Regional Differences in Lung Ventilation During the Early Transition Period in Late Preterm and Term Neonates Assessed by Electrical Impedance Tomography.

Background: Changes in lung ventilation are well documented in term neonates while in late preterm neonates these patterns are poorly understood despite their increased risk of respiratory morbidity.

Objectives: The study aimed to compare and clarify the differences in regional lung ventilation of late preterm and term neonates during the early adaptation period using electrical impedance tomography (EIT).

Material And Methods: The case-control study was conducted in the years 2020-2022. It included 51 late preterm neonates (LPN, Study group) and 45 term neonates (TN, Control) born by normal vaginal delivery (NVD). EIT examinations were performed with a Swisstom BB2 (Switzerland) equipment. The data recordings were performed no later than 30 (I Record), 60 (II), and 90 (III) minutes after the birth.

Results: Statistically significant differences between LPN and TN were observed in the non-dependent lung areas at I record, with more silent spaces observed in the LPN ( < 0.001). Differences in the dependent lung regions were observed across all recordings, with LPN demonstrating more silent spaces ( < 0.001). LPN demonstrated greater stretch-related changes in the 10% and 20% stretch categories across all recordings, while TN showed greater changes in the 50%, 70%, and 90% categories. Tidal volumes in the right lung of TN are distributed more towards the ventral and central ventral regions. In contrast, tidal volumes of LPN are distributed to the central dorsal and dorsal regions of the right lung.

Conclusions: LPN during the first 90 min after the birth show reduced lung ventilation assessed by EIT, suggesting a possible impairment of early postnatal adaptation.