Acute toxicity of intravenous isoflurane in Beagles

Objective To investigate the acute toxicity of intravenous isoflurane in Beagles. Methods Six healthy adult Beagles of both sexes aged 6-8 months weighing 6-8 kg were used in this study. Isoflurane injeetio （120 mg/ml） in 30% lipid emulsion was injected intravenously. Femoral artery was cannulated for direct BP monitoring. ECG was continuously monitored. The maximal tolerance dose （MTD） and approximate lethal dose （ALD） were determined by up-and-down technique. The initial dose was 3.0 ml/kg. The close was decreased/ increased by 0.3 ml/kg if the previous animal died/survived. The survived dogs were observed for 2 weeks. Autopsy and histopathologieal examination were performed on all dead Beagles. Results The ALl） and MTD of intravenous isoflurane were 252 and 216 mg/kg. Autopsy and histopathological examination did not show any abnormality. Conclusion Cardiopuhnonary depression is the main manifestation of the acute toxicity of intravenous isoflurane in Beagles. Key words: Isoflurane ;  Acute toxicity tests ;  Maximum tolerated dose