Table 1.
Baseline (pre-randomization) characteristics comparisons
| Parameters | All patients n = 374 |
Not ready for weaning group (Recovery phase) n = 139 |
ZERO CPAP tolerance failure group (Weaning phase) n = 101 |
SBT failure Group (Weaning phase) n = 41 |
SNR Group (Recovery phase) n = 93 |
p value |
|---|---|---|---|---|---|---|
| Age, years | 63 ± 13 | 62 ± 13 | 63 ± 14 | 63 ± 13 | 65 ± 13 | 0.326 |
| Male – n (%) | 242 (65) | 95 (69) | 58 (59) | 30 (75) | 59 (65) | 0.212 |
| BMI, Kg/m2 – median [IQR] | 27.8 [24.2–32.1] | 28.9 [25.1–34.5] | 27.0 [23.5–30.2] | 25.9 [23.3–31.2] | 28.1 [24.9–32.0] | 0.010 |
| RASS | −1.37 ± 1.65 | −1.59 ± 1.78 | −1.44 ± 1.67 | −1.22 ± 1.60 | −1.01 ± 1.38 | 0.062 |
| Postoperative – n (%) | 74 (20) | 17 (12) | 19 (19) | 7 (17) | 31 (33) | 0.001 |
| Prognostic scores | ||||||
| Day 0 SOFA score | 6.50 ± 3.35 | 6.60 ± 3.19 | 5.73 ± 3.06 | 5.42 ± 2.70 | 7.55 ± 3.80 | < 0.001†§ |
| Charlson Comorbidity Index | 4.41 ± 3.13 | 4.11 ± 3.16 | 4.31 ± 2.87 | 5.24 ± 3.74 | 4.64 ± 3.02 | 0.216 |
| APACHE III score | 77 ± 30 | 83 ± 27 | 74 ± 28 | 71 ± 30 | 73 ± 35 | 0.023* |
| Mode of ventilation at enrollment | ||||||
| Pressure ACV – n (%) | 19 (5) | 10 (7) | 3 (3) | 0 (0) | 6 (7) | 0.189 |
| Volume ACV – n (%) | 22 (6) | 9 (7) | 8 (8) | 0 (0) | 5 (5) | 0.327 |
| PSV – n (%) | 325 (87) | 118 (85) | 88 (85) | 40 (98) | 79 (85) | 0.179 |
| Other (including PAV +) – n (%) | 10 (3) | 2 (1) | 4 (4) | 1 (2) | 3 (3) | 0.665 |
| First intubation to enrollment, days | 5.9 ± 5.0 | 6.6 ± 4.8 | 6.8 ± 5.9 | 5.2 ± 4.6 | 4.5 ± 4.1 | NA |
| Gas exchange | ||||||
| PaO2/FiO2 | 236 ± 81 | 218 ± 103 | 260 ± 101 | 242 ± 70 | 286 ± 102 | < 0.001* |
| PaCO2 | 41.2 ± 8.0 | 42.3 ± 8.1 | 41.1 ± 8.9 | 40.4 ± 6.7 | 39.8 ± 7.1 | 0.132 |
| Respiratory parameters | ||||||
| FiO2, % | 38 ± 8 | 43 ± 9 | 36 ± 6 | 37 ± 6 | 34 ± 6 | < 0.001* |
| Pressure support, cmH2O | 10.3 ± 3.4 | 11.1 ± 3.5 | 10.9 ± 3.2 | 9.7 ± 3.0 | 8.7 ± 2.9 | < 0.001*† |
| PEEP, cmH2O | 7.8 ± 2.5 | 9.7 ± 2.3 | 7.0 ± 1.7 | 6.6 ± 1.4 | 6.1 ± 1.6 | < 0.001*† |
| Vt, mL | 516 ± 155 | 547 ± 171 | 461 ± 130 | 514 ± 128 | 528 ± 151 | < 0.001† |
| RR, breaths/min | 20.9 ± 6.8 | 21.7 ± 7.2 | 23.1 ± 7.3 | 21.0 ± 6.1 | 17.4 ± 4.4 | < 0.001*†§ |
| VE, L/min | 10.3 ± 3.3 | 11.2 ± 3.3 | 10.1 ± 3.2 | 10.4 ± 3.2 | 9.0 ± 3.1 | < 0.001* |
Data presented as mean ± standard deviation unless otherwise stated
Pairwise comparisons between groups by Tukey Honest Significant Difference Test where p = 0.05 was taken as a threshold for these post-hoc comparisons:
ACV: assist control ventilation, APACHE: acute physiology and chronic health evaluation, BMI: body mass index, CPAP: continuous positive airway pressure, SNR: screened and non-randomized, FiO2: fraction of inspired oxygen, IQR: interquartile range, MV: mechanical ventilation, NA: not available, PAV + : proportional assist ventilation, PEEP: positive end-expiratory pressure, PSV: pressure support ventilation, RASS: Richmond agitation and sedation scale, RR: respiratory rate, SBT: spontaneous breathing trial, SOFA: sequential organ failure assessment, VE: minute ventilation, Vt: tidal volume
*Difference (p < 0.05) between Not ready for weaning group vs. SNR group
†Difference (p < 0.05) between ZERO CPAP tolerance failure group vs. SNR group
§Difference (p < 0.05) between SBT failure group vs. SNR group