Dogs were randomly allocated to be anesthetized twice , with a 1-week wash-out interval , by means of 2 of 3 possible protocols ( propofol [ 4 mg/kg { 1.8 mg/lb } , n = 6 dogs ] , ketamine [ 2 mg/kg { 0.9 mg/lb } ] and propofol [ 2 mg/kg ; 7 ] , or ketamine [ 5 mg/kg { 2.3 mg/lb } ] and diazepam [ 0.2 mg/kg { 0.09 mg/lb } ; 6 ] ) .