Cardiopulmonary effects of a tiletamine-zolazepam combination in sheep.
To assess the effects on heart and lung function, a tiletamine-zolazepam (TZ) anesthetic combination was evaluated in 10 Dorset-type ewes. Ewes were randomly allotted to 2 equal groups. Ewes of groups 1 and 2 were given a single bolus of TZ (12 and 24 mg/kg of body weight, IV, respectively) at time zero. Hemodynamic, pulmonary, and ventilation variables were measured at 15-minute intervals to 120 minutes. Blood gas variables were evaluated at 5-minute intervals for the first 30 minutes, then at 15-minute intervals to 120 minutes. In all sheep, TZ administration induced rapid, smooth induction, with gradual and unremarkable recovery. Anesthesia duration was not significantly different between groups (mean +/- SD, 39 +/- 5 and 40 +/- 14 minutes for groups 1 and 2, respectively). Immediate drug effects included apnea, decreased mean arterial blood pressure, and arterial hypoxemia. Cardiac output was significantly decreased in both groups at all times after drug administration. Significant changes in group-1 ewes included increased pulmonary and systemic vascular resistances and decreased inspired minute ventilation, tidal volume, and respiratory airflow. Significant changes in group-2 ewes included increased systemic vascular resistance and decreased pulmonary arterial pressure, inspired minute ventilation, and respiratory airflow. Both drug dosages induced apneustic breathing patterns and caused significant changes in arterial and venous blood hemoglobin concentrations and PCV. Tiletamine-zolazepam is useful for intermediate-duration anesthesia in sheep.(ABSTRACT TRUNCATED AT 250 WORDS)
Lagutchik
M S
MS
Respiratory Research Branch, Walter Reed Army Institute of Research, Washington, DC 20307-5100.
Januszkiewicz
A J
AJ
Dodd
K T
KT
Martin
D G
DG
D000758:Anesthesia / Q000662:veterinary; D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output / Q000187:drug effects; D004338:Drug Combinations; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000097:blood; D011897:Random Allocation; D012119:Respiration / Q000187:drug effects*; D012472:Salivation / Q000187:drug effects; D012756:Sheep / Q000502:physiology*; D013992:Tiletamine / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects; D015041:Zolazepam / Q000494:pharmacology*
D004338:Drug Combinations; D002245:Carbon Dioxide; D013992:Tiletamine; D015041:Zolazepam; D010100:Oxygen