Author, year | Success | Failure | P value | AUC |
Ventilation | ||||
Respiratory rate, RR (breaths per min) | ||||
Fox, 199320 | 81.4 (44.3–127) | 75.6 (43.3–91.8) | 0.52 | |
Smith, 199925 | 58 (12) | 60 (11) | NS | |
Vento, 200430 | 53 (28–67) | 43 (37–56) | 0.0129 | |
Davidson, 200832 | 53.4 (15.5) | 65 (17.8) | 0.054 | |
Dimitriou, 201137 | 74 (48–99) | 68 (52–80) | 0.224 | |
% of baseline RR after adding external dead space | ||||
Fox, 199320 | 99.4 (64.9–164) | 93 (65.8–113) | 0.281 | |
Tidal volume, Vt (mL/kg) | ||||
Veness-Meehan, 199014 | 5.1 (SE 0.3) | 6 (SE 0.5) | NS | |
Fox, 199320 | 5.32 (3–9.62) | 4.64 (3.24–13.4) | 0.7 | |
Smith, 199925 | 4.1 (1.4) | 3.7 (1) | NS | |
Kavvadia, 200028 | 5.8 (2–8.6) | 5.4 (3.1–8.7) | NS | 0.57 |
Kavvadia, 200028 | 5.8 (2–8.6) | 5.4 (3.1–8.7) | NS | 0.57 |
Vento, 200430 | 5.9 (4–7.8) | 5.9 (4.1–8.7) | 0.2512 | |
Kamlin, 200631 | 0.57 | |||
Davidson, 200832 | 5.3 (2.2) | 4.9 (3.1) | 0.563 | |
Dimitriou, 201137 | 3.2 (2–9) | 2.8 (2–4.2) | 0.512 | |
Kaczmarek, 201341 | 4.5 (1.8) | 4.21 (1.2) | NS | |
% of baseline Vt after adding external dead space | ||||
Fox, 199320 | 162 (79.3–221) | 140 (68.5–206) | 0.136 | |
Spontaneous minute ventilation, MVs (mL/kg/min) | ||||
Veness-Meehan, 199014 | 341 (SE 18) | 370 (SE 34) | NS | |
Fox, 199320 | 383 (134–1090) | 353 (186–784) | 0.31 | |
Vento, 200430 | 309 (223–434) | 240 (160–353) | 0.0039 | |
Kamlin, 200631 | 314 (116) | 271 (113) | NS | 0.6 |
Chawla, 2013 (L/min)40 | 0.26 (0.11) | 0.27 (0.18) | 0.86 | |
% of baseline MVs after adding external dead space | ||||
Fox, 199320 | 156 (89.3–230) | 131 (75.2–165) | 0.006 | |
% time spent with MVs below 125 mL/kg/min | ||||
Vento, 200430 | 1.3 (0–12.9) | 13.6 (8.2–45.4) | <0.0001 | 0.94 |
Minute ventilation ratio, MVs/MVm | ||||
Kamlin, 200633 | 0.74 | |||
Chawla, 201340 | 0.81 (0.24) | 0.53 (0.29) | <0.01 | |
Rapid shallow breathing index, RR/Vt (breaths/min/mL/kg) | ||||
Smith, 199925 | 13.6 (6.7) | 14.8 (4.1) | NS | |
Davidson, 200832 | 16.5 (7.4) | 21.3 (7.8) | 0.074 | |
Dimitriou, 201137 | 21.9 (7.7–48.9) | 22.2 (15.4–29.3) | 0.896 | |
Breathing pattern | ||||
Inspiratory time, Ti (s) | ||||
Smith, 199925 | 0.36 (0.11) | 0.39 (0.09) | NS | |
Kaczmarek, 201341 | 0.43 (0.2) | 0.39 (0.12) | NS | |
Expiratory time, Te (s) | ||||
Kaczmarek, 201341 | 0.58 (0.22) | 0.53 (0.13) | NS | |
Ratio of Ti over total respiratory cycle time, Ti/Ttot | ||||
Currie, 201136 | 0.33 (0.2–0.49) | 0.34 (0.31–0.42) | 0.513 | |
Dimitriou, 201137 | 0.39 (0.29–0.49) | 0.367 (0.34–0.44) | 0.694 | |
Kaczmarek, 201341 | 0.44 (0.08) | 0.46 (0.08) | NS | |
Mean inspiratory flow, Vt/Ti (mL/kg/s) | ||||
Veness-Meehan, 199014 | 13.8 (SE 2.8) | 14 (SE 1.3) | NS | |
Smith, 199925 | 12 (7.3) | 12.5 (3.1) | NS | |
Kaczmarek, 201341 | 14.2 (8) | 11.2 (4.1) | NS | |
Lung mechanics | ||||
Compliance, C (mL/cmH2O/kg) | ||||
Veness-Meehan, 199014 | 1 (SE 0.1) | 1.1 (SE 0.2) | NS | |
Higgins, 199115 | 1.2 | 1.3 | NS | |
Kavvadia, 200028 | 0.94 (0.31–1.54) | 0.74 (0.42–1.05) | NS | 0.57 |
Dimitriou, 200245 | 0.77 (0.32–2.18) | 0.79 (0.43–1.16) | NS | 0.54 |
Vento, 200430 | 1.2 (0.52–1.9) | 0.95 (0.62–1.5) | 0.09 | |
Resistance, R (cmH2O/L/s) | ||||
Veness-Meehan, 199014 | 37.4 (SE 3.8) | 43.6 (SE 5.8) | NS | |
Higgins, 199115 | 56.2 | 37.1 | NS | |
Vento, 200430 | 70 (27–125) | 69 (49–164) | 0.4 | |
