Atelectrauma Versus Volutrauma: A Tale of Two Time-Constants.
Atelectrauma Versus Volutrauma: A Tale of Two Time-Constants.
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Antelectrauma与Volutrauma：两个时刻的故事。
DOI：
10.1097/cce.0000000000000299
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发表时间：
2020-12
影响因子：
--
通讯作者：
Nieman GF
中科院分区：
文献类型：
--
作者：
Bates JHT;Gaver DP;Habashi NM;Nieman GF
补充数字内容可在文本中找到。阐明在机械通气过程中损伤肺产生的肺不电损伤导致的呼吸机诱导肺损伤的程度是如何由气道压力谱的时间和大小决定的。损伤肺的计算模型为探索机械通气参数如何潜在地调节不电损伤和容量损伤提供了一个平台。该模型结合了肺复吸和复吸的时间依赖性，以及呼气时肺排空的时间常数，由呼吸系统的整体顺应性和阻力决定。计算模型。模拟肺正常和急性损伤患者的情景。模拟伤肺保护性低潮气量通气（Low-Vt）在保持固定潮气量和驱动压力的同时，通过呼气末正压的升高避免了肺不电损伤。相比之下，气道压力释放通气通过结合非常短的呼气持续时间（）来避免不电损伤，这既可以防止足够的时间来回收，又可以限制吸气前的最小肺泡压力。模型模拟表明，在该阈值以下，气道压力释放通气可以安全避免电不损伤，同时保持与低vt相当的潮气量和驱动压力。这个阈值受到肺排空时间常数的强烈影响。低vt通气和气道压力释放通气在避免呼吸机引起的肺损伤方面表现出明显不同的策略，主要涉及分别操纵呼气末正压和呼气末正压。可以基于呼出流量值，这可以提供针对患者的保护性通气方法。
Supplemental Digital Content is available in the text. Elucidate how the degree of ventilator-induced lung injury due to atelectrauma that is produced in the injured lung during mechanical ventilation is determined by both the timing and magnitude of the airway pressure profile. A computational model of the injured lung provides a platform for exploring how mechanical ventilation parameters potentially modulate atelectrauma and volutrauma. This model incorporates the time dependence of lung recruitment and derecruitment, and the time-constant of lung emptying during expiration as determined by overall compliance and resistance of the respiratory system. Computational model. Simulated scenarios representing patients with both normal and acutely injured lungs. Protective low-tidal volume ventilation (Low-Vt) of the simulated injured lung avoided atelectrauma through the elevation of positive end-expiratory pressure while maintaining fixed tidal volume and driving pressure. In contrast, airway pressure release ventilation avoided atelectrauma by incorporating a very brief expiratory duration () that both prevents enough time for derecruitment and limits the minimum alveolar pressure prior to inspiration. Model simulations demonstrated that has an effective threshold value below which airway pressure release ventilation is safe from atelectrauma while maintaining a tidal volume and driving pressure comparable with those of Low-Vt. This threshold is strongly influenced by the time-constant of lung-emptying. Low-Vt and airway pressure release ventilation represent markedly different strategies for the avoidance of ventilator-induced lung injury, primarily involving the manipulation of positive end-expiratory pressure and , respectively. can be based on exhalation flow values, which may provide a patient-specific approach to protective ventilation.