RESUMEN
OBJECTIVE: To evaluate the clinical efficacy of dexmedetomidine as a preanesthetic medication administered prior to anesthetic induction with ketamine or propofol and with or without isoflurane for maintenance of anesthesia. DESIGN: Randomized, blinded, controlled clinical trial. ANIMALS: 184 client-owned cats. PROCEDURES: Cats requiring general anesthesia for short or long procedures were assigned to receive 1 of 4 preanesthetic and induction drug combinations (dexmedetomidine and ketamine, placebo [saline {0.9% NaCl} solution] and ketamine, dexmedetomidine and propofol, or placebo and propofol). Cats undergoing long procedures received isoflurane for maintenance of anesthesia. RESULTS: Administration of dexmedetomidine prior to anesthetic induction with ketamine significantly increased the intubation success rate (57/64 [89%]), compared with the success rate for the placebo (4/37 [11 %]); significantly reduced the median induction dose of propofol (≤ 5.1 mg/kg [2.32 mg/lb]), compared with that for the placebo (≤ 10.5 mg/kg [4.77 mg/lb]); and significantly reduced the isoflurane concentration (1.5%) required for anesthesia maintenance, compared with that for the placebo (3.0%). Postoperatively, fewer cats receiving dexmedetomidine required rescue analgesia, and cats had lower pain scores for at least 2 hours after surgery, compared with results for cats receiving the placebo. Heart rate was lower during the procedure and respiratory rate and rectal temperature were lower during and after the procedure for cats receiving dexmedetomidine. More cats that received dexmedetomidine had emesis and pale mucous membranes, compared with the number of cats with those signs that received placebo. CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine as a preanesthetic was efficacious for clinical use in cats requiring general anesthesia.