REPETITIVE INJECTABLE ANESTHESIA IN A 27-YEAR-OLD HORSE

A 27-year-old horse was anesthetized 3 times a week for 4 weeks, to fa cilitate cobalt therapy of a squamous cell carcinoma in the left paran asal sinus. Limitations of facilities required transport of the anesth etized horse to and from the cobalt therapy room, therefore, injectabl e anesthesia was used. Initially, the horse was preanesthetized with x ylazine (at 1.1 mg/kg IV) and butorphanol (0.04 mg/kg IV). After 3 ane sthetic episodes, the xylazine dose was reduced to 0.4 mg/kg IV and th e butorphanol was deleted from the regimen. Tiletamine-zolazepam (1.1 mg/kg IV) was used for induction and maintenance of anesthesia (althou gh on 2 occasions a bolus of ketamine was used to maintain immobility) . The length of the procedure varied from 10-45 minutes, and the recov ery times to sternal and standing varied from 23-76 and 55-105 minutes respectively. Although numerous complications might be expected given the age of this horse and the physiologic and metabolic demands of re petitive injectable anesthetics, none were observed.