Department of Anesthesiology and Intensive Care Medicine, Osaka University Graduate School of Medicine, Suita, Japan.
Department of Anesthesiology, Osaka Women's and Children's Hospital, Izumi, Japan.
Respir Care. 2021 Jan;66(1):1-10. doi: 10.4187/respcare.07880. Epub 2020 Sep 8.
Pendelluft phenomenon is defined as the displacement of gas from a more recruited nondependent (ND) lung region to a less recruited dependent (D) lung region. This phenomenon may cause lung injury. Thus, a lung model for pendelluft was established, and the effects of ventilatory settings on pendelluft were examined.
Two sets of the twin-bellows-type training test lung (TTL) model were utilized. One set of bellows simulated the diaphragm, and the other simulated the lung. One TTL model represented the ND region, and the other represented the D region. The lung bellows were connected to each other and were ventilated with 1 ventilator. The diaphragm bellows were ventilated with 2 synchronized ventilators that regulated pleural pressure levels. We simulated pendelluft by applying different pleural pressure levels to the D and ND bellows. The increment of the tidal volume in the D region from the "no breathing effort" condition was defined as the pendelluft volume. The effects of ventilator settings, such as ventilatory modes, triggering sensitivity, inspiratory pressurization, and inspiratory cycling-off, were examined. The changes in tidal volumes in the D region based on the control settings were compared to assess the severity of pendelluft.
The gas flow from the D region to the ND region was found to be essential in pendelluft, but the severity of this phenomenon was not always proportional to gas flows. The severity increased with the increase in the differences in pleural pressure levels between the ND and D regions, and it was amplified by the difference in lung mechanics between the ND and D regions. However, the ventilator settings had minimal effect on the severity of pendelluft.
The pendelluft was affected by the heterogeneity of lung mechanics and pleural pressure. Furthermore, a minimal association was observed between the ventilator settings and the severity of pendelluft.
Pendelluft 现象被定义为气体从一个募集程度较高的非依赖区（ND）肺部区域向一个募集程度较低的依赖区（D）肺部区域的转移。这种现象可能导致肺部损伤。因此，建立了一种 Pendelluft 肺部模型，并检查了通气设置对 Pendelluft 的影响。
使用两组双胞胎风箱式训练测试肺（TTL）模型。一组风箱模拟膈肌，另一组模拟肺。一个 TTL 模型代表 ND 区，另一个代表 D 区。肺风箱相互连接，并由一台呼吸机进行通气。膈肌风箱由两台同步呼吸机通气，调节胸腔压力水平。我们通过对 D 和 ND 风箱施加不同的胸腔压力来模拟 Pendelluft。将 D 区在“无呼吸努力”条件下的潮气量增加定义为 Pendelluft 量。检查了通气机设置的影响，如通气模式、触发灵敏度、吸气加压和吸气循环关闭。比较基于控制设置的 D 区潮气量的变化，以评估 Pendelluft 的严重程度。
发现 D 区向 ND 区的气体流动是 Pendelluft 的关键，但这种现象的严重程度并不总是与气流成正比。随着 ND 和 D 区之间胸腔压力水平差异的增加，严重程度增加，并且 ND 和 D 区之间的肺力学差异会放大这种现象。然而，通气机设置对 Pendelluft 的严重程度影响很小。
Pendelluft 受肺力学和胸腔压力异质性的影响。此外，通气机设置与 Pendelluft 严重程度之间的关联很小。
