Data_Sheet_1_Lung Recruitment Strategies During High Frequency Oscillatory Ventilation in Preterm Lambs.doc

Background: High frequency oscillatory ventilation (HFOV) is considered a lung protective ventilation mode in preterm infants only if lung volume is optimized. However, whilst a “high lung volume strategy” is advocated for HFOV in preterm infants this strategy is not precisely defined. It is not known to what extent lung recruitment should be pursued to provide lung protection. In this study we aimed to determine the relationship between the magnitude of lung volume optimization and its effect on gas exchange and lung injury in preterm lambs.Methods: 36 surfactant-deficient 124–127 d lambs commenced HFOV immediately following a sustained inflation at birth and were allocated to either (1) no recruitment (low lung volume; LLV), (2) medium- (MLV), or (3) high lung volume (HLV) recruitment strategy. Gas exchange and lung volume changes over time were measured. Lung injury was analyzed by post mortem pressure-volume curves, alveolar protein leakage, gene expression, and histological injury score.Results: More animals in the LLV developed a pneumothorax compared to both recruitment groups. Gas exchange was superior in both recruitment groups compared to LLV. Total lung capacity tended to be lower in the LLV group. Other parameters of lung injury were not different.Conclusions: Lung recruitment during HFOV optimizes gas exchange but has only modest effects on lung injury in a preterm animal model. In the HLV group aiming at a more extensive lung recruitment gas exchange was better without affecting lung injury.

背景：高频振荡通气（HFOV）仅当肺容量得到优化时，才被视为早产儿的一种肺保护性通气模式。然而，尽管在早产儿中提倡采用“高肺容量策略”进行HFOV，但该策略并未得到精确的定义。尚不清楚在何种程度上追求肺复张以提供肺保护。在本研究中，我们旨在确定肺容量优化程度与其对气体交换和肺损伤影响的关联。方法：36只表面活性物质缺乏的124-127天大的羊在出生后立即进行持续膨胀，并被分配到以下三种策略之一：（1）无复张（低肺容量；LLV），（2）中肺容量（MLV），或（3）高肺容量（HLV）复张策略。测量了气体交换和肺容量随时间的变化。通过死后压力-体积曲线、肺泡蛋白漏出、基因表达和病理学损伤评分分析肺损伤。结果：与复张组相比，LLV组中有更多动物发生了气胸。与LLV组相比，复张组的气体交换更优。HLV组的总肺容量趋于较低。其他肺损伤参数没有差异。结论：在HFOV期间进行肺复张优化了气体交换，但对早产动物模型的肺损伤只有轻微影响。在HLV组中，为了达到更广泛的肺复张，气体交换得到改善，而不会影响肺损伤。