Alfaxalone priming lowers anesthesia dose and affects heart

Abstract

OBJECTIVE: To investigate the effects of a priming dose of alfaxalone on the total anesthetic induction dose for and cardiorespiratory function of sedated healthy cats. ANIMALS: 8 healthy adult cats. PROCEDURES: For this crossover study, cats were sedated with dexmedetomidine and methadone administered IM. Cats next received a priming induction dose of alfaxalone (0.25 mg/kg, IV) or saline (0.9% NaCl) solution (0.025 mL/kg, IV) over 60 seconds and then an induction dose of alfaxalone (0.5 mg/kg/min, IV) until orotracheal intubation was achieved. Cardiorespiratory variables were recorded at baseline (immediately prior to priming agent administration), immediately after priming agent administration, after orotracheal intubation, and every 2 minutes until extubation. The total induction dose of alfaxalone was compared between the 2 priming agents. RESULTS: Mean &#xb1; SD total anesthetic induction dose of alfaxalone was significantly lower when cats received a priming dose of alfaxalone (0.98 &#xb1; 0.28 mg/kg), compared with when cats received a priming dose of saline solution (1.41 &#xb1; 0.17 mg/kg). Mean arterial blood pressure was significantly higher when alfaxalone was used as the priming dose. No cats became apneic or had a hemoglobin oxygen saturation of < 90%. Expired volume per minute was not significantly different between the 2 priming agents. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of a priming dose of alfaxalone to healthy sedated cats reduced the total dose of alfaxalone needed to achieve orotracheal intubation, maintained mean arterial blood pressure, and did not adversely impact the measured respiratory variables.