Gastrointestinal Tissue Blood Volume Affected by Venous Pressure Change

실혈 후 및 혈압상승 후의 소화기 조직 혈액량 및 산소 섭취량 -제 1 편 정맥혈압과 소화기 조직 혈액량-

Changes in gastrointestinal tissue blood volume induced by variations of venous pressure between 6 and 40 mmHg were studied in 32 rabbits. Venous pressure lowering was produced by withdrawal of appropriate volume of blood and venous pressure elevation was obtained by partial occlusion of intra-thoracic vena cava inferior. Estimation of regional tissue blood volume was performed by means of regional distribution of injected $Cr^{51}-labeled$ red blood cells. The following results were obtained. 1. At the normal control venous pressure value of 18 mmHg, spleen showed the highest value of tissue blood volume expressed on weight basis, namely, $111{\mu}l/gm$, Liver tissue blood volume was $95\;{\mu}l/gm$, small intestine 24 and stomach $21\;{\mu}l/gm$, respectively. 2. Linear relationships were observed between venous pressure change and gastrointestinal tissue blood volume. The coefficients of correlation were: in spleen r=0.723; in liver r=0.791; in stomach r=0.704, respectively. In small intestine the relationship was less clear and r=0.358. Tissue blood volume of extrabdominal tissue, such as M. gastrocnemius was not influenced by venous pressure change. 3. The highest change in tissue blood volume expressed on weight basis was observed in spleen. The liver tissue showed the next highest change. Change in total tissue blood volume, however, was greatest in liver and next greatest in small intestine. This was interpreted by the fact that total weight of these two organs was much greater than that of spleen. 4. The mechanism that the change in tissue blood volume lies in the venous system which has a great compliance was discussed.