Peri-anaesthetic complications in an equine referral hospital: Risk factors for post anaesthetic colic

Reasons for performing studyPeri-anaesthetic complications are relatively common in equine patients and further investigations are warranted to identify manageable risk factors. ObjectivesTo report morbidity and mortality rates and identify associated risk factors for horses undergoing general anaesthesia, within a predominantly racing Thoroughbred (TB) population. Study designSingle centre retrospective observational study. MethodsAnaesthetic and case records of all horses 12months old undergoing general anaesthesia at Newmarket Equine Hospital between August 2010 and April 2012 were analysed, excluding emergency abdominal/dystocia procedures or traumatology cases with cardiovascular compromise. Mortality and morbidity rates were calculated and described. Uni- and multivariable analyses were used to investigate the relationship between the principal complication, post anaesthetic colic (PAC) and risk factors. ResultsA total of 1067 anaesthetic records of 1021 horses were included in the study; of these, 702 horses (65.8%) were TB, 169 (15.8%) developed a complication within 7days of general anaesthesia and 10 (0.94%) died as a result. The most prevalent morbidity was PAC, 111 horses (10.5%) developed colic within 7days of general anaesthesia. Thoroughbred horses (odds ratio [OR] 2.93, 95% confidence interval [CI] 1.73-4.96) and horses receiving sodium benzylpenicillin (NaBP) (OR 2.77, 95% CI 1.69-4.50) were at increased risk of PAC. ConclusionsThoroughbred racehorses were identified as at increased risk of PAC in this study and might benefit from more critical evaluation of post anaesthetic gastrointestinal function. An alternative to the administration of NaBP for prophylactic antimicrobial therapy needs to be further investigated if its role in PAC is confirmed by other studies.