Mild hypothermia alters the oxygen consumption/delivery relationship by decreasing the slope of the supply-dependent line.
OBJECTIVE
To evaluate the effect of mild hypothermia on the relationship between systemic oxygen consumption and oxygen delivery.


METHODS
Prospective animal study.


METHODS
University research laboratory.


METHODS
Anesthetized and ventilated rabbits.


METHODS
Rabbits were subjected to stepwise cardiac tamponade to reduce oxygen delivery while body temperature was maintained at 34 degrees C (group H, n = 8) or 39 degrees C (group N, n = 8).


RESULTS
The oxygen consumption/oxygen delivery relationship was analyzed by the dual-line method. The slope of the supply-dependent line was significantly decreased in group H (y = 0.57x + 1.3) compared with that in group N (y = 0.72x + 1.7), indicating that the ability of tissues to extract oxygen was impaired during hypothermia. Consequently, the proportion of the supply-independent area over the entire range of oxygen delivery was decreased in response to hypothermia.


CONCLUSIONS
The potential for tissue hypoxia is likely to be increased during hypothermia when the circulation becomes unstable and oxygen delivery decreases.
Department of Acute Critical Medicine (D-8), Osaka University Medical School, Osaka, Japan.
Jun
J
Oda
Yasuyuki
Y
Kuwagata
Yasushi
Y
Nakamori
Mitsuhiro
M
Noborio
Toshiaki
T
Hayakata
Satoshi
S
Fujimi
Hisashi
H
Sugimoto
D000818:Animals; D002305:Cardiac Tamponade / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D011817:Rabbits; D013223:Statistics as Topic; D013696:Temperature
D010100:Oxygen