200 



PHYSIOLOGY OF INDUCED HYPOTHERMIA 



trolyte excretion. In this study 21 dogs (group 2) were used. They were sub- 

 divided into three subgroups of seven each. Following suitable control observations 

 on water and electrolyte excretion, and on glomerular filtration rate and renal blood 

 flow, the blood flow to the kidney was interrupted by one of three methods. In the 

 animals in subgroup 2 A (fig. 1) the aorta was occluded just proximal to the renal 

 arteries for two hours. Therefore, any blood that circulated through the kidneys 

 following this procedure was due to collateral circulation and retrograde flow into 

 the aorta below the renal arteries. In subgroup 2B, the left renal artery was 

 occluded with a bulldog vascular clamp for two hours without occluding the aorta. 



Mean Blood Pressure 

 Approximately 140 mm. Hg 



Retroperitoneal approach 



Mean Blood Pressure 

 Approximately 28 mm. Hg 



Fig. 1. — Diagrammatic representation of abdominal aorta and renal arteries in the dog showing 

 the points at which the aorta and the left renal artery were occluded. 



