March 1986 and 28 February 2011 were reviewed. Multivariable logistic regression was used to identify influence of duration and other factors on survival to discharge.
Results: Within the study period, 1039 surgeries were performed to correct large colon volvulus in 896 Thoroughbred mares. Median duration of colic signs prior to admission was 2 h (interquartile range [IQR] 1-4 h). Median time from admission to anaesthetic induction was 25 min (IQR 15-45 min). Median surgical time was 70 min (IQR 55-85 min). Primary surgical treatment was simple correction of the large colon volvulus followed by replacement of the colon. The overall survival to discharge was 88%. The final model identified risk factors significantly associated with survival and included colic duration prior to admission, packed cell volume at admission, surgery length, duration of hypotension while under anaesthesia, heart rate 48 h post operatively, post operative manure consistency and days hospitalised.
Conclusions: Duration of colic prior to admission was statistically associated with patient survival to discharge. Other factors significantly associated with survival in mares with large colon volvulus were related to disease severity and degree of colonic compromise. Mares with large colon volvulus have a good prognosis for recovery with early referral and prompt surgical treatment.
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