Cardiorespiratory effects of four alpha2-adrenoceptor agonist-ketamine combinations in captive red wolves.
OBJECTIVE
To evaluate the cardiopulmonary effects of immobilizing doses of xylazine-ketamine (XK), medetomidine-ketamine (MK), medetomidine-ketamine-acepromazine (MKA), and medetomidine-butorphanol-ketamine (MBK) in captive red wolves.


METHODS
Prospective study.


METHODS
32 adult captive red wolves.


METHODS
Wolves were randomly assigned to 1 of 4 treatment groups: XK, MK, MKA, or MBK. Physiologic variables measured included heart rate, blood pressure, respiratory rate, tidal volume, oxygen-hemoglobin saturation (Spo2), end-tidal CO2, arterial blood gases, and rectal temperature. Induction time, muscle relaxation, and quality of recovery were assessed.


RESULTS
Heart rates were lower in wolves in the MBK group than for the other groups. All 4 drug combinations induced considerable hypertension, with diastolic pressures exceeding 116 mm Hg. Blood pressure was lowest in wolves receiving the MBK combination. Respiratory rate was significantly higher in wolves receiving XK, MK, and MKA. Tidal volumes were similar for all groups. Wolves receiving XK, MK, and MKA were well-oxygenated throughout the procedure (SPo2 > 93%), whereas those receiving MBK were moderately hypoxemic (87% < Spo2 < 93%) during the first 20 minutes of the procedure. Hyperthermia was detected initially following induction in all groups.


CONCLUSIONS
The alpha2-adrenoceptor agonist-ketamine combinations provide rapid reversible anesthesia for red wolves but cause severe sustained hypertension. Such an adverse effect puts animals at risk for development of cerebral encephalopathy, retinal hemorrhage, pulmonary edema, and myocardial failure. Although the MBK combination offers some advantages over the others, it is advised that further protocol refinements be made to minimize risks associated with acute hypertension.
Sladky
K K
KK
Environmental Medicine Consortium, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA.
Kelly
B T
BT
Loomis
M R
MR
Stoskopf
M K
MK
Horne
W A
WA
D000075:Acepromazine / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000701:Analgesics, Opioid / Q000494:pharmacology; D000778:Anesthetics, Dissociative / Q000494:pharmacology*; D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature; D002077:Butorphanol / Q000494:pharmacology; D003247:Conservation of Natural Resources; D004562:Electrocardiography / Q000662:veterinary; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D020926:Medetomidine / Q000494:pharmacology; D010092:Oximetry / Q000662:veterinary; D011446:Prospective Studies; D012119:Respiration / Q000187:drug effects; D019596:Wolves / Q000502:physiology*; D014991:Xylazine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000701:Analgesics, Opioid; D000778:Anesthetics, Dissociative; D014991:Xylazine; D000075:Acepromazine; D007649:Ketamine; D020926:Medetomidine; D002077:Butorphanol