RT Journal Article SR Electronic T1 Laryngeal closure impedes non-invasive ventilation at birth JF Archives of Disease in Childhood - Fetal and Neonatal Edition JO Arch Dis Child Fetal Neonatal Ed FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health SP fetalneonatal-2017-312681 DO 10.1136/archdischild-2017-312681 A1 Jessica R Crawshaw A1 Marcus J Kitchen A1 Corinna Binder-Heschl A1 Marta Thio A1 Megan J Wallace A1 Lauren T Kerr A1 Charles C Roehr A1 Katie L Lee A1 Genevieve A Buckley A1 Peter G Davis A1 Andreas Flemmer A1 Arjan B te Pas A1 Stuart B Hooper YR 2017 UL http://fn.bmj.com/content/early/2017/10/20/archdischild-2017-312681.abstract AB Background Non-invasive ventilation is sometimes unable to provide the respiratory needs of very premature infants in the delivery room. While airway obstruction is thought to be the main problem, the site of obstruction is unknown. We investigated whether closure of the larynx and epiglottis is a major site of airway obstruction.Methods We used phase contrast X-ray imaging to visualise laryngeal function in spontaneously breathing premature rabbits immediately after birth and at approximately 1 hour after birth. Non-invasive respiratory support was applied via a facemask and images were analysed to determine the percentage of the time the glottis and the epiglottis were open.Hypothesis Immediately after birth, the larynx is predominantly closed, only opening briefly during a breath, making non-invasive intermittent positive pressure ventilation (iPPV) ineffective, whereas after lung aeration, the larynx is predominantly open allowing non-invasive iPPV to ventilate the lung.Results The larynx and epiglottis were predominantly closed (open 25.5%±1.1% and 17.1%±1.6% of the time, respectively) in pups with unaerated lungs and unstable breathing patterns immediately after birth. In contrast, the larynx and the epiglottis were mostly open (90.5%±1.9% and 72.3%±2.3% of the time, respectively) in pups with aerated lungs and stable breathing patterns irrespective of time after birth.Conclusion Laryngeal closure impedes non-invasive iPPV at birth and may reduce the effectiveness of non-invasive respiratory support in premature infants immediately after birth.