Effect of induced-hypothermia on short-term survival after volume-controlled hemorrhage in pigs.
OBJECTIVE
To examine whether induced hypothermia could prolong short-term survival after volume-controlled hemorrhagic shock (HS).


METHODS
Fifteen pigs with systemic heparin underwent blood withdrawal of 30 ml/kg over 15 min under spontaneous breathing with halothane anesthesia. The pigs were divided into three groups of five pigs each: Group 1, hemorrhage plus hypothermia with extracorporeal shunt circulation (ECSC); Group 2, hemorrhage plus normothermia with ECSC; and Group 3, hemorrhage alone. For Groups 1 and 2, arteriovenous ECSC was performed for 20 min during HS. The re-infused shunt blood was cooled down to approximately 15 degrees C in Group 1, whereas it was returned at 37.5 degrees C in Group 2. The pigs in Group 3 had no ECSC and were left at room temperature. All pigs were observed until their death or for a maximum of 240 min.


RESULTS
The mean pulmonary artery temperature (T(pa)) of Group 1 animals decreased to 34.5 degrees C at 15 min after the initiation of ECSC, and thereafter remained at 35.5 degrees C after undergoing ECSC. The T(pa) values for Groups 2 and 3 animals remained at 37.5 degrees C throughout the experiment. All five pigs in Group 1 survived until 240 min, whereas all pigs in Group 2 and 3 of five pigs in Group 3 died before 215 min after blood withdrawal. A life table analysis revealed significantly increased survival in Group 1 compared with Group 2 (P<0.01) and Group 3 (P<0.05).


CONCLUSIONS
In lightly anesthetized pigs during volume-controlled HS, induced hypothermia may prolong their short-term survival for reasons that remain to be clarified.
Takasu
Akira
A
Department of Traumatology and Critical Care Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan. atakasu@me.ndmc.ac.jp
Norio
Hirofumi
H
Gotoh
Yoshitaka
Y
Sakamoto
Toshihisa
T
Okada
Yoshiaki
Y
D000818:Animals; D001831:Body Temperature; D005112:Extracorporeal Circulation; D006439:Hemodynamics; D007036:Hypothermia, Induced; D010100:Oxygen / Q000097:blood; D012119:Respiration; D012771:Shock, Hemorrhagic / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D015996:Survival Rate; D013552:Swine
D010100:Oxygen