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研擬體外儲筒設計代替稱重設計及容積描記器以連續紀錄組織容積之變化
The Design of Reservoir Method Superseding the Gravimetric and Plethysmographic Techniques for Continuous Monitoring of Tissue Volume Changes
摘要
血流動力以及微循環的研究中，連續測量組織之容積變化是一種重要的技術，傳統使用的稱重法（gravimetric technique）以及容積描記器（plethysmographic technique）雖然構思巧妙，但在技術上有若干不便，而且應用上有許多限制。在這一論文中，描寫一種新設計的發展，利用體外儲筒以連續記錄組織中容積的變化。當一器官以恆定血流灌注時，靜脈之出流收集於一儲筒，儲筒經特殊設計，可以準確而靈敏地測量其內之血量變化，如果以幫浦由儲筒打出等於流入筒中之血流量，則儲筒內之容積維持不變，此時使得器官內液量（血量及組織間液量）發生變化之任何生理及藥理作用，亦將使得儲筒內之血量呈現相同而反向之變化。另外設計兩套不同的血壓調節系統，便由恆定血流灌注改換為恆定血壓灌注，因為調節統系內之血量維持不變，任何灌注壓或灌注血流的變動中，儲筒內血量之反向變化亦反映組織中之容積變化。此一構想及設計利由狗小腸之實驗加以證明，比較二種方法測量小腸液量變化：（1）直接稱重法。（2）新設計儲筒法，實驗之生理及藥理作用包括：（甲）提高靜脈壓。（乙）變化動脈灌注情況。（丙）注射血管作用藥物。每一實驗均顯示儲筒內之血量變化相等於組織之容積變化，只是方向相反而已。此一體外儲筒的新設計也是構思巧妙，而且至少有下列優點：（1）不必分離器官，也可保持神經完整，節省動物實驗製備之時間，在急性動物實驗中，節省時間也就是使實驗的情況較接近正常。（2）以前不易由稱重法或容積描記器加以研究的器官，如腦、胃、肝等均可容易由儲筒法來實驗。（3）動態的器官，如跳動之心臟或運動之骨骼肌均可容易由儲筒法加以研究。
關鍵字
無資料並列摘要
The conventional use of gravimetric or plethysmographic method for continous monitoring of tissue volume changes has some inherent technical problems and limitations. A new method using extracorporal reservoir is devised for indirect measurement of tissue volume changes. When the tissue is perfused with constant flow and the venous outflow is collected in a reservoir, the reservoir volume can be kept constant by pumping out equal amount of blood entering the reservoir. Under this condition, every perturbation causing a change in tissue volume will result in a reservoir volume change of the opposite direction. Two different sets of pressure regulating system are also devised for the control of arterial perfusion pressure. Since volume change is not allowed to occur inside the regulating system, the design still guarantees that reservoir volume change of the opposite direction reflects the tissue volume change during alteration of arterial perfusion pressure. The designs are tested in 6 canine ileum segments by comparing the extracorporeal reservoir volume with the tissue volume recorded with direct gravimetric measurement. Experimental trials include venous pressure elevation, arterial perfusion changes and intra-arterial infusion of vasoactive agents. The tests indicate that the tissue volume changes can be faithfully measured from the reverse change in reservoir volume. We also discuss the technical advantages and possible applications of the reservoir method in the realm of hemodynamic and microcirculatory studies.