Preterm infants on high-frequency oscillatory ventilation: electrical impedance tomography during lung recruitment.

BACKGROUND

We introduce a novel physiological parameter derived from electrical impedance tomography (EIT) to evaluate oxygenation-guided lung recruitment maneuvers in preterm infants on high-frequency oscillatory ventilation (HFOV).

METHODS

In this prospective observational study, EIT was performed during a single, stepwise oxygenation-guided lung recruitment maneuver in extremely preterm infants. At each step of continuous distending pressure (CDP), we calculated the median oscillations in the aerated region (MOR), defined as the median of oscillatory impedance amplitudes within the air-containing region multiplied by the number of pixels in that region. Recruitability was determined by a ≥15% increase in MOR or oxygenation (S/F-ratio) during deflation compared to inflation at any CDP. Gas exchange parameters were compared between lungs identified as recruitable for MOR or oxygenation.

RESULTS

Of the 56 EIT measurements from 47 infants (mean weight 685 ± 140 g) analyzed, 43 lungs were recruitable by oxygenation criteria, but only 23 met recruitability criteria based on MOR. MOR-recruitable maneuvers significantly improved transcutaneous pCO by 4.8 mmHg, while non-recruitable maneuvers showed no change.

CONCLUSIONS

The novel EIT parameter, MOR, helps identify effective lung recruitment maneuvers and detect overdistention in extremely preterm infants on HFOV, offering the potential to distinguish beneficial from harmful maneuvers.

IMPACT

We introduced a novel parameter, the median oscillations in aerated lung regions (MOR), derived from electrical impedance tomography (EIT), to evaluate oxygenation-guided lung recruitment in preterm infants on HFOV. The MOR parameter helps in identifying effective lung recruitment in terms of gas exchange and detecting overdistention, offering potential to differentiate beneficial from harmful lung recruitment maneuvers. This study presents a practical EIT-based parameter to evaluate lung recruitment and overdistention, providing a precise complement to conventional oxygenation metrics. The findings could optimize ventilation strategies in extremely preterm infants, potentially reducing lung injury and improving survival without bronchopulmonary dysplasia.