Higher Levels of Spontaneous Breathing Reduce Lung Injury in Experimental Moderate Acute Respiratory Distress Syndrome
Higher Levels of Spontaneous Breathing Reduce Lung Injury in Experimental Moderate Acute Respiratory Distress Syndrome
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DOI：
10.1097/ccm.0000000000000605
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发表时间：
2014-11-01
影响因子：
8.8
通讯作者：
de Abreu, Marcelo Gama
中科院分区：
文献类型：
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作者：
Carvalho, Nadja C.;Gueldner, Andreas;de Abreu, Marcelo Gama
目的：通过建立中度急性呼吸窘迫综合征的实验模型，评价双相正压/压力释放呼吸机不同自主呼吸水平对肺功能和肺损伤的影响。设计：多臂随机实验研究。地点：大学医院研究设施。研究对象：36只幼猪。干预：麻醉、插管、机械通气。反复生理盐水肺灌洗诱发中度急性呼吸窘迫综合征。采用吸气/呼气比为1：1的双相气道正压/压力释放模式。动物随机分为4种自主呼吸水平(每组9只，每分钟6小时)：1)双相正压/气道压力释放模式，0%；2)双相正压/气道压力释放模式，0~30%；3)双相气道正压/气道压力释放模式，30~60%，4)双相正压/气道压力释放模式，>；测量和主要结果：由食道压力时间乘积测量的吸气力与自发呼吸量成正比增加，并伴随着氧合和呼吸系统弹性的改善。与0%的双相气道正压/气道压力释放通气相比，超过60%的双相气道正压/气道压力释放通气导致最低的静脉混合气，以及最高和平均的气道和经肺压力，将呼吸机重新分配到依赖的肺区，降低整个肺的累积弥漫性肺泡损伤评分(中位数[四分位数范围]，11[3-40]比18[2-69]；p<；并降低腹侧肺组织中肿瘤坏死因子-α的水平(中位数[四分位数范围]，17.7pg/mg[8.4-19.8]vs 34.5pg/mg[29.9-42.7]；p<；0.05)。与60%以上的双相气道正压/压力释放模式相比，双相正压/气道压力释放模式在肺功能、炎症和损伤方面的改善模式不如60%。结论：在猪中度急性呼吸窘迫综合征模型中，双相气道正压/气道压力释放模式的自主呼吸量高于临床常见的自主呼吸水平，即占总分钟通气量的30%以上，与保护性控制性机械通气相比，肺损伤减轻，呼吸功能改善。
Objectives: To assess the effects of different levels of spontaneous breathing during biphasic positive airway pressure/airway pressure release ventilation on lung function and injury in an experimental model of moderate acute respiratory distress syndrome.Design: Multiple-arm randomized experimental study.Setting: University hospital research facility.Subjects: Thirty-six juvenile pigs.Interventions: Pigs were anesthetized, intubated, and mechanically ventilated. Moderate acute respiratory distress syndrome was induced by repetitive saline lung lavage. Biphasic positive airway pressure/airway pressure release ventilation was conducted using the airway pressure release ventilation mode with an inspiratory/expiratory ratio of 1:1. Animals were randomly assigned to one of four levels of spontaneous breath in total minute ventilation (n = 9 per group, 6 hr each): 1) biphasic positive airway pressure/airway pressure release ventilation, 0%; 2) biphasic positive airway pressure/airway pressure release ventilation, > 0-30%; 3) biphasic positive airway pressure/airway pressure release ventilation, > 30-60%, and 4) biphasic positive airway pressure/airway pressure release ventilation, > 60%.Measurements and Main Results: The inspiratory effort measured by the esophageal pressure time product increased proportionally to the amount of spontaneous breath and was accompanied by improvements in oxygenation and respiratory system elastance. Compared with biphasic positive airway pressure/airway pressure release ventilation of 0%, biphasic positive airway pressure/airway pressure release ventilation more than 60% resulted in lowest venous admixture, as well as peak and mean airway and transpulmonary pressures, redistributed ventilation to dependent lung regions, reduced the cumulative diffuse alveolar damage score across lungs (median [interquartile range], 11 [3-40] vs 18 [2-69]; p < 0.05), and decreased the level of tumor necrosis factor- in ventral lung tissue (median [interquartile range], 17.7 pg/mg [8.4-19.8] vs 34.5 pg/mg [29.9-42.7]; p < 0.05). Biphasic positive airway pressure/airway pressure release ventilation more than 0-30% and more than 30-60% showed a less consistent pattern of improvement in lung function, inflammation, and damage compared with biphasic positive airway pressure/airway pressure release ventilation more than 60%.Conclusions: In this model of moderate acute respiratory distress syndrome in pigs, biphasic positive airway pressure/airway pressure release ventilation with levels of spontaneous breath higher than usually seen in clinical practice, that is, more than 30% of total minute ventilation, reduced lung injury with improved respiratory function, as compared with protective controlled mechanical ventilation.