Abstract
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.
Highlights
Despite the increasing use of non-invasive respiratory support ∼45% of preterm infants < 28 weeks of gestation still require invasive mechanical ventilation [1]
Alveolar overdistension resulting from large tidal volumes during mechanical ventilation has been identified as a risk factor for ventilator induced lung injury (VILI)
This has been shown in the meta-analysis of large trials of preterm infants receiving first-intention high-frequency oscillatory ventilation (HFOV), which conclusively show that a high-lung volume strategy is needed for HFOV to be safe and efficacious [7, 8]
Summary
Despite the increasing use of non-invasive respiratory support ∼45% of preterm infants < 28 weeks of gestation still require invasive mechanical ventilation [1]. Alveolar overdistension resulting from large tidal volumes (volutrauma) during mechanical ventilation has been identified as a risk factor for VILI For this reason, high-frequency oscillatory ventilation (HFOV), which by design delivers tidal volumes smaller than dead space, is considered a lung protective ventilation mode [4, 5]. Lung protection during HFOV can only be obtained if existing atelectasis is reversed This has been shown in the meta-analysis of large trials of preterm infants receiving first-intention HFOV, which conclusively show that a high-lung volume strategy is needed for HFOV to be safe and efficacious [7, 8]. 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
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