Fig. 1
Median (IQR) SpO2/FiO2 (Upper Panels) and Xrs (Lower Panels) vs. CDP. Left panels: CDP was normalized between 0% (CDPmin= minimal CDP) and 100% (CDPmax= maximal CDP). Parameters are computed for each 20% CDP change by linear interpolating the measured data. The grey and black lines represent the inflation and the deflation limbs, respectively. Right panels: values are averaged at initial CDP (CDPi), maximal CDP (CDPmax), CDP corresponding to maximal Xrs (CDPXrs), minimal CDP (CDPmin), optimal CDP as identified by SpO2 (CDPOpt_O2, grey circle). The figure reports the median [range] of Xrs and SpO2/FiO2 changes at selected CDPs. ΔXinf_limb = the difference in Xrs between CDPi and CDPmax, evaluating the impact of increasing CDP. The difference between CDPmax and CDPi was 10 [4–14] cmH2O and the Xrs change per cmH2O resulted: ΔXinf_limb/( CDPmax – CDPi ) = 1.5 [-7.3–14.1] s/L. ΔXcl = the difference in Xrs between CDPXrs and CDPmin to evaluate the impact of the lowest CDP applied. The difference between CDPXrs and CDPmin was 1 [0–10] cmH2O and the Xrs change per cmH2O resulted: ΔXcl/( CDPXrs - CDPmin) = 0.2 [0–16.4] s/L. ΔXrec = the difference in Xrs between CDPXrs during the inflation and the deflation limb to evaluate the hysteresis of the curve. It is reported as an absolute difference (cmH2O*s/L) and as a percentage of the value on the inflation limb. In 20 infants CDPXrs was lower than the CDPi, ΔXrec was computed at CDPi