Epsilon Archive for Student Projects

Abstract

Post-operative colic (POC) is a well-recognised complication in horses undergoing abdominal
surgery but there are few studies describing the prevalence and incidence of colic in horses after
non-abdominal surgery. Recently, the benefits of fasting horses pre-operatively have been
questioned. A future randomised prospective study is planned to investigate the beneficial or
negative effects of fasting horses prior to surgery. This retrospective pilot study was performed to
evaluate the incidence of post-operative colic after non- abdominal elective surgery, with the current
feeding regimen at SLU. Is there a problem that needs further investigation? Are specific procedures
associated with increased risk of POC? Can we identify any common risk factors that should be
included and separately studied in a prospective larger case-controlled study? Can we identify
possible risk factors in the management pre- and post-surgery that can be applied and changed to
decrease the risk of colic post-surgery?
We performed a retrospective study including elective non-abdominal procedures performed at SLU
between October 2021 and October 2022. The inclusion criteria were: all adult horses >1 year of
age, monitored in the hospital for a minimum of 24h following anesthesia, starved before the surgery
according to the pre-surgery feeding regimen at SLU, and not known to have a medical history of
colic within 6 months before surgery. In addition, we briefly investigated the incidence of post�operative colic following surgical procedures performed under standing sedation and when two
procedures were performed in close succession. Data was analysed using descriptive statistics,
hypothetical association tests and binary logistic regression analysis.
297 horses were included in the main study. We found an incidence of POC after non-abdominal
surgery of 13.5% (40/297) within 3 days post general anesthesia. The incidence of POC within 7
days post general anesthesia was 14.5% ((43/297). These results are markedly higher compared to
the previous described incidence of 2.5% (Bailey et al.2016) to 10.5% (Jago et al.2015). The
incidence of colic following standing surgery during CRI-sedation was 14.5% (10/69) within 3 days
post-operative. The incidence of colic following two separate anesthesia events performed close to
each other was 10.7% (3/28) within 3 days post the second surgical event.
The results indicate that pre- and especially post-operative management of the horse may alter the
risk of POC. We found that hand-walked exercise during hospitalization decreased the odds of
development of POC within our study population, an event to our knowledge not described before.
Our result also indicates that systemically administration of morphine given either intravenously or
intramuscularly during anesthesia may increase the risk to develop of POC. As previous reported by
Ekstrand et al. (2022), atropine treatment was associated with higher risk of colic. Higher age was
found associated with higher risk to develop POC. Comparing orthopaedical and non-orthopaedical
procedures, no association was found between procedure and increased risk for POC within our
study population. Neither did we find any association with breed type nor positioning during surgery
nor lidocaine constant rate infusion during anesthesia. We conclude that a larger prospective study
under controlled conditions needs to be performed, to further investigate if it is possible to decrease
the risk of POC following the finding of an uncommon high incidence. The result of literature review
in combination with the results from our pilot study indicates that different pre- and post-operative
feeding regimens should be included and evaluated.