72 



PHYSIOLOCrY OF INDUCED HYPOTHERMIA 



There was an obvious decrease in glomerular filtration rate and renal plasma flow 

 which progressed more rapidly at lower body temperatures (32 to 28° C.) than at 

 the mild hypothermia level (36 to 34° C). This tendency for the clearances not to 

 decrease at lesser degrees of hypothermia seemed to be roughly proportional to the 

 magnitude of the retained cold-combatting powers. The results obtained on a dog 

 which approximated closely the completely poikilothermic status and which also did 

 not exhibit any postoperative change in Ijasal energy metabolism are charted in 

 figures 9 and 10. The results in this dog perhaps reflect the effects of graded hypo- 

 thermia upon these functions, uncomplicated by other superimposed factors. In 

 both instances the clearances were slightly higher postoperatively but they decreased 

 progressively, in a reasonably straight line fashion, with a progressive decrease in 

 body temperature. 



Tubular maxima for para-aminohippurate were significantly lowered at reduced 



PRE-OPERATIVE 38 36 34 32 30 



DEEP COLONIC TEMPERATURES 



28 



Fig. 9. — Relationsliip of effective renal plasma flow to deep colonic temperature in Dog 504, 

 a preparation which approached the complete poikilotherm. Figures in parentheses indicate num- 

 ber of times clearances were done at that particular core temperature. 



