Jahr J, Grände P O
Department of Physiology, University of Lund, Sweden.
Acta Physiol Scand. 1997 Feb;159(2):93-100. doi: 10.1046/j.1365-201X.1997.548320000.x.
The present study analyses the peripheral circulatory effects of pump perfusion on a sympathectomized cat skeletal muscle in terms of effects on segmental vascular resistances (large-bore arterial vessels, arterioles and veins), hydrostatic capillary pressure, capillary filtration coefficient, transcapillary filtration and autoregulation of blood flow. The effect of prostacyclin during pump perfusion was analysed to evaluate whether it interferes with the pump-induced vascular alterations, especially if it reduces transcapillary filtration through its capillary permeability decreasing effect. Pump perfusion initiates a marked vasodilation (from 17.3 to 10.1 PRU), an increase in hydrostatic capillary pressure, and a marked inhibition of myogenic reactivity and of autoregulation of blood flow. There was a slow restoration of vascular tone reaching a steady-state level somewhat below the autoperfusion value within 2 h. Pump perfusion did not change the capillary filtration coefficient, indicating that the capillary permeability was not increased. This implies that short-term pump-induced capillary leakage is more an effect of increase in hydrostatic capillary pressure, perhaps in combination with increased number of open capillaries, than of an increase in capillary permeability. Prostacyclin decreased capillary permeability by at least 22% but simultaneously increased hydrostatic capillary pressure, resulting in an unchanged filtration compared with the situation just after the starting of the pump. The results obtained show that experiments using pump perfusion should be interpreted with care due to the interference with normal peripheral vascular control. The results give reasonable explanations of the lowered blood pressure and transcapillary fluid loss during the clinical use of a heart-lung machine.
本研究从对节段性血管阻力（大口径动脉血管、小动脉和静脉）、毛细血管静水压、毛细血管滤过系数、跨毛细血管滤过和血流自动调节的影响方面，分析了泵灌注对交感神经切除猫骨骼肌的外周循环效应。分析了泵灌注期间前列环素的作用，以评估其是否干扰泵诱导的血管改变，特别是其是否通过降低毛细血管通透性来减少跨毛细血管滤过。泵灌注引发显著的血管舒张（从17.3降至10.1外周阻力单位）、毛细血管静水压升高以及对肌源性反应性和血流自动调节的显著抑制。血管张力在2小时内缓慢恢复，达到略低于自身灌注值的稳态水平。泵灌注未改变毛细血管滤过系数，表明毛细血管通透性未增加。这意味着短期泵诱导的毛细血管渗漏更多是毛细血管静水压升高的结果，可能与开放毛细血管数量增加有关，而非毛细血管通透性增加。前列环素使毛细血管通透性至少降低22%，但同时增加了毛细血管静水压，导致与泵启动后即刻相比滤过无变化。所得结果表明，由于对正常外周血管控制的干扰，使用泵灌注的实验应谨慎解释。这些结果为心肺机临床使用期间血压降低和跨毛细血管液体丢失提供了合理的解释。
