Effect of intravenous dose escalation with alfaxalone and propofol on occurrence of apnoea in the dog.

摘要

Spontaneous ventilation after induction of anaesthesia with intravenous alfaxalone or propofol was evaluated in a dose escalation study using 6 dogs. Each dog was dosed at 1x, 2x, 5x, 10x and 20x multiples of the labelled doses (2mg/kg for alfaxalone; 6.5mg/kg for propofol), until apnoea was observed. For each administration, the entire calculated dose was delivered over 1min. All 6 dogs ventilated spontaneously after labelled (1x) doses of each drug but became apnoeic at 5x dose of propofol versus 20x dose of alfaxalone. For propofol at 2x and 5x doses, 4 and 0 dogs ventilated spontaneously respectively. For alfaxalone at 2x, 5x and 10x doses all 6, 4 and 1 dog ventilated spontaneously, respectively. The median dose which induced apnoea was higher for alfaxalone (5x) than for propofol (2x) (p=0.05). We concluded that induction of anaesthesia with propofol is more likely to induce apnoea than with alfaxalone