Abstract: This study aimed to investigate the effects of administration intramuscularly of alfaxalone with or without dexmedetomidine, on the sedative effect and echocardiographic measurement in healthy cats. Baseline values of echocardiography and physiological indicators were determined before the experiment. Eight cats were intramuscularly injected with alfaxalone (5 mg·kg^-1, ALF), dexmedetomidine (5 μg·kg^-1 DEX) or both (DEX+ALF). The washout period was 2 weeks. Physiological indicators were measured immediately after anesthesia 0 (T0), 5 (T5), 10 (T10), 15 (T15), 20 (T20), 25 (T25) and 30 (T30) mins after the sedation effect was achieved. Echocardiography was performed at T15. After T30, the DEX and DEX+ALF groups were intramuscularly injected with atipamezole (25 μg·kg^-1). Times for cats to head-lift (LH), sternal recumbency (SRr), and standing position (ST) were recorded. The recovery time of DEX+ALF was shorter. Compared with the baseline value, alfaxalone decreased the respiratory rate and increased the heart rate of the cats, but did not significantly affect the echocardiographic results. The use of dexmedetomidine significantly reduced respiratory rate and heart rate, depressed the cardiovascular system, and affected the results of echocardiography significantly. The results of the DEX+ALF group were similar to the DEX group. All 3 kinds anesthesia methods could achieve sedative effect. Alfaxalone alone did not significantly affect echocardiographic parameters, but dexmedetomidine strongly depressed cardiovascular function even combined with alfaxalone it was not suitable for anesthesia before echocardiography.

Key words: cat, anesthesia, alfaxalone, dexmedetomidine, echocardiography