Alfaxalone

To compare the sedative effects of intranasal (IN) alfaxalone to IM alfaxalone with or without IM midazolam in cockatiels (Nymphicus hollandicus).

A prospective, blinded, crossover study was performed on 8 healthy male cockatiels from February through April 2021. Birds randomly received 4 treatments with at least a 1-week washout period: alfaxalone at 15 mg/kg, IN (IN-A); alfaxalone at 15 mg/kg, IM, with (IM-AM) or without (IM-A) midazolam at 3 mg/kg, IM; and midazolam at 3 mg/kg, IM (IM-M). Time to recumbency and heart and respiratory rates were recorded. Ten minutes following administration, birds were restrained for sham 2-view radiographs and venipuncture. Following venipuncture, flumazenil at 0.1 mg/kg, IM, was administered (IM-AM and IM-M). Time to standing was recorded. Data were analyzed using a linear mixed model, a mixed effects γ-regression model, and Cochran Q, Friedman, and Wilcoxon signed-rank tests.

No sedative effects were observed in IN-A. Recumbency was achieved in 0/8, 5/8, 8/8, and 0/8 birds in IN-A, IM-A, IM-AM, and IM-M, respectively. Respiratory and heart rates remained within acceptable limits in all birds. Sham radiographs were acquired in 0/8, 1/8, 6/8, and 0/8 birds in IN-A, IM-A, IM-AM, and IM-M, respectively. Venipuncture was successful in all birds with median lactate concentrations of 4.9, 2.4, 1.0, and 1.8 mmol/L in IN-A, IM-A, IM-AM, and IM-M, respectively. Median (range) time to standing after handling in IM-A and IM-AM was 8.8 (0 to 15.0) and 14.5 (0.6 to 15.5) min, respectively.

Intranasal alfaxalone at 15 mg/kg did not produce sedation.

Intramuscular alfaxalone at 15 mg/kg with midazolam at 3 mg/kg produced sedation in cockatiels.

General anesthesia is a crucial tool in health care and clinical practice involving wildlife, including penguins. A balanced general anesthetic technique that combines multiple drugs is beneficial for achieving sufficient anesthesia while minimizing the side effects of individual agents. However, only a few studies have explored the use of multimodal anesthesia in penguins. This study examined the effects of midazolam (benzodiazepine) and butorphanol (mixed j-opioid agonist and weak l-opioid antagonist) as preanesthetic agents in gentoo penguins (Pygoscelis papua). Midazolam and butorphanol were administered intramuscularly at 0.25 mg/kg each, followed by anesthesia induction and maintenance with alfaxalone administered intravenously. Sedation level, required alfaxalone dose, recovery time, heart rate, and noninvasive blood pressure were evaluated during anesthesia. Sedation intensity increased over time after premedication. When midazolam and butorphanol were used as preanesthetics, the required alfaxalone dose for induction was 4.8 ± 0.8 mg/kg, and the mean infusion rate of alfaxalone required to maintain anesthesia was 0.12 ± 0.05 mg/kg per minute. Recovery from anesthesia took 3 (1-7) (median [interquartile range]) min for extubation and 20 ± 12 (mean ± SD) min for complete recovery. Heart rates were maintained within the normal physiological range, and noninvasive blood pressure remained stable. Compared with previous investigations on anesthesia induction and maintenance using alfaxalone alone, the intramuscular administration of 0.25 mg/kg midazolam and 0.25 mg/kg butorphanol reduced the alfaxalone dose requirement for anesthesia induction and maintenance, thereby shortening recovery times.