Comparison of cardiovascular function and quality of recovery in isoflurane-anaesthetised horses administered a constant rate infusion of lidocaine or lidocaine and medetomidine during elective surgery.
Authors: Valverde A, Rickey E, Sinclair M, Rioja E, Pedernera J, Hathway A, Cruz A
Journal: Equine veterinary journal
Summary
# Editorial Summary This investigation compared two intraoperative infusion protocols in horses undergoing arthroscopy under isoflurane anaesthesia: lidocaine alone versus lidocaine combined with medetomidine, evaluating both cardiovascular stability during surgery and recovery quality in 12 horses. The lidocaine-medetomidine combination was administered as a constant rate infusion for the duration of surgery (with lidocaine discontinued 30 minutes pre-closure), whilst the lidocaine-only group received identical lidocaine dosing but without medetomidine. Horses receiving the combined protocol demonstrated significantly improved recovery quality—characterised by better muscular strength and improved attitude during emergence—despite longer overall recovery times, whilst maintaining higher arterial blood pressure than the lidocaine-only group; crucially, cardiac output, blood gases, electrolytes and acid-base balance remained unaffected between groups. For practitioners managing equine surgical anaesthesia, these findings suggest that medetomidine addition to intraoperative lidocaine infusions offers meaningful benefits to recovery without compromising cardiovascular safety, making it a rational adjunct for procedures where smoother, more controlled emergence is clinically advantageous.
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Practical Takeaways
- •Adding medetomidine to intraoperative lidocaine infusions can safely improve recovery quality in horses under isoflurane anaesthesia for arthroscopy, without compromising cardiovascular stability
- •The combination supports better post-operative strength and attitude during recovery, potentially reducing complications and stress during the critical recovery period
- •Practitioners can confidently use lidocaine-medetomidine combinations during routine equine surgery, as this regimen maintains adequate arterial blood pressure and blood gas parameters
Key Findings
- •Lidocaine combined with medetomidine produced longer recoveries of better quality with improved strength and attitude compared to lidocaine alone
- •Arterial blood pressure was significantly higher in the lidocaine-medetomidine group, with this effect associated with medetomidine administration
- •No significant differences in cardiac output, arterial blood gases, electrolytes, or acid-base status were detected between the two treatment groups
- •The combination of lidocaine and medetomidine did not adversely affect cardiovascular function despite initial hypothesis predicting depression