Postural influence on systemic blood pressure, gas exchange, and acid/base status in the term-pregnant bitch during general anesthesia
Probst, C.W.; Webb, A.I.
American Journal of Veterinary Research 44(10): 1963-1965
1983
ISSN/ISBN: 0002-9645 PMID: 6638653 Document Number: 215919
Effects of positioning were studied in 7 bitches during general anaesthesia at about 60 days of gestation. Five positions (right and left lateral recumbency, right and left 10 degrees to 15 degrees tilt toward lateral recumbency, and dorsal recumbency) were examined. Anaesthesia was induced with thiamylal sodium and was maintained with halothane and nitrous oxide in oxygen. Direct arterial blood pressure, arterial blood gases, pH, base excess, heart rate, respiratory rate, and a lead II ECG were recorded from the bitches during each position. Effects of positioning for each bitch during general anaesthesia were reexamined after the bitch had weaned its pups; therefore, each bitch served as its own control. Maternal posture did not effect any measured parameters in bitches before or after parturition. Pregnancy affected every parameter except heart rate. Pregnant bitches had a lower systolic blood pressure, lower oxygen tension, lower PCV, higher CO2 tension, higher respiratory rate, and a more severe acidosis than after parturition. Supine hypotension did not occur. Tilting the bitch 10 degrees to 15 degrees toward right or left lateral recumbency or true lateral recumbency was no better than dorsal recumbency for performing caesarean sections under general anaesthesia.