Fig. 3

Dot plot of individual respiratory reactance (Xrs) (top panel) for the four groups: spontaneously breathing infants with no support (SB) and infants receiving NIV < 28 days (short-NIV) on the left (better respiratory outcome, BRO); infants receiving surfactant < 24 h (Surf < 24 h) and receiving surfactant after 24 h or NIV > 28 days (NIV-long or Surf > 24 h) on the right (worse respiratory outcome, WRO). The bottom panels show the area under the receiver operating characteristic curve (AUC-ROC) of Xrs for predicting WRO (bottom-left panel) and sensitivity and specificity of Xrs at different values (bottom- right panel). The best-identified cut-off of Xrs was − 23.3 cmH₂O*s/L