AJP - Heart and Circulatory Physiology, Vol 235, Issue 6 753-H758, Copyright © 1978 by American Physiological Society
Survival and microvascular responses to hemorrhage with three anesthetic combinations
D. L. Wiegman, P. D. Harris, F. N. Miller, R. J. Morff and F. R. Wilmoth
The effects of different anesthetic combinations on the responses to
hemorrhage were investigated while using a single fixed protocol. Small
artery (x +/- SE = 112 +/- 3 micron)) and vein (172 +/- 5 micron) responses
to hemorrhage were quantitated in the cremaster muscle of 38 Sprague-Dawley
rats via closed-circuit television microscopy. Rats were anesthetized
intraperitoneally with pentobarbital (50 mg/kg), urethan (800 mg/kg), and
alpha-chloralose (60 mg/kg), or urethan (600 mg/kg) and alpha-chloralose
(120 mg/kg). After a 15-min control period, arterial blood pressure was
lowered to 30 mmHg and maintained at that level for 60 min via hemorrhage
from the femoral artery. The hemorrhaged blood was then reinfused, and
recovery was monitored for 30 min. Survival was monitored for 7 days. Rats
with heavier body weights (greater than or equal to 160 g) had a
significantly greater survival rate, 81%, than did the lighter weight rats
(less than 160 g), with a 32% survival rate. There were, however, no
statistical differences in survival or microvascular responses among rats
anesthetized with the three combinations of anesthetics. The combined data
for all rats were: survival, 53%; small artery constriction, 45 +/- 2%; and
small vein constriction, 21 +/- 3%.
