Early Oscillatory Mechanics Predict Surfactant Need and Respiratory Outcomes in Preterm Infants

Abstract

Background: Current criteria for surfactant administration assume that hypoxia is a direct marker of lung-volume de-recruitment. Objectives: To evaluate whether lung reactance (Xrs) assessment by FOT within 2h of birth identifies infants who would need surfactant within 24h; to eventually determine Xrs performance and a cut-off value for early detection of infants requiring surfactant. Methods: We conducted a prospective, observational, non-randomized study in our tertiary NICU in Milan. Eligible infants were born between 27+0 and 34+6 weeks' gestation presenting respiratory distress after birth. Exclusion criteria: endotracheal intubation at birth, major malformations. We assessed Xrs during nasal CPAP at 5cmH2O at 10Hz within 2h of life, recording flow and pressure tracing through a Fabian Ventilator for off-line analysis. Clinicians were blinded to FOT results. Results: We enrolled 61 infants, with a median[IQR] gestational age of 31.9[30.3; 32.9]weeks and birth weight 1490[1230; 1816]g. 14/59 infants received surfactant within 24h. Xrs predicted surfactant need with a cut-off -33.4 cmH2O*s/L and AUC-ROC=0.86 (0.76-0.96), with sensitivity 0.85 and specificity 0.83. An Xrs cut-off value of -23.3 cmH2O*s/L identified infants needing surfactant or respiratory support >28 days with AUC-ROC=0.89 (0.81-0.97), sensitivity 0.86 and specificity 0.77. Interestingly, 12 infants with Xrs <-23.3 cmH2O*s/L (i.e. de-recruited lungs) did not receive surfactant and subsequently required prolonged respiratory support. Interpretation: Xrs assessed within 2 h of life predicts surfactant need and respiratory support duration in preterm infants. Xrs possible role for improving the individualization preterm infants' respiratory management deserves further investigation. Funding: None Declaration of Interest: RD reports grants and other from Restech, personal fees from Philips Healthcare, outside the submitted work; Dr Dellaca' has a patent on the detection of EFL by Forced Oscillation technique (FOT) with royalties paid to Philips Respironics and Restech Srl, a patent on monitoring lung volume recruitment by FOT with royalties paid to Vyaire, and a patent on early detection of exacerbations by home monitoring of FOT with royalties paid to Restech and is co-founder and shareholder of Restech Srl, a spin-off company of the Politecnico di Milano University producing medical devices for lung function testing based on FOT. AL was consultant for Getinge and Chiesi S.p.A and received travel grants from Vapotherm and Fischer&Pykel. The other authors have no financial interest to declare. Ethical Approval: Our ethical committee approved the research protocol in April 2016. Between December 2016 and February 2020, we recruited the study participants, whose follow-up lasted until discharge home.