Fluid movement in occluded single capillaries of rabbit omentum.

The sequence of transcapillary fluid movement during microocclusion of single capillaries was investigated on the theoretical basis of the Starling hypothesis. For most capillaries studied, the theory agrees reasonably well with the experiments with red cells used as the tags for fluid movement. By analyzing the sequence of the movement of the red cell in one single occlusion, it was possible to calculate the filtration coefficient and the effective pressure. The effective pressure ranged from 28 to 38 cm H2O. Since the arterial pressure in the capillary is about 20 to 30 cm H2O, the calculations suggest that about 10 cm H2O of the effective pressure is contributed by tissue factors, i.e., a negative hydrostatic pressure or a substantial colloidal osmotic pressure in the tissue space or both. The calculated filtration coefficient for the capillaries ranged from 0.01 to 0.07 fi?/(sec fj r cm H2O).