The problems involved in a temporary occlusion of the porta hepatis to obtain abloodless field in hepatic surgery are twofold: One is a severe congestion of blood inthe portal bed and the other is a anoxia of the liver. This study was undertaken tosearch for a protective procedure that would lessen the portal congestion and alleviatethe untoward effec is of anoxia when a total inflow to the liver is temporarilly occluded, and to investigate the function of the remaining part of the liver after an extensivehepatectomy.
I) Experiment as to the Effect of an Occlusion of the Porta Hepatis on PostoperativeMortality Rate, Biochemical Changes in Blood, Liver Tissue Respiration and Polarography.
Fifty-seven mongrel dogs were divided into 4 groups. In the first group, the portahepatis was clamped for a period of 60 minutes with a simultaneous occlusion of thesuperior mesenteric artery under normothermia. In the second group, an equal combinationof procedures was performed under general hypothermia between 31°C and 28°CIn the third group, the porta hepatis was clamped with a splenofemoral shunting undernormothermia and in the fourth group using the same procedure under hypothermia.The superior procedure among the various combinations of procedures described abovewere evaluated on the basis of postoperative mortality rate and by determining changesin SGOT, SGPT, blood sugar, blood ammonia, blood lactic acid, tissue respiration andtissue polarography of the liver after occlusion of the porta hepatis.
All of the 10 dogs in the first group died after 60 minutes of porta hepatis occlusion.One out of 9 dogs in the second group, one out of 5 dogs in the the third group andone out of 5 dogs in the fourth group died after occlusion. These results suggestedthat the procedure chosen for the first group was not advisable for clinical use, and theremaining procedures, that showed a rather similar mortality rate, were further studied.Hypothermic group, group 2 and 4, generally showed less marked alterations in thetests described above and group 2 showed the least change in blood ammonia level.
To favor a simple technique, lower mortality rate and less marked biochemicalchanges, it was concluded that the occlusion of the port a hepatis with a simultaneousocclusion of the superior mesenteric artery under moderate hypothermia was a practicaland reasonably safe procedure for obtaining a bloodless field in hepatic surgery.
II) Experiment as to the Effect of Extensive Liver Resection on the Function of theRemaining Part of the Liver.
About 50% of liver tissue (left upper, left lower and a half of the central lobe) wasremoved under normothermia in a group of 26 dogs, and also 50% of liver resectionwas performed by using a temporary occlusion of the porta hepatis with a simultaneousocclusion of the superior mesenteric artery under moderate hypothermia in theother group 30 dogs. Effect of resection on the function of the remaining part of theliver was investigated by determining the changes in SGOT, SGPT, blood sugar, BSPand serum protein.
Though the changes in SGOT, SGPT and blood sugar after resection of the liver tissuedid not show any marked difference between two groups, serum protein and BSP test wereless markedly affected by the latter combination of procedures, i.e., liver resection byusing a temporary occlusion of the porta hepatis with a simultaneous occlusion of thesuperior mesenteric artery under hypothermia, than by the former, which is usuallyperformed under normothermia.
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