Protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in horses.
Authors: VanderBroek Ashley R, Engiles Julie B, Kästner Sabine B R, Kopp Veronika, Verhaar Nicole, Hopster Klaus
Journal: Equine veterinary journal
Summary
# Editorial Summary: Dexmedetomidine Protection Against Small Intestinal Ischaemia-Reperfusion Injury Strangulating small intestinal obstructions in horses carry substantially worse outcomes than non-strangulating cases because the combination of ischaemia and reperfusion damages the mucosal barrier, triggering life-threatening endotoxaemia. VanderBroek and colleagues conducted a randomised controlled trial to evaluate whether dexmedetomidine could mitigate this injury in 18 anaesthetised horses, inducing complete ischaemia in a 1-metre jejunal segment for 90 minutes and administering dexmedetomidine (bolus 3.5 µg/kg followed by infusion 7 µg/kg/h) either before ischaemia began (preconditioning) or once ischaemia was underway (post-conditioning). Jejunal biopsies assessed at baseline, end of ischaemia, 30 minutes post-reperfusion, and 24 hours post-reperfusion revealed that untreated control animals showed persistent epithelial injury and progressive villus denudation across all time points, whilst both dexmedetomidine groups maintained epithelial integrity comparable to baseline—particularly the preconditioning group, which showed no significant injury markers at any stage. Although preconditioning offers limited practical application in emergency colic cases where strangulation is rarely anticipated, post-conditioning dexmedetomidine administration during the critical reperfusion phase presents a genuine therapeutic opportunity for veterinarians managing acute small intestinal lesions intraoperatively, potentially improving survival and long-term intestinal function in these high-mortality cases.
Read the full abstract on PubMed
Practical Takeaways
- •Dexmedetomidine may reduce intestinal damage during ischaemic episodes if administered before or early during ischaemia, potentially improving outcomes in surgical colic cases
- •While preconditioning is impractical for emergency strangulating obstructions, post-conditioning with dexmedetomidine during reperfusion could be incorporated into immediate post-operative protocols
- •This experimental evidence supports investigating dexmedetomidine as a protective agent in colic surgery to reduce reperfusion injury and improve healing
Key Findings
- •Dexmedetomidine preconditioning prevented epithelial injury and villus surface area denudation in ischaemia-reperfusion-injured jejunum, with no difference from baseline at any time point
- •Post-conditioning with dexmedetomidine reduced epithelial injury scores and villus denudation compared to control group at ischaemia and both reperfusion timepoints
- •Control group showed significantly higher epithelial injury scores and percentage of villus surface area denudation at all timepoints compared to baseline
- •Preconditioning has limited clinical application for naturally occurring strangulating lesions due to the sudden onset of colic