Background

In the adult dog, the combination medetomidine 30 ug/kg and propofol 0.2 mg/kg/min was known to provide a sufficient surgical anesthesia. However, the little data are available concerning anesthetic effects in puppies treated with medetomidine and propofol.

Aims

This study was performed to evaluate anaesthetic effects of variable infusion rates of propofol in beagle puppies premedicated with medetomidine.

Materials and Methods

After medetomidine premedication (30ug/kg) and propofol induction (2 mg/kg), dogs were maintained with 0.2 mg/kg/min (P0.2), 0.4 mg/kg/min (P0.4), 0.6 mg/kg/min (P0.6), and 0.8 mg/kg/min (P0.8) of propofol infusion for 90 minutes. Rectal temperature, heart rate, respiratory rate, pedal reflex, echocardiogram, propofol concentration, arterial pressure, blood gas analysis and recovery times were recorded.

Results

The changes of heart rate, systolic pressure, rectal temperature and pH after propofol infusion were not significant. Respiratory rate and PO₂ were significantly decreased in the P0.6 and P0.8. PCO₂ were significantly increased in the P0.6 and P0.8. Propofol concentrations were increased in dose-dependent manner, and were significantly increased after 30 minutes in P0.6 and P0.8. Surgical anaesthesia determined by pedal reflex were produced in P0.6 and P0.8

Conclusion

In puppies, infusion with 0.6 or 0.8 mg/kg/min of propofol produced a surgical anaesthesia. However, their application should be cautious in puppies because of changes in blood gas and heart failure.