Retrospective evaluation of alfaxalone as an induction agent of inhalation anesthesia: 150 cases

This study was performed to evaluate the clinical efficacy of alfaxalone for induction of inhalation anesthesia in small animal practice. Patient data were collected according to anesthetic records (136 dogs and 14 cats) presented to the Veterinary Medical Teaching Hospital of Seoul National University for surgeries and diagnostic imaging from July 2013 to March 2014. Anesthetic results included signalment, American Society of Anesthesiologists (ASA) grade, premedicated drugs, procedures, induction quality, and recovery after anesthesia. One hundred fifty anesthetic events were classified according to the ASA grade. Three patients were ASA grade I, 52 patients grade II, 86 patients grade III, and 9 patients grade IV, respectively. The most common premedication was midazolam and hydromorphone combination (n = 59, 39.3%) follow by acepromazine and hydromorphone combination (n = 22, 14.7%). The majority of anesthesia procedures were diagnostic imaging (n = 33, 22.0%) and ophthalmic surgeries (n = 31, 20.7%), followed by soft tissue surgeries (n = 27, 18.0%), and orthopedic surgeries (n = 20, 13.3%). Intravenous alfaxalone provided smooth induction for inhalation anesthesia in almost cases, but transient apnea and twitching/paddling were observed after induction and during recovery, respectively. In addition, alfaxalone did not show pain response during intravenous administration. Alfaxalone showed smooth induction of inhalation anesthesia in dogs and cats with mild to severe systemic disease (ASA 2-4). Alfaxalone was considered as an acceptable induction agent for patients with higher risk in small animal practice.