Department of Perioperative Medicine, Intensive Care and Emergency, Cattinara Hospital, Trieste University School of Medicine, Strada di Fiume 447, 34139, Trieste, Italy.
Intensive Care Med. 2010 Dec;36(12):2125-31. doi: 10.1007/s00134-010-1993-3. Epub 2010 Aug 6.
To demonstrate in a two-compartment heterogeneous mechanical model of the lung how different loads applied to one compartment, while the other is kept constant, would modify gas distribution between the two pathways under high-frequency percussive ventilation (HFPV). Additionally, these results were compared with those generated in the same model by pressure-controlled ventilation (PCV).
Analysis was based on a Siemens lung simulator, representing a fixed branch of the system with an elastance equal to 45 cmH(2)O/L and a resistance of 20 cmH(2)O/L/s, and a single-compartment lung simulator, representing a variable pathway of the model, presenting three elastic loads varying between 35 and 85 cmH(2)O/L and three resistive loads varying between 5 and 50 cmH(2)O/L/s. Each simulator represented one compartment of the model connected to a central airway that was ventilated with either a volumetric diffusive respirator (VDR-4; Percussionaire Corporation, Sandpoint, ID, USA) or a Siemens Servo 900c ventilator. Flow and pressures were measured in each branch of the model under nine conditions representing the combinations of three elastic and three resistive loads (variable branch) while the loads in the other pathway were kept constant.
HFPV was able to avoid hyperinflation and reduce tidal volume in a bicompartmental heterogeneous lung model. Under HFPV, gas distribution between the two compartments was not constrained by their time constants. PCV yielded gas distribution as determined by the time constant of each compartment.
HFPV accommodated volume distribution without overinflating compartments with low time constants, thus possibly presenting a potential protective behavior in mechanically heterogeneous lungs.
在一个双室异质力学模型中展示，当一个室的负荷发生变化而另一个室保持恒定时，高频脉冲通气（HFPV）如何改变两条通路之间的气体分布。此外，还将这些结果与同一模型中通过压力控制通气（PCV）产生的结果进行了比较。
分析基于西门子肺模拟器，代表系统的一个固定分支，顺应性为 45 cmH(2)O/L，阻力为 20 cmH(2)O/L/s，以及一个单室肺模拟器，代表模型的一个可变通路，具有三个弹性负载，在 35 至 85 cmH(2)O/L 之间变化，三个阻力负载在 5 至 50 cmH(2)O/L/s 之间变化。每个模拟器代表模型的一个室，与中央气道相连，中央气道由容积扩散式呼吸器（VDR-4；Percussionaire Corporation，Sandpoint，ID，USA）或西门子 Servo 900c 呼吸机通气。在模型的每个分支下测量了 9 种情况下的流量和压力，这些情况代表了可变分支中三个弹性和三个阻力负载的组合，而另一个分支的负载保持恒定。
HFPV 能够避免过度充气并减少双室异质肺模型中的潮气量。在 HFPV 下，两个室之间的气体分布不受其时间常数的限制。PCV 根据每个室的时间常数产生气体分布。
HFPV 在不使具有低时间常数的室过度充气的情况下适应了容积分布，因此在机械异质肺中可能具有潜在的保护作用。
