Hypothermia and minimal fluid resuscitation increase survival after uncontrolled hemorrhagic shock in rats.
OBJECTIVE
To test the hypothesis that protective-preservative moderate hypothermia during uncontrolled hemorrhagic shock (UHS) in rats increases survival.


METHODS
Randomized outcome study in rats.


METHODS
UHS phase I of 90 minutes, with initial withdrawal of 3 mL/100 g of blood plus tail amputation, was followed by hemostasis and all-out resuscitation phase II from 90 to 150 minutes, and observation phase III to 72 hours. Forty male rats under light anesthesia and spontaneous breathing were randomized into four groups: Group 1 received no fluid resuscitation during UHS and normothermia (37.5 degrees C) throughout. Group 2 received no fluid resuscitation and hypothermia (30 degrees C) from 15 to 120 minutes. Group 3 received lactated Ringer's solution to maintain mean arterial pressure at 40 mm Hg during UHS and normothermia. Group 4 received lactated Ringer's solution to a mean arterial pressure of 40 mm Hg during UHS and hypothermia from 15 to 120 minutes.


RESULTS
UHS phase I was survived by 0 of 10 rats in group 1, 7 of 10 in group 2, 5 of 10 in group 3, and 10 of 10 in group 4 (p < 0.01 for group 1 vs. 2, 3, or 4; p < 0.05 for group 4 vs. 3). Survival to 72 hours was achieved by 0 of 10 rats in group 1, 3 of 10 in group 2 (p < 0.001 vs. group 1), 1 of 10 in group 3, and 7 of 10 in group 4 (p < 0.001 vs. group 1, and p < 0.01 vs. group 3). All 72-hour survivors were neurologically normal. Necropsies in rats that died early during phase III showed edema and gastrointestinal hemorrhages.


CONCLUSIONS
Moderate hypothermia or limited (hypotensive) fluid resuscitation --best both combined--increases survival during and after UHS in rats.
Kim
S H
SH
Department of Anesthesiology/Critical Care Medicine, University of Pittsburgh Medical Center, Pennsylvania 15260, USA.
Stezoski
S W
SW
Safar
P
P
Capone
A
A
Tisherman
S
S
D000818:Animals; D001794:Blood Pressure; D004195:Disease Models, Animal; D007036:Hypothermia, Induced; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012151:Resuscitation; D012771:Shock, Hemorrhagic / Q000401:mortality / Q000628:therapy*; D015996:Survival Rate