The importance of lung recruitability: A novel ultrasound pattern to guide lung recruitment in neonates

Lung Ultrasound (LUS)-guided Lung Recruitment Maneuver (LRM) has been shown to possibly reduce ventilator-induced lung injury in preterm infants. However, to avoid potential hemodynamic and pulmonary side effects, the indication to perform the maneuver needs to be supported by early signs of lung recruitability. Recently, a new LUS pattern (S-pattern), obtained during the reopening of collapsed parenchyma, has been described. This study aims to evaluate if this novel LUS pattern is associated with a higher clinical impact of the LUS-guided LRMs.

All the LUS-guided rescue LRMs performed on infants with oxygen saturation/fraction of inspired oxygen (S/F) ratio below 200, were included in this cohort study. The primary outcome was to determine if the presence of the S-pattern is associated with the success of LUS-guided recruitment, in terms of the difference between the final and initial S/F ratio (Delta S/F).

We reported twenty-two LUS-guided recruitments, performed in nine patients with a median gestational age of 34 weeks, interquartile range (IQR) 28-35 weeks. The S-pattern could be obtained in 14 recruitments (64%) and appeared early during the procedure, after a median of 2 cmH2O (IQR 1-3) pressure increase. The presence of the S-pattern was significantly associated with the effectiveness of the maneuver as opposed to the cases in which the S-pattern could not be obtained (Delta S/F 110 +/- 47 vs 44 +/- 39, p = 0.01).

Our results suggest that the presence of the S-pattern may be an early sign of lung recruitability, predicting LUS-guided recruitment appropriateness and efficacy.