Anesthetic Recovery Following a Midazolam-Containing Co-Induction Protocol in Horses Undergoing Total Intravenous...

Anesthetic recovery is a critical phase in horses under field conditions, and induction protocols may influence recovery quality during total intravenous anesthesia.

To compare two anesthetic induction protocols, one including midazolam and the other based solely on xylazine and ketamine, regarding anesthetic induction and recovery quality, total recovery time, and attempts to achieve standing in horses undergoing total intravenous anesthesia.

Twelve healthy male horses older than 2 years were randomly assigned to XC (xylazine 1 mg/kg and ketamine 2 mg/kg) or XCM (xylazine 0.5 mg/kg, ketamine 2 mg/kg, and midazolam 0.1 mg/kg). Anesthesia was maintained with continuous guaifenesin, ketamine, and xylazine infusion. Induction and recovery quality, total recovery time, and attempts to achieve standing were evaluated.

Induction quality scores were 3.5 (1-4) for XC and 3.5 (2-5) for XCM (P = 0.61). Total recovery time was 80.3 ± 15.5 and 80.2 ± 20.5 min, respectively (P = 0.98). Recovery quality was poorer with XCM on the descriptive scale [2.5 (2-4) vs. 1 (1-1); P = 0.003] and quantitative scale (40.3 ± 11.5 vs. 19.0 ± 3.2; P = 0.002). Attempts to achieve standing were 2 (1-4) with XCM and 1 (1-1) with XC (P = 0.03).

Under the conditions studied, XCM was associated with poorer recovery quality and more attempts to achieve standing than XC.