급성빈혈과 장모세혈관 투과성에 관한 연구

Abstract

Massive fluid loss into the intestinal lumen associated with a hypovolemic shock has been regarded as one of the important factors , which aggravate and progress into irreversible state. However , the mechanism of this progress has not been adequately explained. The experiment was designed to investigate the mechanism of intestinal fluid loss. using in vitro intestinal loop preparations of rabbits. During shock, carotid arterial pressure was maintained at 40-50 mmHg by the reservoir technique of Wiggers and the beginning of autoreinfusion of reservoir blood was taken as the start of the irreversible shock. Intestinal loop was perfused with an artific,,1 perfusate (Haemaccel plasma expander. Handok-Hoechst Co.). Five hemodynamic parameters were measured directly: isogravimetric capillary pressure. arterial pressure. venous pressure. venous flow, and luminal flow. Other useful data were obtained from the above measured results: mean capillary pressure, precapillary resistance. postcapillary resistance. total tissue resistance and volume flow coefficient. The following results were obtained. 1. Isogravimetric capillary pressure decreased from 19.5 mmHg of the control group to 12.5 mmHg during shock. This suggested that the capillary permeability increased at the shock state. 2. Mean capillary pressure was always higher in shock than in the control group at various levels of arterial pressures. 3. During shock, precapillary resistance decreased, but postcapillary resistance increased compared with that of control group. Therefore pre-to-postcapillary resistance ratio decreased at the shock state. This might be the reason why mean capillary pressure was elevated and capillary stagnation appeared during the irreversible shock. 4. Total tissue resistance was lower in shock than in control group. This indicated that the hydraulic conductance of tissue increased at the shock state. 5. Volume flow coefficient was much larger in shock than in the control group. Luminal flow showed a Ii'lea rity with the change in the mean capillary pressure at normal condition, but changed exponentially at the shock state From the above results, it was concluded that the intestinal fluid loss at an irreversible shock state resulted from simultaneous increases in tissue pressure and hydraulic conductance of mucosa.