Variation of poorly ventilated lung units (silent spaces) measured by electrical impedance tomography to dynamically assess recruitment

Table 2 Lung mechanics, gas exchange, and hemodynamics data

Variable	PEEP 5 incremental phase	PEEP 10 incremental phase	PEEP 15	PEEP 10 decremental phase	PEEP 5 decremental phase	Friedman test p value
V_T, ml/kg IBW	7.4 [7.0–7.8]	7.5 [7.2–7.8]	7.6 [7.4–7.8]	7.6 [7.4–7.8]	7.6 [7.4–7.8]	0.171
RR, breaths/minute	15 [14–16]	16 [15–18]	16 [14–18]	16 [14–18]	15 [14–18]	0.275
MV, L/minute	6.4 [5.8–6.6]	6.9 [6.4–7.7]	6.8 [6.5–8.0]	6.8 [6.5–8.4]	6.8 [6.4–7.8]	0.222
Ppeak, cmH₂O	21 [19–28]	28 [26–30]^a	34 [32–35]^a,b	27 [25–30]^a,c	23 [21–28]^b,c,d	<0.001
Pplat, cmH₂O	15 [14–19]	21 [20–23]^a	26 [25–27]^a,b	20 [18–22]^a,b,c	15 [13–20]^b,c,d	< 0.001
Driving pressure, cmH₂O	10 [10–15]	11 [10–13]	12 [10–12]	10 [8–12]	10 [8–15]	0.100
Crs, ml/cmH₂O	39 [32–47]	38 [34–44]	38 [34–43]	43 [35–57]	45 [30–52]	0.100
PaCO₂, mmHg	53.8 [49.1–59.0]	53.3 [49.2–58.0]	54.0 [50.4–59.7]	52.2 [47.1–56.1]	51.8 [44.7–57.5]	0.246
PaO₂/FiO₂, mmHg	233 [159–286]	234 [163–279]	255 [178–292]	253 [203–320]	246 [172–304]	0.611
pH	7.33 [7.30–7.39]	7.34 [7.30–7.41]	7.32 [7.29–7.40]	7.34 [7.29–7.38]	7.34 [7.31–7.39]	0.170
MAP, mmHg	70 [66–85]	76 [67–83]	71 [64–76]	74 [66–80]	78 [70–82]	0.490
HR, beats/minute	76 [72–86]	76 [68–84]^a	72 [67–84]^a	73 [64–83]^a	77 [63–85]	0.021

Abbreviations: PEEP Positive end-expiratory pressure, RM Recruitment maneuver, V_T Tidal volume, IBW Ideal body weight, RR Respiratory rate, MV Minute ventilation, Ppeak Peak airway pressure, Pplat Plateau airway pressure, Crs Respiratory system compliance, PaCO₂ Partial pressure of carbon dioxide in arterial blood, PaO₂/FiO₂ Ratio of partial pressure of oxygen in arterial blood to fraction of inspired oxygen, MAP Mean arterial pressure, HR Heart rate
Data are expressed as median [IQR]
Wilcoxon post hoc test analysis for couples: ^aStatistically significant difference from PEEP 5 incremental phase; ^bStatistically significant difference from PEEP 10 incremental phase; ^cStatistically significant difference from PEEP 15; ^dStatistically significant difference from PEEP 10 decremental phase

ISSN: 1364-8535