Effects of a microdose of medetomidine on diazepam-ketamine induced anesthesia in dogs.
OBJECTIVE
To evaluate cardiorespiratory and anesthetic effects of a microdose of medetomidine hydrochloride on diazepam-ketamine (DK) hydrochloride induced anesthesia in dogs.


METHODS
Randomized crossover study.


METHODS
6 two-year-old healthy female dogs.


METHODS
A study was designed to compare quality of anesthetic induction, recovery, analgesia, muscle relaxation, duration of immobilization, and ease of endotracheal intubation between diazepam-ketamine-medetomidine (DKM) and diazepam-ketamine induced anesthesia in 6 dogs. Diazepam (0.25 mg/kg [0.114 mg/lb] of body weight, i.v.) and ketamine (5 mg/kg [2.27 mg/lb], i.v.) with or without a microdose of medetomidine (5 micrograms/kg, i.v.) were administered to dogs. A baseline ECG was obtained, and baseline measurements of arterial blood gas tensions, arterial pressures, heart and respiratory rates, and minute volume were taken before drug administration. All measurements were repeated again 5, 10, 20, and 30 minutes after drug administration. Endotracheal intubation was attempted 1 minute after drug administration and then again 5, 10, 20, and 30 minutes after drug administration. Analgesia was evaluated by tail clamp and needle prick testing.


RESULTS
Medetomidine improved quality of anesthetic induction, ease of endotracheal intubation, and extended duration of analgesia and lateral recumbency in anesthetized dogs. The addition of medetomidine to DK increased blood pressure and decreased heart and respiratory rates and minute volume. Hypoxemia was observed in 1 dog after DKM induced anesthesia.


CONCLUSIONS
Administration of a microdose of medetomidine provides a useful adjunct to DK induced anesthesia in dogs. Oxygen insufflation is recommended for a minimum of the first 5 minutes of DKM induced anesthesia.
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610-0136, USA.
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Nicklin
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D000759:Adjuvants, Anesthesia; D000316:Adrenergic alpha-Agonists; D000698:Analgesia / Q000662:veterinary; D018712:Analgesics, Non-Narcotic; D000758:Anesthesia / Q000592:standards / Q000662:veterinary*; D000777:Anesthetics; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D018592:Cross-Over Studies; D003975:Diazepam; D004285:Dogs / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006993:Hypnotics and Sedatives; D007093:Imidazoles; D007442:Intubation, Intratracheal / Q000662:veterinary; D007649:Ketamine; D020926:Medetomidine; D010100:Oxygen / Q000097:blood; D012119:Respiration / Q000187:drug effects; D013997:Time Factors
D000759:Adjuvants, Anesthesia; D000316:Adrenergic alpha-Agonists; D018712:Analgesics, Non-Narcotic; D000777:Anesthetics; D006993:Hypnotics and Sedatives; D007093:Imidazoles; D002245:Carbon Dioxide; D007649:Ketamine; D020926:Medetomidine; D003975:Diazepam; D010100:Oxygen