Lung stress and strain during mechanical ventilation for acute respiratory distress syndrome
Lung stress and strain during mechanical ventilation for acute respiratory distress syndrome
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DOI：
10.1164/rccm.200710-1589oc
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发表时间：
2008-08-15
影响因子：
24.7
通讯作者：
Gattinoni, Luciano
中科院分区：
文献类型：
--
作者：
Chiumello, Davide;Carlesso, Eleonora;Gattinoni, Luciano
基本原理：呼吸机引起的肺损伤是非生理性肺应激的结果（经肺压）和应变目的：确定高原压力和潮气量是否是应力和应变的适当替代物，并量化患者和对照受试者的应力应变关系。方法：术后健康者19例（第1组），内科疾病患者11例（第2组），急性肺损伤患者26例（第3组），24例急性呼吸窘迫综合征患者（第4组）接受呼气末正压（PEEP）试验测量和主要结果：高原气道压力，肺和胸壁弹性，肺应力和应变显着增加，从组I到4，并增加PEEP和潮气量。在每组内，由于肺弹性与呼吸系统弹性比的可变性（范围，0.33 - 0.95），给定的施加气道压力产生很大程度上可变的应力。类似地，对于相同的应用潮气量，由于功能残气量的变异性，亚组内的应变变异性是显著的。因此，低潮气量或高潮气量，如6 ml/kg和12 ml/kg，可在每个亚组中显著比例的患者中产生相似的应力和应变。相反，应力应变比--即比肺弹性--在所有亚组中是相似的（第1组至第4组分别为13.4 +/-3.4、12.6 +/-3.0、14.4 +/-3.6和13.5 +/-4.1 cm H2O; P = 0.58），不随PEEP和潮气量变化。高原压力和潮气量不足以替代肺应力和应变。
Rationale: Lung injury caused by a ventilator results from non physiologic lung stress (transpulmonary pressure) and strain (inflated volume to functional residual capacity ratio).Objectives: To determine whether plateau pressure and tidal volume are adequate surrogates for stress and strain, and to quantify the stress to strain relationship in patients and control subjects.Methods: Nineteen postsurgical healthy patients (group 1), 11 patients with medical diseases (group 2), 26 patients with acute lung injury (group 3), and 24 patients with acute respiratory distress syndrome (group 4) underwent a positive end-expiratory pressure (PEEP) trial (5 and 15 cm H2O) with 6, 8, 10, and 12 ml/kg tidal volume.Measurements and Main Results: Plateau airway pressure, lung and chest wall elastances, and lung stress and strain significantly increased from groups I to 4 and with increasing PEEP and tidal volume. Within each group, a given applied airway pressure produced largely variable stress due to the variability of the lung elastance to respiratory system elastance ratio (range, 0.33-0.95). Analogously, for the same applied tidal volume, the strain variability within subgroups was remarkable, due to the functional residual capacity variability. Therefore, low or high tidal volume, such as 6 and 12 ml/kg, respectively, could produce similar stress and strain in a remarkable fraction of patients in each subgroup. In contrast, the stress to strain ratio-that is, specific lung elastance-was similar throughout the subgroups (13.4 +/- 3.4, 12.6 +/- 3.0, 14.4 +/- 3.6, and 13.5 +/- 4.1 cm H2O forgroups 1 through 4, respectively; P = 0.58) and did not change with PEEP and tidal volume.Conclusions: Plateau pressure and tidal volume are inadequate surrogates for lung stress and strain.