Effects of sustained lung inflation (SLI) at birth on lung aeration during non-invasive resuscitation of preterm lambs

Background: SLI at birth has been shown to promote lung aeration in intubated preterm lambs (Tingay et al PedRes 2014). The effectiveness of applying SLI by full-face mask might be impaired by leaks, glottis closure, and accumulation of air in the stomach. Aim: To compare timing and magnitude of lung aeration at birth in preterm lambs receiving non-invasive resuscitation with and without the application of SLI. Methods: Preterm lambs (128d; ~28w in humans) were randomly assigned to receive SLI at birth (SLI group, n=7) or not (noSLI group, n=6). SLI group received two SLIs of 35s at 30cmH2O separated by 55s of nIPPV. All lambs received surfactant and were maintained with nIPPV (PEEP=8cmH2O, RR=60). PIP and FiO2 were adjusted to maintain PaCO2 at 35-55 mmHg and PaO2 at 60-80 mmHg up to 3h of life in both groups. Lung aeration was assessed as changes in lung reactance (Xrs) at 5Hz (Dellaca’ et al, ICM2011) measured by the forced oscillation technique. Data reported as median (IQR). Results: In both groups, Xrs increased with time (Figure). Xrs was significantly greater in SLI group at the end of each SLI and more variable in noSLI group. At 3h, Xrs stabilized at similar values for both groups. Conclusions: SLI applied non-invasively improved lung aeration and a more homogenous response in preterm lambs at birth. However, the improvements compared to CPAP disappear within few minutes.