Figure 1
Characteristics of enrolled patients
| Overall | Mild ARDS | Moderate ARDS | Severe ARDS | |
|---|---|---|---|---|
| N (%) | 266 (100.0%) | 31 (11.7%) | 118 (44.4%) | 117 (44.0%) |
| Age (years), mean ± SD | 54.81 ± 18.66 | 48.84 ± 21.40 | 53.67 ± 18.64 | 57.54 ± 17.56 |
| Gender, n (%) | ||||
| Male | 153 (57.5%) | 16 (51.6%) | 66 (55.9%) | 71 (60.7%) |
| Female | 113 (42.5%) | 15 (48.4%) | 52 (44.1%) | 46 (39.3%) |
| BMI (kg/m2), mean ± SD | 22.21 ± 4.44 | 21.91 ± 3.59 | 21.96 ± 3.97 | 22.56 ± 5.11 |
| Etiology of ARDS (%) | ||||
| Pneumonia | 217 (81.6%) | 26 (83.9%) | 100 (84.7%) | 91 (77.8%) |
| Sepsis | 25 (9.4%) | 4 (12.9%) | 6 (5.1%) | 15 (12.8%) |
| HLH | 3 (1.1%) | 0 (0%) | 2 (1.7%) | 1 (0.9%) |
| Pneumonitis | 10 (3.8%) | 1 (3.2%) | 4 (3.4%) | 5 (4.3%) |
| Multiple factors | 6 (2.3%) | 0 (0%) | 5 (4.2%) | 1 (0.9%) |
| Unspecified cause | 2 (0.8%) | 0 (0%) | 1 (0.8%) | 1 (0.9%) |
| Diffuse alveolar hemorrhage | 3 (1.1%) | 0 (0%) | 0 (0%) | 3 (1.1%) |
| APACHE II median (25%, 75% quartile) | 26 (22, 31) | 23.16 (19, 27) | 25.09 (21, 29) | 27.69 (23, 32) |
| PaO2/FiO2, day 1, mean ± SD | 122.40 ± 58.64 | 237.88 ± 53.81 | 138.96 ± 28.08 | 75.29 ± 18.04 |
| Initial mode (%) | ||||
| PCV | 233 (87.6%) | 22 (71%) | 105 (89%) | 106 (90.6%) |
| VCV | 5 (1.9%) | 1 (3.2%) | 2 (1.7%) | 2 (1.7%) |
| PSV | 14 (5.3%) | 4 (12.9%) | 5 (4.2%) | 5 (4.3%) |
| SIMV | 2 (0.8%) | 1 (3.2%) | 1 (0.8%) | 0 (0%) |
| NIV | 7 (2.6%) | 2 (6.5%) | 1 (0.8%) | 4 (3.4%) |
| Bird mark 7 | 4 (1.5%) | 0 (0%) | 4 (3.4%) | 0 (0%) |
| Nasal high flow | 1 (0.4%) | 1 (3.2%) | 0 (0%) | 0 (0%) |
| Adjunctive interventions (%) | ||||
| APRV | 15 (5.6%) | 1 (3.2%) | 4 (3.4%) | 10 (8.5%) |
| HFOV | 4 (1.5%) | 0 (0%) | 3 (2.5%) | 1 (0.9%) |
| Prone | 10 (3.8%) | 0 (0%) | 5 (4.2%) | 5 (4.3%) |
| Recruitment maneuver | 128 (48.1%) | 10 (32.3%) | 58 (49.1%) | 60 (51.3%) |
| PIP in PCV, day 1, | 31 ± 6 | 27 ± 5 | 31 ± 6 | 32 ± 6 |
| mean ± SD (cm H2O) | ||||
| TV/kg IBW day 1, | 8.56 ± 2.48 | 8.71 ± 2.22 | 8.45 ± 2.56 | 8.64 ± 2.47 |
| mean ± SD (mL/kg IBW) | ||||
| PEEP, day 1, | 10 ± 4 | 7 ± 3 | 10 ± 4 | 12 ± 5 |
| mean ± SD (cm HO) 2 | ||||
| Neuromuscular blockade use (%) | 94 (35.3%) | 7 (22.6%) | 46 (39%) | 41 (35%) |
| Sedative drugs (%) | 229 (86.1%) | 25 (80.6%) | 102 (86.4%) | 102 (87.2%) |
| Morphine | 30 (11.3%) | 1 (3.2%) | 11 (9.3%) | 18 (15.4%) |
| Fentanyl | 194 (72.9%) | 22 (71.0%) | 86 (72.9%) | 86 (73.5%) |
| Midazolam | 197 (74.0%) | 20 (64.5%) | 87 (73.7%) | 90 (76.9%) |
| Propofol | 45 (16.9%) | 7 (22.3%) | 19 (16.1%) | 19 (16.2%) |
| I/O balance, day 1, | 2,484.94 ± 2,406.92 | 2,221.45 ± 2,202.28 | 2,161.26 ± 2,145.60 | 2,881.19 ± 2,694.55 |
