Hypothermia from realistic fluid resuscitation in a model of hemorrhagic shock.
OBJECTIVE
To correlate changes in core body temperature with changes in mean arterial pressure (MAP) and cardiac output (CO) and with the administration of room-temperature intravenous fluids in a clinically relevant large-animal model of uncontrolled hemorrhage.


METHODS
Ten swine were subjected to uncontrolled hemorrhage through a flow-monitored shunt placed between the femoral artery and the peritoneal cavity. Animals were randomly assigned to a treatment or a control group. The control group (n=5) received no intravenous fluids. The treatment group (n=5) received 80 mL/kg (3:1 crystalloid/blood loss) ambient-temperature lactated Ringer's solution over a 10-minute resuscitation phase initiated 10 minutes after injury. CO and core body temperature, measured with the use of a pulmonary artery catheter, and MAP were the primary outcomes. We analyzed differences between groups with the use of repeated-measures ANOVA. Change of temperature was analyzed against the change in CO, and against fluid infusion for each interval, by means of regression analysis.


RESULTS
The unresuscitated control animals had no change in core temperature despite profound hemorrhagic shock and hypotension. The animals treated with fluids had a mean 2.6 degrees C decrease in core temperature during fluid resuscitation (95% confidence interval [CI], 1.8 to 3.5). A 1.5 degrees C decrease in core temperature (95% CI, .1 to 2.0) persisted at the end of 60 minutes (40 minutes after fluid resuscitation was discontinued). Core temperatures in control animals were 2.8 degrees C lower than those in treated animals after fluid resuscitation (95% CI, .8 to 4.8). Decreases in core temperature correlated with fluid infusion (beta=-35.2 mL/kg x degrees C, R2=.75) and increases in CO (beta=-1.46 L/min x degrees C, R2=.69).


CONCLUSIONS
Ambient-temperature crystalloid resuscitation in a clinically relevant large-animal model of hemorrhagic shock causes small decreases in core body temperature. Resuscitation rather than shock is the main cause of decreased body temperature in this model.
Silbergleit
R
R
Department of Emergency Medicine, George Washington University, Washington, DC, USA.
Satz
W
W
Lee
D C
DC
McNamara
R M
RM
D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure; D002302:Cardiac Output; D004195:Disease Models, Animal; D005069:Evaluation Studies as Topic; D005440:Fluid Therapy / Q000009:adverse effects*; D007035:Hypothermia / Q000209:etiology*; D016014:Linear Models; D011446:Prospective Studies; D011897:Random Allocation; D012044:Regression Analysis; D012771:Shock, Hemorrhagic / Q000628:therapy*; D013552:Swine