Watson P D
Am J Physiol. 1982 Apr;242(4):H512-9. doi: 10.1152/ajpheart.1982.242.4.H512.
The development of osmotic pressure, following the addition of bovine serum albumin (BSA) to the perfusate, was measured in an isogravimetric cat hindlimb fully dilated with papaverine. The changes in colloid osmotic pressure were followed by recording the changes in venous pressure (PVI) necessary to maintain constant weight. Capillary filtration coefficient (CFC) and vascular compliances were calculated from weight changes following steps in venous pressure. Venous BSA levels reached arterial within 1 min, and PVI reached a new steady state 13.1 +/- 0.9 (SE) min (n = 9 in 6 limbs) after adding BSA. This apparent delay in the development of the osmotic pressure agrees with earlier reports. However, when the BSA was added under constant venous pressure conditions, the fluid reabsorption reached its maximum rate within 1.5 min. The data suggest that the BSA is osmotically fully effective after the capillary washin. The slowness of the rise of PVI in the isogravimetric state is probably caused by the time necessary to absorb sufficient fluid from the interstitium to raise the capillary pressure to a level that balances the increased oncotic pressure. A mathematical model supports this explanation.
在罂粟碱充分扩张的等重猫后肢中，测量向灌注液中添加牛血清白蛋白（BSA）后渗透压的变化。通过记录维持恒定体重所需的静脉压（PVI）变化来跟踪胶体渗透压的变化。根据静脉压变化后的体重变化计算毛细血管滤过系数（CFC）和血管顺应性。静脉BSA水平在1分钟内达到动脉水平，添加BSA后，PVI在13.1±0.9（SE）分钟（6只肢体中的9只）达到新的稳定状态。渗透压发展的这种明显延迟与早期报告一致。然而，当在恒定静脉压条件下添加BSA时，液体重吸收在1.5分钟内达到最大速率。数据表明，毛细血管冲洗后BSA在渗透方面完全有效。等重状态下PVI上升缓慢可能是由于从间质中吸收足够液体以将毛细血管压力提高到平衡增加的胶体渗透压水平所需的时间。一个数学模型支持这一解释。
