Hubmayr Rolf D, Kallet Richard H
Pulmonary and Critical Care Medicine Division, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
Respiratory Care Services, Department of Anesthesia and Perioperative Care, University of California, San Francisco at Zuckerberg San Francisco General Hospital, San Francisco, CA.
Respir Care. 2018 Feb;63(2):219-226. doi: 10.4187/respcare.05900.
This review describes the current understanding of the lungs' response to deforming stress under conditions of both normal physiology and acute lung injury. Several limiting assumptions are needed to infer lung parenchymal stress and strain from airway pressure, volume, and flow data from mechanically ventilated patients with injured lungs. These assumptions include the effects of the chest wall on lung-surface pressure, its topographical distribution, and the effects of non-uniform tissue properties on local parenchymal stresses. In addition, there is a spectrum of biophysical lung injury mechanisms that involves normal as well as tangential alveolar wall stresses. To these are added important secondary effects on pulmonary vascular resistance and right heart function. Understanding both the assumptions of lung mechanics and the scope of injury mechanisms operating during ARDS is necessary to interpret the results of clinical trials that inform prevailing ventilator-management guidelines. The implications issuing from these 3 topics inform a safer approach to setting and adjusting the ventilator to minimize the risk of ventilator-induced lung injury. This is enumerated in a 5-step approach that can be used to guide ventilator management of unstable patients with severe lung injury.
这篇综述描述了目前对于在正常生理状况和急性肺损伤情况下肺对变形应力反应的理解。从机械通气的肺损伤患者的气道压力、容积和流量数据推断肺实质应力和应变需要几个有限的假设。这些假设包括胸壁对肺表面压力的影响、其地形分布以及非均匀组织特性对局部实质应力的影响。此外，存在一系列生物物理性肺损伤机制，涉及正常以及切向肺泡壁应力。除此之外，对肺血管阻力和右心功能还有重要的继发影响。理解肺力学的假设以及急性呼吸窘迫综合征（ARDS）期间起作用的损伤机制范围对于解释为现行通气管理指南提供依据的临床试验结果很有必要。这三个主题产生的影响为设置和调整呼吸机以将呼吸机诱导性肺损伤风险降至最低提供了更安全的方法。这在一个可用于指导严重肺损伤不稳定患者通气管理的五步方法中进行了列举。
