HYPOTHERMIA AND TEMPORARY OCCLUSION OF THE 

 HEPATIC CIRCULATION 



NORMAN E. SHUMWAY* and F. JOHN LEWIS 



A need has long existed for increasing the scope of cancer surgery to inchide 

 ablation of the right lobe of the liver. Lortat-Jacob in 1952 reported the first 

 successful right hepatic lobectomy.^ Since then, a growing literature has outlined a 

 variety of techniques for excising the right lobe of the liver.-' ^' '- ' Despite the 

 efforts of Elias to ascribe a segmental unit to the surgical anatomy of the human 

 liver,** extirpation of the right lobe necessarily involves cutting across a large 

 vascular area. It is clear that the hazard of extreme blood loss from this maneuver 

 could be circumvented by occluding temporarily both the afferent and efferent 

 vasculature of the liver. 



Hypothermia has been demonstrated to reduce splanchnic blood flow and liver 

 function without significant deleterious effects related to cold;' hence, the use of 

 hypothermia to gain sufficient time for massive hepatic resections on a bloodless 

 liver seemed a promising avenue for investigation. 



That the experimental animal at normal temperature can tolerate only brief 

 periods of occlusion of the structures in the porta hepatis has been recognized for 

 years.« The relative importance of the hepatic artery and portal vein and the spe- 

 cific role of each are problems still under scrutiny although considerable informa- 

 tion is now at hand. 



Wolbach in 1909 described the presence of anaerobic, spore-bearing bacteria in 

 the normal canine liver.^ This work permitted Markowitz ultimately to assign to 

 the hepatic artery in the dog the function of maintaining oxygen tension in the 

 liver high enough to prevent proliferation of bacteria.^° Successful transfer of this 

 bacteriostatic function to penicillin after ligation of the hepatic artery was the cru- 

 cial laboratory evidence.^^ 



Doubtless the portal vein can contribute oxygen to hepatocellular oxygen tension 

 in the dog because some animals will survive hepatic artery occlusion without 

 penicillin.^- In these dogs arterial blood reaches the liver via hepatic branches of 

 the phrenic arteries, but subsequent occlusion of the portal vein results in death 

 and indicates that the contribution of oxygen from portal venous blood may be 

 critical under such circumstances. Nonetheless, protection of the dog from death 

 due to liver failure depends primarily on the integrity of the hepatic artery while 

 occlusion of the portal vein, though harmless to the liver, is disastrous because of 

 intestinal infarction and exsanguination of the dog into his abdominal viscera. 



In the absence of any feasible method for bypassing the liver it is necessary to 

 occlude not only the hepatic artery and portal vein but also the vena cava both 

 above and below the liver in order to secure a bloodless operative field and prevent 

 air embolism to the heart. Occlusion of the inferior vena cava above the liver is 

 not tolerated for more than a few minutes unless the aorta is clamped at the same 

 or preferably at a higher level. Obstruction of the thoracic aorta introduces, then, 



*U.S.P.H.S. Research Fellow of the National Heart Institute. 



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