Lai Y L, Wang J, Lai-Fook S J
Division of Pharmacology, College of Pharmacy, University of Kentucky, Lexington 40506, USA.
Lung. 1997;175(6):395-403. doi: 10.1007/pl00007586.
Lung tissue resistance (Rti) measured in air-filled guinea pig lungs by the alveolar capsule technique was a large part of total lung resistance (Rl), and we wondered whether similar results applied to saline-filled lungs. We used the micropuncture method to measure alveolar pressure (Palv) in saline-filled lungs of 21 guinea pigs. Palv and airway opening pressure (Pao) were measured before and after a sudden interruption of flow during an inflation or deflation maneuver. On stopping flow, there was an immediate large change in Pao followed by a smaller slower change in Pao. Palv was nearly constant immediately after flow interruption but followed the slower change in Pao. The initial change in Pao on flow interruption was interpreted as the resistive pressure loss in the airways. The small change in Pao and Palv was interpreted as the pressure loss caused by tissue stress adaptation. Airway resistance (R(aw)) and Rti were obtained by dividing the pressure losses by the flow before the interruption. Rl was the sum of R(aw) and Rti. The calcium blocker nifedipine reduced both R(aw) and Rti and abolished the difference in Rti between inflation and deflation. Values of Rti were 10-29% of Rl. However, with correction for viscosity, Rti predicted in air-filled lungs would dominate Rl.
通过肺泡囊技术在充满空气的豚鼠肺中测得的肺组织阻力（Rti）占总肺阻力（Rl）的很大一部分，我们想知道类似的结果是否适用于充满生理盐水的肺。我们使用微穿刺法测量了21只豚鼠充满生理盐水的肺中的肺泡压力（Palv）。在充气或放气操作过程中流量突然中断前后，测量了Palv和气道开口压力（Pao）。停止流量时，Pao立即发生大幅变化，随后Pao出现较小且较慢的变化。流量中断后，Palv几乎立即保持恒定，但跟随Pao的较慢变化。流量中断时Pao的初始变化被解释为气道中的阻力压力损失。Pao和Palv的小变化被解释为组织应力适应引起的压力损失。气道阻力（R(aw)）和Rti通过将压力损失除以中断前的流量获得。Rl是R(aw)和Rti之和。钙通道阻滞剂硝苯地平降低了R(aw)和Rti，并消除了充气和放气之间Rti的差异。Rti值为Rl的10% - 29%。然而，校正粘度后，在充满空气的肺中预测的Rti将主导Rl。
