Abstract
OBJECTIVE: To assess lung aeration changes during clinically directed transitions from CPAP to HFNC in preterm infants using Electrical Impedance Tomography (EIT). DESIGN: Prospective, observational study. SETTING: Single-center, Level IV Neonatal Intensive Care Unit. PATIENTS: Infants born < 32 weeks gestational age (GA) undergoing a clinically indicated transition from CPAP to HFNC following ≥ 2 weeks of respiratory support. INTERVENTIONS: EIT data were recorded for 30-60 min before and after transition. MAIN OUTCOME MEASURES: The primary outcome was change in end-expiratory lung impedance (ΔEELI). Infants were followed for 7 days following transition to assess for transition failure. RESULTS: From 15 subjects, 4257 total breaths were analyzed. No significant difference in %∆EELI was found between HFNC and CPAP (Median ∆: -1.0%; IQR -3.6% to 6.0%; p = 0.78). The largest %∆EELI decrease (-9.8%) occurred in the subject who failed transition. CONCLUSIONS: Transitioning from CPAP to HFNC did not consistently decrease lung aeration in stable preterm infants. In the infant who failed transition, a distinct respiratory pattern was observed using EIT, characterized by a decrease in EELI and frequent recruitment breaths. These findings suggest better methods are needed to individualize and titrate respiratory support at the bedside for preterm infants.