Reasons for performing study: Lidocaine constant rate infusions (CRIs) are common as an intraoperative adjunct to general anaesthesia, but their influence on quality of recovery has not been thoroughly determined.
Objectives: To determine the effects of an intraoperative i.v. CRI of lidocaine on the quality of recovery from isoflurane or sevoflurane anaesthesia in horses undergoing various surgical procedures, using a modified recovery score system.
Hypothesis: The administration of intraoperative lidocaine CRI decreases the quality of recovery in horses.
Methods: Lidocaine (2 mg/kg bwt bolus followed by 50 μg/kg bwt/min) or saline was administered for the duration of surgery or until 30 mins before the end of surgery under isoflurane (n = 27) and sevoflurane (n = 27).
Results: Horses receiving lidocaine until the end of surgery had a significantly higher degree of ataxia and a tendency towards significance for a lower quality of recovery. There was no correlation between lidocaine plasma concentrations at recovery and the quality of recovery.
Conclusions: Intraoperative CRI of lidocaine affects the degree of ataxia and may decrease the quality of recovery.
Potential relevance: Discontinuing lidocaine CRI 30 mins before the end of surgery is recommended to reduce ataxia during the recovery period.