To evaluate the cardiorespiratory effects of IV administration of propofol ( 4 mg/kg ) , ketamine hydrochloride and propofol ( 2 mg/kg each ; K-P ) , or ketamine hydrochloride ( 5 mg/kg ) and diazepam ( 0.2 mg/kg ; K-D ) before and after induction of anesthesia ( IoA ) in dogs sedated with acepromazine maleate and oxymorphone hydrochloride .