Work of breathing (g × cm/kg) | ||||
Veness-Meehan, 199014 | 10.4 (SE 1.6) | 15.1 (SE 3.9) | NS | |
Higgins, 199115 | 7.7 | 8.6 | NS | |
Respiratory muscle function | ||||
Mean inspiratory pressure (cmH2O) | ||||
Dimitriou, 200245 | 16.7 (6.6–57.2) | 11.3 (7.3–19.7) | <0.03 | 0.78 |
Currie, 201136 | 6.3 (3.3–11.8) | 10.6 (9.1–13.6) | 0.013 | |
Mean inspiratory pressure adjusted to weight (cmH2O/kg) | ||||
Dimitriou, 200245 | NS | 0.59 | ||
Maximum inspiratory pressure, MIP (cmH2O) | ||||
Chen, 199216 | 42.6 (7.2) | 21.2 (1.8) | <0.01 | |
Sillos, 199217 | 33.8 (12.3) | 23.3 (15) | <0.005 | |
Dimitriou, 200245 | 24.8 (14.1–69.3) | 14.3 (9.9–21.2) | <0.01 | 0.9 |
Currie, 201136 | 45.5 (29.4–83) | 19 (17–30.3) | 0.002 | |
Bhat, 201644 | 46 (15–79) | 37 (9–88) | 0.42 | 0.57 |
MIP adjusted to weight (cmH2O/kg) | ||||
Dimitriou, 200245 | NS | 0.52 | ||
Currie, 201136 | 29.1 (9.9–50.6) | 22.1 (8–29.4) | 0.074 | |
Maximum expiratory pressure (cmH2O) | ||||
Bhat, 201644 | 35 (6–81) | 27 (15–42) | 0.17 | 0.66 |
Ratio of mean inspiratory pressure/MIP | ||||
Currie, 201136 | 0.12 (0.04–0.32) | 0.56 (0.45–0.68) | 0.001 | |
Respiratory drive (cmH2O) | ||||
Currie, 201136 | 4.4 (2–7.7) | 6.3 (4.8–7.1) | 0.126 | |
Bhat, 201644 | 8 (2.8–17.7) | 9.7 (1.7–18.7) | 0.39 | 0.59 |
Mean diaphragmatic pressure (cmH2O) | ||||
Currie, 201136 | 7.8 (3.7–19.9) | 8.5 (7.7–12.6) | 0.275 | |
Dimitriou, 201137 | 8.9 (5.2–15.6) | 13.7 (11.2–16.7) | 0.03 | |
Maximum diaphragmatic pressure (cmH2O) | ||||
Currie, 201136 | 48.2 (30.1–83) | 17.9 (17–33.1) | 0.002 | |
Bhat, 201644 | 56.5 (30–305) | 48.8 (28.4–88.7) | 0.13 | 0.68 |
Maximum diaphragmatic pressure adjusted to weight (cmH2O/kg) | ||||
Currie, 201136 | 29.7 (9.9–51.9) | 22.1 (8–26.7) | 0.067 | |
Ratio of mean/maximum diaphragmatic pressure | ||||
Currie, 201136 | 0.17 (0.07–0.29) | 0.48 (0.38–0.65) | 0.001 | |
Dimitriou, 201137 | 0.2 (0.09–0.34) | 0.4 (0.28–0.49) | 0.003 | |
Transdiaphragmatic pressure–time product (cmH2O/s/min) | ||||
Dimitriou, 201137 | 200 (101–417) | 268 (170–332) | 0.358 | |
Tension time index of the diaphragm | ||||
Currie, 201136 | 0.065 (0.02–0.12) | 0.16 (0.15–0.2) | 0.001 | 1 |
Dimitriou, 201137 | 0.079 (0.03–0.12) | 0.142 (0.12–0.18) | 0.002 | |
Bhat, 201644 | 0.04 (0.02–0.14) | 0.16 (0.03–0.79) | <0.001 | 0.89 |
Tension time index of respiratory muscles | ||||
Currie, 201136 | 0.04 (0.01–0.13) | 0.19 (0.19–0.21) | 0.001 | 1 |
Dimitriou, 201137 | 0.079 (0.04–0.12) | 0.145 (0.13–0.17) | 0.002 | |
Bhat, 201644 | 0.07 (0.03–0.17) | 0.19 (0.08–1.39) | 0.003 | 0.82 |
Vital signs | ||||
Fraction of inspired oxygen | ||||
Vento, 200430 | 0.23 (0.21–0.28) | 0.25 (0.22–0.3) | 0.0175 | |
Robles-Rubio, 201543 | 0.26 (0.07) | 0.32 (0.23) | <0.05 | |
Heart rate, beats per min | ||||
Smith, 199925 | 145 (13) | 149 (12) | NS | |
Oxygen saturation, % | ||||
Smith, 199925 | 92 (2.5) | 92 (3.6) | NS | |
Vento, 200430 | 95 (88–98) | 91 (88–95) | 0.0004 | 0.75 |
Robles-Rubio, 201543 | 94 (4) | 94 (3) | NS | |
Transcutaneous oxygen pressure, mm Hg | ||||
Vento, 200430 | 72 (59–95) | 60 (55–85) | 0.0031 | 0.8 |
Transcutaneous carbon dioxide pressure, mm Hg | ||||
Vento, 200430 | 44 (37–52) | 52 (46–55) | <0.0001 | 0.63 |
Data are presented as mean (SD) or median (IQR).
AUC, area under the curve; NS, non-significant.