Distribution of lung ventilation in spontaneously breathing neonates lying in different body positions

Objective: The aim of our study was to determine the effect of the irregular spontaneous breathing pattern and posture on the spatial distribution of ventilation in neonates free from respiratory disease by the non-invasive imaging method of electrical impedance tomography (EIT). Scanning of spontaneously breathing neonates is the prerequisite for later routine application of EIT in babies with lung pathology undergoing ventilator therapy. Design: Prospective study. Setting: Neonatal intensive care unit at a university hospital. Patients: Twelve pre-term and term neonates (mean age: 23 days; mean body weight: 2,465 g; mean gestational age: 34 weeks; mean birth weight: 2,040 g). Interventions: Change in body position in the sequence: supine, right lateral, prone, supine. Measurements and results: EIT measurements were performed using the Gottingen GoeMF I system. EIT scans of regional lung ventilation showing the distribution of respired air in the chest cross-section were generated during phases of rapid tidal breathing and deep breaths. During tidal breathing, 54.5+/-8.3%, 55.2+/-10.5%, 59.9+/-8.4% and 54.2+/-8.5% of inspired air (mean values +/- SD) were directed into the right lung in the supine, right lateral, prone and repeated supine postures respectively. During deep inspirations, the right lung ventilation accounted for 52.6+/-7.9%, 68.5+/-8.5%, 55.4+/-8.2% and 50.5+/-6.6% of total ventilation respectively. Conclusion: The study identified the significant effect of breathing pattern and posture on the spatial distribution of lung ventilation in spontaneously breathing neonates. The results demonstrate that changes in regional ventilation can easily be determined by EIT and bode well for the future use of this method in paediatric intensive care.