Effects of anesthesia on a model of uncontrolled hemorrhage in rats.
OBJECTIVE
Excessive blood loss in a rat model of uncontrolled hemorrhage has been attributed to the vasodilatory effects of a droperidol-ketamine mixture used for anesthesia. The present study compared responses to droperidol-ketamine and pentobarbital with those responses of a control group without anesthesia during uncontrolled hemorrhage.


METHODS
Prospective, randomized, controlled trial.


METHODS
University surgical research laboratory.


METHODS
Forty-five female Sprague-Dawley rats (210 to 275 g).


METHODS
Rats were randomly divided into three groups of 15 each according to the type of anesthesia: unanesthetized; pentobarbital; and droperidol-ketamine. A 75% tail resection was used to initiate hemorrhage. Mortality, survival time, and blood loss were monitored, and the differences between all three groups were tested using chi 2 test (mortality) and one-way analysis of variance (ANOVA) (survival and blood loss) for statistical significance.


RESULTS
Mean blood loss amounts at 15 mins were 8.9, 13.6, and 22.4 mL/kg for the unanesthetized, pentobarbital, and droperidol-ketamine groups, respectively. Mortality rates for the three groups were 0%, 0%, and 53% at 30 mins and 60%, 33%, and 93% at 90 mins, respectively. Mean survival times for these groups were 94, 135, and 39 mins, respectively.


CONCLUSIONS
An excessive rate of blood loss due to the use of droperidol-ketamine anesthesia renders this model inappropriate for investigation of uncontrolled hemorrhage. The response of rats under pentobarbital anesthesia more closely approximates that of unanesthetized rats. However, the higher mortality rate despite the lesser hemorrhage observed in the latter group seems to indicate the existence of other factors (in addition to blood loss) that may contribute to the early death of these animals.
Soucy
D M
DM
Department of Surgery, Texas Tech University Health Sciences Center, Lubbock 79430, USA.
Sindlinger
J F
JF
Greene
S P
SP
Barber
A
A
Illner
H
H
Shires
G T
GT
D000704:Analysis of Variance; D000777:Anesthetics / Q000633:toxicity*; D000818:Animals; D004195:Disease Models, Animal; D004329:Droperidol / Q000633:toxicity*; D004338:Drug Combinations; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced*; D007649:Ketamine / Q000633:toxicity*; D010424:Pentobarbital / Q000633:toxicity*; D011446:Prospective Studies; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D000777:Anesthetics; D004338:Drug Combinations; D007649:Ketamine; D010424:Pentobarbital; D004329:Droperidol