Data_Sheet_2_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：在高频振荡通气（HFOV）作为一种保护性肺通气模式应用于早产儿时，仅当肺容量得到优化时方显其优势。尽管在早产儿的高频振荡通气中提倡采用‘高肺容量策略’，但此策略并未得到精确的定义。目前尚不清楚肺复张的程度应达到何种程度以提供肺保护。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的影响之间的关联。方法：对36只缺乏表面活性物质的124-127天大的羊羔，在出生后持续充气后立即开始高频振荡通气，并将它们分配到以下三种策略之一：（1）不进行肺复张（低肺容量；LLV），（2）中等肺容量（MLV），或（3）高肺容量（HLV）肺复张策略。测量了气体交换和肺容量随时间的变化。通过尸检压力-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：与肺复张组相比，LLV组中有更多动物发生了气胸。肺复张组的气体交换优于LLV组。LLV组的总肺容量倾向于较低。其他肺损伤参数没有差异。结论：在高频振荡通气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仅有适度的影响。在HLV组中，旨在进行更广泛的肺复张时，气体交换得到改善，但并未影响肺损伤。