RENAL FUNCTION— MOVER, MORRIS Axn DE BAKEY 207 



The responses of sodium potassium and water excretion of subgroup 2C were 

 similar to the renal hem()d\-namic effects. In the kidney in which the renal artery 

 was occluded as well as the aorta, urine outjjut and sodium excretion were mark- 

 edly depressed after three days. At the same time, urine volume actually increased 

 in the unoccluded kidney, i.e., the kidney which was ischemic only to the extent of 

 having the aorta occluded. There was no effect on ])lasma sodium and potassium. 



The effect of renal ischemia during hypothermia. Since concurrent occlu- 

 sion of the left renal artery and the aorta produced the most severe renal damage 

 under normothermic conditions (group 2C), this method of ])roducing ischemia 

 was next used for studying the protective effect of hypothermia against renal 

 damage due to renal ischemia. It appears that even with hypothermia for two hours, 

 some depression in renal function occurs, hut the degree of renal damage is not 

 as severe as that observed following ischemia produced by the same method under 

 normothermic conditions. Table I points up the sharp contrast in the observations 

 made under normothermic conditions when glomerular filtration rate was depressed 

 to 8 per cent of the control value and renal blood flow to 7 per cent. These observa- 

 tions indicate that hypothermia would be advantageous when complete occlusion 

 of the circulation to the kidney becomes a necessity during surgical procedures. The 

 protective effect of hypothermia is also seen in figures (S, 9, 10, and 11. These are 

 the gross changes produced under normothermic as compared to h\-pothermic 

 conditions for an equal period of time. The right kidney was subjected to ischemia 

 due to aortic occlusion above the renal arteries whereas the left kidney was sul)- 

 jected to ischemia produced by occlusion of the renal artery as well as the aorta. 

 Under normothermic conditions the left kidney showed severe damage with hemor- 

 rhage into both the cortex and medulla, by comparison to the right one. However, 

 under hypothermic conditions there was very little difference observed between 

 the left and right kidneys. 



SU^IMARY— LABORATORY DATA 



Observations have been made in the laboratory on the effect of hypothermia at 

 different levels of temperature reduction as well as the effect of prolonged hypo- 

 thermia. As the temperature is reduced, there is a progressive reduction in mean 

 l)lood pressure, glomerular filtration rate and renal blood flow. The reduction in 

 glomerular filtration rate is not associated with a concurrent reduction in water and 



TABLE I 



CoMi'.\Risox OF Rkx.m. Damage Due to Ischemia (Aorta Plus Rexal Artery Occlusiox) 

 WITH AXD without Hypothermia — Expressed in Per Cent of Control 



Normothermia Hypothermia 



RiKht Left Right Left 



(unoccluded) (occluded)a (unoccluded) (occluded)* 



Mean blood pressure 102 102 95 95 



Glomerular filtration rate 100 S*" 96 69 



Renal blood fl( )w 88 7" 115 80 



Hematocrit 85 85 106 106 



* Renal artery occluded in addition to occlusion of aorta above the renal arterv for two hours 

 "Statistically significant p<0.05. 



