A comparison of the effects of propofol and etomidate on the induction of anesthesia and on cardiopulmonary parameters in dogs

Objective To determine the effects of propofol or etomidate on induction quality, arterial blood pressure, blood gases, and recovery quality in normal dogs. Study design Randomized, blinded trial. Animals Eighteen purpose-bred adult Beagles. Methods Dogs were randomly assigned to receive propofol at 8 mg kg(-1) or etomidate at 4 mg kg(-1) intravenously (IV) administered to effect. Midazolam was administered at 0.3 mg kg(-1) IV as pre-medication at least 1 minute prior to induction. Direct arterial blood pressure, arterial blood gases, and heart rate were obtained at baseline, before induction, after induction, and for every 5 minutes afterwards until the dog began to swallow and the trachea was extubated. The dogs were allowed to breathe room air with the endotracheal tube in place. Results The systolic arterial pressure (SAP) was higher in the etomidate group compared with the propofol group after induction. The SAP and mean arterial pressure (MAP) were higher in the etomidate group compared with the propofol group at 5 minutes. The recovery quality and ataxia score were worse in the etomidate group compared with the propofol group. Time from extubation to sternal recumbency and sternal recumbency to standing was longer in the etomidate group compared with the propofol group. The heart rate, PaCO(2), and HCO(3) were higher in the propofol group compared with the etomidate group after induction. The PaO(2) and SaO(2) were lower in the propofol group compared with the etomidate group after induction. The SAP and MAP were lower in the propofol group at 5 minutes compared with baseline. Conclusion and clinical relevance Propofol caused a decrease in SAP and MAP which was not observed with etomidate. Etomidate caused longer and poorer recoveries than propofol.