Reduced metabolic rate accompanies the hemorrhage-induced hypothermia in conscious rats.
The mechanism for the hemorrhage-induced drop in body temperature is unknown. This study determined the alterations in cutaneous heat exchange and metabolic heat production caused by a moderate hemorrhage in conscious rats. Chronically instrumented rats were subjected to a 16 ml/kg hemorrhage, followed by a 4-h recovery period, while monitoring body core temperature and cutaneous temperature. Cutaneous heat transfer was disrupted by housing the animals at an elevated (28 degrees C) ambient temperature. A separate group of experiments measured the change in oxygen consumption in the post-hemorrhage period. Moderate hemorrhage caused a drop in body core temperature which stabilized at 0.7+/-0.3 degrees C below control in the second hour following hemorrhage. Disruption of cutaneous heat exchange by reducing the thermal gradient did not diminish the hemorrhage-induced hypothermia. Hemorrhage caused a significant decline of oxygen consumption (-0. 21+/-0.05 ml O(2)/g per h). This 16% drop in resting oxygen consumption was prevented by immediately retransfusing the aspirated blood back into the rat. These data indicate that a decrease in metabolic heat production mediates the drop in body core temperature caused by moderate hemorrhage in conscious rats.
Henderson
R A
RA
Department of Biology, East Carolina University School of Medicine, 600 Moye Boulevard, Greenville, NC, USA.
Whitehurst
M E
ME
Morgan
K R
KR
Carroll
R G
RG
D000818:Animals; D001833:Body Temperature Regulation; D003243:Consciousness; D007035:Hypothermia / Q000209:etiology / Q000378:metabolism*; D008297:Male; D010101:Oxygen Consumption; D051381:Rats; D017207:Rats, Sprague-Dawley; D012771:Shock, Hemorrhagic / Q000150:complications* / Q000378:metabolism; D012881:Skin Temperature