Early postnatal respiratory dynamics in term and late preterm infants with respiratory distress

Information on lung volume characteristics in infants with clinical signs of respiratory distress immediately after birth is limited.

To assess changes in respiratory dynamics and physiological parameters in infants with and without respiratory distress in the delivery room and to determine the effect of continuous positive airway pressure (CPAP) support.

Electrical impedance tomography data were obtained from late preterm and term infants, born via caesarean section in a tertiary referral centre. Changes in the ratio of inspiratory to expiratory time (Ti/Te-ratio), end-expiratory lung impedance (∆EELI), oxygen saturation (SpO₂) and heart rate (HR) over the first 10 min as well as corresponding changes after CPAP application were assessed.

Of 73 infants, 18 (25%) received CPAP after birth (11 not admitted (CPAP group) and 7 admitted to the neonatal intensive care unit (CPAP/NICU)). Ti/Te ratio differed significantly between groups with the highest values in the CPAP/NICU group, mostly due to a reduced Te. There was no difference in ∆EELI. Similarly, infants in the CPAP/NICU group had lower SpO₂ and HR trajectories over time than the other two groups. After CPAP application, ΔEELI increased significantly. There were no changes in Ti/Te ratio, SpO₂ and HR after CPAP initiation.

In infants with more severe respiratory distress, Ti/Te ratio was increased, and SpO₂ and HR were reduced, suggesting that these parameters may serve as early predictors of respiratory failure. Application of CPAP resulted in an immediate increase in EELI, highlighting the importance of early CPAP initiation for infants with respiratory distress.