Flow-controlled ventilation decreases mechanical power in postoperative ICU patients

Intensive Care Medicine Experimental

Table 3 EIT results PCV (baseline) vs optimized FCV (step 3); values represent median (IQR)

	Optimized FCV	p value
a. Changes in EIT parameters during FCV as compared to PCV^a
Global change in ΔZ (%)	59.4 (34.3–72.1)
Regional change in ΔZ (%)		0.030¹
ROI ventral	39.7 (22.1–49.5)
ROI mid-ventral	50.9 (26.6–66.3)
ROI mid-dorsal	73.6 (34.3–78.6)
ROI dorsal	81.1 (52.7–104.7)
Global change in static compliance (%)	13.4 (8.0–26.7)
Regional change in static compliance (%)		0.017²
ROI ventral	2.4 (− 7.0–19.2)
ROI mid-ventral	15.2 (2.7–24.2)
ROI mid-dorsal	23.3 (7.1–32.6)
ROI dorsal	27.5 (19.9–45.2)
Change in global EELI (a.u.)	53 (− 17–100)	0.163

	PCV	Optimized FCV	p value
b. Absolute EIT parameters reflecting lung and ventilation homogeneity
GI (%)	43.8 (41.4–45.3)	43.5 (39.7–45.7)	1.000
RVDi (%)	2.75 (2.28–4.63)	4.23 (3.39–6.11)	0.717

a.u. arbitrary units, EELI end-expiratory lung impedance, EIT electrical impedance tomography, FCV flow-controlled ventilation, GI global inhomogeneity index, PCV pressure-controlled ventilation, ROI region of interest, RVDi regional ventilation delay index
^aChanges in ΔZ and static compliance are expressed as percentage change between FCV step 3 and PCV at baseline, since both are expressed in arbitrary units which makes direct comparisons between patients unreliable
¹p value reflects the significant difference between PCV baseline vs. FCV step 3 regarding the distribution of ΔZ among the four ROIs, using a Kruskall Wallis test on the percentage changes from baseline (to account for the fact that ΔZ is measured in arbitrary units). ²p value reflects the significant difference between PCV baseline vs. FCV step 3 regarding the distribution of the change in static compliance among the four ROIs, using a Kruskall Wallis test on the percentage changes from baseline (to account for the fact that ΔZ and thereby also the static compliance is measured in arbitrary units)