Effects of medetomidine-midazolam, acepromazine-butorphanol, and midazolam-butorphanol on induction dose of thiopental and propofol and on cardiopulmonary changes in dogs.
OBJECTIVE
To evaluate dose-sparing effects of medetomidine-midazolam (MM), acepromazine-butorphanol (AB), and midazolam-butorphanol (MB) on the induction dose of thiopental and propofol and to examine cardiopulmonary changes in dogs.


METHODS
23 healthy Beagles.


METHODS
Dogs were administered MM, AB, MB, or physiologic saline (0.9% NaCI) solution (PS) IM, and anesthesia was induced with thiopental or propofol. Cardiopulmonary measurements were obtained before and after administration of medication and 0, 5, 10, and 15 minutes after endotracheal intubation.


RESULTS
Induction doses were reduced significantly by preanesthetic administration of MM, AB, and MB (thiopental, 20, 45, and 46% after administration of PS; propofol, 42, 58, and 74% after administration of PS, respectively). Recovery time in dogs administered MM-thiopental or MM-propofol and AB-propofol were significantly prolonged, compared with recovery time in dogs administered PS-thiopental or PS-propofol. Relatively large cardiovascular changes were induced by administration of MM, which were sustained even after the induction of anesthesia. Administration of AB and MB induced cardiovascular changes during and immediately after endotracheal intubation that were significantly decreased by induction with thiopental or propofol. However, mild hypotension developed with AB-propofol. Apnea was observed in dogs administered MM during induction of anesthesia, but most respiratory variables did not change significantly.


CONCLUSIONS
Preanesthetic medication with MM greatly reduced the anesthesia induction dose of thiopental and propofol but caused noticeable cardiopulmonary changes. Preanesthetic medication with AB and MB moderately reduced the induction dose of thiopental and propofol and amelio rated cardiovascular changes induced by these anesthetics, although AB caused mild hypotension.
Kojima
Kentaro
K
Laboratory of Veterinary Surgery, Graduate School of Agricultural and Life Sciences. The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Nishimura
Ryohei
R
Mutoh
Tatsushi
T
Hong
Sung-Hyeok
SH
Mochizuki
Manabu
M
Sasaki
Nobuo
N
D000075:Acepromazine / Q000008:administration & dosage / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002077:Butorphanol / Q000008:administration & dosage / Q000494:pharmacology; D002302:Cardiac Output / Q000187:drug effects; D004285:Dogs / Q000502:physiology*; D004359:Drug Therapy, Combination; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D020926:Medetomidine / Q000008:administration & dosage / Q000494:pharmacology; D008874:Midazolam / Q000008:administration & dosage / Q000494:pharmacology; D011229:Preanesthetic Medication / Q000379:methods; D015742:Propofol / Q000494:pharmacology*; D011897:Random Allocation; D012119:Respiration / Q000187:drug effects*; D013874:Thiopental / Q000494:pharmacology*
D000701:Analgesics, Opioid; D018686:Anesthetics, Intravenous; D006993:Hypnotics and Sedatives; D000075:Acepromazine; D013874:Thiopental; D020926:Medetomidine; D002077:Butorphanol; D008874:Midazolam; D015742:Propofol