Background and aims Lung ultrasound (LUS) has been recently proposed to obtain fast and reproducible informations in critical care and to diagnose respiratory distress syndrome, wet lung or air leaks. Nevertheless, no data are available about its use for monitoring lung function and eventually guide respiratory support. We investigate the use of LUS score to estimate oxygenation status and surfactant need in neonates.

Methods 55 consecutive neonates under CPAP underwent LUS with a 7.5 MHz microconvex probe both on transversal and longitudinal scan. Three lung areas (upper, lower, lateral) were examined according to a score previously published in critically ill adults and modified for neonates.[1] Such score is based on prevalence of A-lines, <3 B-lines, >3 crowded B-lines or consolidation (0–3 points, respectively). Transcutaneous PaO₂ and PaCO₂, FiO₂, airway pressure were recorded during LUS. PaO₂/FiO₂, oxygenation index and A-a gradient were calculated.

Results Mean GA and BW were 33 (SD 3.2) wks and 2310 (SD 893) g, respectively. LUS score is highly correlated with PaO₂/FiO₂ (rho = -0.77; p < 0.001), oxygenation index (rho = 0.79; p < 0.001) and A-a gradient (rho = 0.78; p < 0.001). These correlations remained significant after adjustment for birth weight, gestational and postnatal age. LUS score shows high reliability for surfactant need (AUC = 0.82; p = 0.005; best cut off 11.5 [sensitivity 75%, specificity 90%]).

Conclusions LUS score is well correlated with oxygenation status and shows enough relibiality to predict surfactant need. LUS can be used to monitor serially the course of respiratory conditions in critically ill neonates.

Reference

1. Via G, Lung ultrasound in the ICU: from diagnostic instrument to respiratory monitoring tool. Minerva Anestesiol 2012;78:1282–96