Cormier Y, Sériès F
Unité de Recherche, Centre de Pneumologie, Hôpital and Université Laval, Québec, Canada.
Respir Physiol. 1990 Apr;80(1):103-12. doi: 10.1016/0034-5687(90)90009-n.
Nine mongrel dogs were anesthetized, paralysed, ventilated, and placed in an iron lung. Each animal was transiently connected to a spirometer and the respiratory system compliance measured by applying negative or positive extrathoracic pressures (from -20 cm H2O to +20 cm H2O in 5 cm H2O steps). A sub-lobar bronchus was wedged with a 5.5 mm bronchoscope, and a 5f Swan-Ganz catheter was inserted into the lumen of the bronchoscope; one port served to introduce a 200 ml.min-1 flow of 5% CO2 in air, the other to measure the pressure in the wedged segment. Rcoll was measured with extrathoracic pressures in the iron lung ranging from 0 to -20 cm H2O (NEP) and 0 to +20 cm H2O (PEP) in 5 cm H2O steps, and under expiratory positive airway pressure (EPAP) of 5, 10, 15, and 20 cm H2O. The maximal changes in FRC were an increase of 1009 +/- 49 ml (mean +/- SEM) with NEP and a decrease of 397 +/- 33 ml with PEP. Increasing FRC decreased Rcoll while decreasing FRC markedly increased it. EPAP induced similar decreases in Rcoll as NEP of equal pressure. This effect of EPAP was inhibited by simultaneously applying PEP of equal pressure. We conclude that resistance to collateral flow is highly dependent on lung volume, and that positive airway pressure decreases Rcoll by its effects on lung volume.
9只杂种犬被麻醉、麻痹、通气，并置于铁肺中。每只动物短暂连接到肺活量计，通过施加胸外负压或正压（以5cmH₂O步长从-20cmH₂O到+20cmH₂O）测量呼吸系统顺应性。用5.5mm支气管镜楔入一个肺叶下支气管，并将一根5f Swan-Ganz导管插入支气管镜管腔；一个端口用于引入200ml.min⁻¹的5%二氧化碳空气流，另一个端口用于测量楔入节段的压力。在铁肺中，通过以5cmH₂O步长在0至-20cmH₂O（NEP）和0至+20cmH₂O（PEP）的胸外压力下，以及在5、10、15和20cmH₂O的呼气末正压（EPAP）下测量Rcoll。FRC的最大变化是NEP时增加1009±49ml（平均值±标准误），PEP时减少397±33ml。FRC增加时Rcoll降低，而FRC减少时Rcoll显著增加。EPAP引起的Rcoll降低与等压NEP相似。等压PEP同时应用可抑制EPAP的这种作用。我们得出结论，侧支血流阻力高度依赖于肺容积，气道正压通过其对肺容积的影响降低Rcoll。
