LAUSR

On 1 January 2018, about 380 000 babies were born in the world, half of them in India, China, Nigeria, Pakistan, Indonesia, USA, Democratic Republic of Congo, Ethiopia and Bangladesh.1 Considering that in a cohort of 5689 liveborn infants 8% received positive pressure ventilation at birth,2 around 8 million neonates globally would need respiratory support soon after birth each year. These high numbers come from term and moderate preterm infants born in low-income and middle-income countries, and from very and extreme preterm infants born in middle-income and high-income countries. In Norway, a cohort study of 1507 liveborn infants in three hospitals in 2011–2013 showed that 4%, 12%, 17% and 27% of infants at, respectively, ≥37, 34–36, 31–33 and <31 gestational weeks received positive pressure ventilation at birth.3 In the 20 centres of the Brazilian Network on Neonatal Research, among 2940 neonates born in 2014–2015 at 23–33 weeks’ gestational age, with birth weight of 400–1499 g, without malformations, 67% received positive pressure ventilation at birth.4 A study of the National Institute of Child Health and Human Development Neonatal Research Network, with data from 9565 newborns at gestational age less than 29 weeks born between 2003 and 2007, also showed that 67% received positive pressure ventilation at birth.5 In this context, knowledge on the most effective and safest ways to apply positive pressure ventilation soon after birth may impact on neonatal outcomes around the globe. To choose safe and effective devices and interfaces to apply positive pressure ventilation in newly born infants, it is important to understand the physiology of respiratory transition from the intrauterine to the extrauterine environment. The physiological mechanisms of the respiratory transition consist of three distinct and overlapping phases that occur in the …