Time to lung aeration during a sustained inflation at birth is influenced by gestation in lambs

Background Current sustained lung inflation (SI) approaches use uniform pressures and durations. We hypothesized that gestational-age-related mechanical and developmental differences would affect the time required to achieve optimal lung aeration, and resultant lung volumes, during SI delivery at birth in lambs. Methods 49 lambs, in five cohorts between 118 and 139 days of gestation (term 142 d), received a standardized 40 cmH 2 O SI, which was delivered until 10 s after lung volume stability (optimal aeration) was visualized on real-time electrical impedance tomography (EIT), or to a maximum duration of 180 s. Time to stable lung aeration ( T stable ) within the whole lung, gravity-dependent, and non-gravity-dependent regions, was determined from EIT recordings. Results T stable was inversely related to gestation ( P