Table 2 Main results of the study
From: Physiological effects of awake prone position in acute hypoxemic respiratory failure
| Â | Supine position | Prone position | Supine position after proning | P value1 Supine versus prone | P value2 Prone versus supine position after proning | P value3 Supine versus supine position after proning |
|---|---|---|---|---|---|---|
Gas exchange | Â | Â | Â | Â | Â | Â |
FiO2 | 0.6 [0.6–0.6] | 0.6 [0.6–0.6] | 0.6 [0.6–0.6] |  > 0.99 |  > 0.99 |  > 0.99 |
PaO2, mmHg | 74 [69–93] | 104 [76–129] | 66 [54–73] | 0.001 | 0.02 |  > 0.001 |
PaO2/FiO2, mmHg | 123 [111–155] | 191 [125–217] | 110 [90–124] | 0.002 |  < 0.001 | 0.001 |
SpO2, % | 97 [96–99] | 97 [96–99] | 94 [90–95] |  > 0.99 |  < 0.001 | 0.002 |
PaCO2, mmHg | 35 [32–36] | 34 [33–37] | 35 [33–38] | 0.71 |  > 0.99 |  > 0.99 |
Self-assessed symptoms | Â | Â | Â | Â | Â | Â |
Dyspnea, VAS | 4 [2–4] | 3 [1–4] | 3 [1–4] | 0.11 | 0.71 |  > 0.99 |
Self-assessed discomfort, VAS | 3 [2–5] | 5 [4–6] | 3 [2–4] | 0.14 | 0.01 |  > 0.99 |
Respiratory mechanics | Â | Â | Â | Â | Â | Â |
Esophageal pressure, end expiratory, cmH2O | 7 [7–13] | 6 [3–7] | 7 [6–14] |  < 0.001 |  > 0.99 |  < 0.001 |
Transpulmonary pressure, end expiratorya, cmH2O | − 5 [− 11 to − 4] | − 4 [− 5 to 0] | − 5 [− 11 to − 3.5] |  < 0.001 |  < 0.001 |  > 0.99 |
ΔPES, cmH2O | 9 [8–12] | 12 [11–13] | 9 [8–14] | 0.04 | 0.43 |  > 0.99 |
ΔPL, cmH2O | 8 [5–9] | 9 [7–11] | 7 [6–9] | 0.17 | 0.51 |  > 0.99 |
Inspiratory time, s | 1.05 [0.90–1.32] | 0.95 [0.90–1.20] | 1.00 [0.77–1.25] |  > 0.99 |  > 0.99 |  > 0.99 |
Expiratory time, s | 1.23 [0.96–1.41] | 1.44 [1.38–1.49] | 1.31[1.15–1.57] | 0.05 | 0.43 |  > 0.99 |
Respiratory rate, breaths per minute | 27 [26–30] | 24 [22–26] | 27 [23–34] | 0.05 | 0.03 |  > 0.99 |
Simplified PES pressure–time-product per minute, cmH2O s min−1 | 105 [81–129] | 131 [75–154] | 117 [57–184] |  > 0.99 |  > 0.99 |  > 0.99 |
Time constant (s) | 0.40 [0.37–0.44] | 0.53 [0.32–0.61] | 0.41 [0.31–0.46] | 0.03 | 0.05 |  > 0.99 |
Resistance (cmH2O s A.U.−3) | 6 [3–9] | 9 [4–11] | 7 [2–10] | 0.05 | 0.13 |  > 0.99 |
EIT-derived indices | Â | Â | Â | Â | Â | Â |
Standardized minute ventilation (arbitrary unites/minute) | 11524 [8959–26376] | 15927 [14673–20894] | 15522 [9062–34072] | 0.09 |  > 0.99 | 0.30 |
TidalΔZ, arbitrary units | 528 [418–1004] | 756[669–1275] | 643[401–1244] | 0.08 | 0.08 |  > 0.99 |
Ventral ROI | 27 [12–65] | 61 [16–80] | 42 [29–53] | 0.01 |  > 0.99 | 0.13 |
Mid-ventral ROI | 78 [50–233] | 102 [55–397] | 171 [32–303] |  > 0.99 |  > 0.99 |  > 0.99 |
Mid-dorsal ROI | 200 [164–566] | 279 [255–580] | 253 [145–499] | 0.09 |  > 0.99 | 0.09 |
Dorsal ROI | 54 [37–184] | 122 [87–225] | 87 [35–213] | 0.05 |  > 0.99 | 0.43 |
Pendelluft, % of TidalΔZ | 31 [14–55] | 55 [7–57] | 44 [13–66] |  > 0.99 | 0.30 | 0.82 |
Lung Compliance, Arbitrary units/cmH2O | 67 [60–115] | 89 [79–179] | 76 [57–162] |  > 0.99 |  > 0.99 |  > 0.99 |
Ventral ROI | 2 [2–9] | 7 [2–10] | 5 [4–7] | 0.13 | 0.60 |  > 0.99 |
Mid-ventral ROI | 12 [7–21] | 10 [7–35] | 20 [7–43] |  > 0.99 |  > 0.99 |  > 0.99 |
Mid-dorsal ROI | 28 [20–67] | 38 [26–81] | 23 [17–80] |  > 0.99 |  > 0.99 |  > 0.99 |
Dorsal ROI | 7 [5–21] | 16 [10–22] | 10 [7–26] | 0.13 | 0.60 |  > 0.99 |
EELI, arbitrary units | 1456 [959–2420] | 3887 [3414–8547] | 1879 [1114–4143] | 0.002 | 0.01 |  > 0.99 |
Ventral ROI | 73 [49–105] | 265 [111–390] | 106 [43–198] |  < 0.001 | 0.02 |  > 0.99 |
Mid-ventral ROI | 492 [293–786] | 1195 [1061–2372] | 573 [371–1187] | 0.002 | 0.01 |  > 0.99 |
Mid-dorsal ROI | 736 [440–1288] | 1794 [1656–4325] | 849 [550–2029] |  < 0.001 | 0.004 |  > 0.99 |
Dorsal ROI | 194 [129–340] | 615 [494–1015] | 299 [131–583] | 0.002 | 0.01 |  > 0.99 |
Dynamic strain | 0.38 [0.30–0.59] | 0.21 [0.16–0.24] | 0.27 [0.22–0.55] | 0.004 | 0.04 |  > 0.99 |
Ventral ROI | 0.35 [0.23–0.58] | 0.23 [0.12–0.29] | 0.34 [0.28–0.77] | 0.04 | 0.02 |  > 0.99 |
Mid-ventral ROI | 0.20 [0.12–0.32] | 0.07 [0.04—0.15] | 0.19 [0.08—0.43] | 0.01 | 0.14 |  > 0.99 |
Mid-dorsal ROI | 0.34 [0.21–0.50] | 0.16 [0.10–0.24] | 0.23 [0.19–0.31] |  < 0.001 | 0.11 | 0.39 |
Dorsal ROI | 0.32 [0.24–0.42] | 0.17 [0.15–0.25] | 0.31 [0.15–0.54] | 0.27 |  > 0.99 | 0.77 |
Hemodynamics | Â | Â | Â | Â | Â | Â |
Heart rate, beats per minute | 72 [62–80] | 74 [65–78] | 75 [61–84] | 0.72 | 0.13 | 0.55 |
Arterial pressure, mmHg | Â | Â | Â | Â | Â | Â |
Systolic | 138 [120–151] | 136 [122–155] | 132 [112–149] | 0.44 | 0.45 | 0.86 |
Diastolic | 72 [58–90] | 70 [58–81] | 66 [55–87] | 0.32 | 0.45 | 0.12 |