| mean ± SD (mL/day) | ||||
| Total I/O balance in 3 days, | 5,029.31 ± 4,550 | 3,760 ± 3,370 | 4,370 ± 4,306 | 6,037 ± 4,892 |
| mean ± SD (mL/day) | ||||
| Total I/O balance in 7 days, | 6,634.97 ± 6,718.06 | 4,615.92 ± 6,327.18 | 5,771.69 ± 6,947.38 | 8,052.71 ± 6,337.84 |
| mean ± SD (mL/day) | ||||
| Enteral calories (kcal/day), AVG in | 673.75 ± 546.29 | 651.57 ± 590.71 | 724.63 ± 533.06 | 628.30 ± 547.78 |
| 7 days, mean ± SD | ||||
| Ventilator day (days), mean ± SD | 16.46 ± 20.11 | 24.77 ± 30.88 | 16.61 ± 17.38 | 14.11 ± 20.11 |
| Hospital LOS (days), mean ± SD | 27.1 ± 26.47 | 34.26 ± 33.60 | 29.63 ± 25.01 | 22.65 ± 25.26 |
| 7-day mortality, n (%) | 83 (31.1) | 4 (12.9) | 30 (25.4) | 49 (41.9) |
| 28-day mortality, n (%) | 184 (69.2) | 16 (51.6) | 82 (69.5) | 86 (73.5) |
Comparison of 28-day mortality of ARDS patients and factors possibly associated with mortality between our study and other studies including ALIEN, LUNG SAFE, PRoVENT, and APRONET
| Our study | ALIEN | LUNG SAFE | PRoVENT | APRONET | |
|---|---|---|---|---|---|
| [18] | [15] | [19] | [20] | ||
| Study period | 2010–2014 | 2008–2009 | 2014 | 2014–2015 | 2016–2017 |
| 28-day mortality | |||||
| All severity of ARDS | 69.2% | 42.7% | 34.8% | 29% | NA |
| Mild ARDS | 51.6% | NA | 29.6% | NA | NA |
| Moderate ARDS | 69.5% | NA | 35.2% | NA | NA |
| Severe ARDS | 73.5% | NA | 40.9% | NA | NA |
| Factors | |||||
| TV (mL/kg IBW) on day 1 | 8.56 ± 2.48 | 7.2 ± 1.1 | 7.6 | 7.6 | 6.7 |
| Percentage of patients with TV >8 mL/kg IBW on day 1 | 42.3% | NA | NA | 30% | NA |
| Percentage of Pplat measurement | 4% | 17.2% | 40% | 41% | 90.7% |
| Percentage of patients with prone position (in severe ARDS) | 4% | NA | 16% | NA | 32.9% |
| Percentage of patients receiving neuromuscular blockage | 35.3% | NA | 21.7% | NA | NA |
| Percentage of patients with recruitment maneuver | 48.1% | NA | 20.9% | NA | NA |
| Percentage of patients with ECMO | 0% | NA | 3.2% | NA | 1.9% |
| Percentage of patients with HFOV | 1.5% | NA | 1.2% | NA | NA |
| Percentage of patients with APRV | 5.63% | NA | NA | NA | NA |
Univariate analysis for 7- and 28-day mortalities
| Univariate analysis | 7-day mortality | 28-day mortality | ||||
|---|---|---|---|---|---|---|
| Crude HR | 95% CI | P | Crude HR | 95% CI | P | |
| Age (years) | 1.015 | 1.001–1.030 | 0.04 | 1.023 | 1.009–1.038 | <0.01* |
| Gender | ||||||
| Male (%) | 1 | 1 | ||||
| Female (%) | 0.742 | 0.436–1.262 | 0.27 | 0.789 | 0.468–1.333 | 0.38 |
| BMI | 0.994 | 0.930–1.063 | 0.87 | 0.967 | 0.906–1.031 | 0.31 |
| ARDS severity | ||||||
| Mild | 1 | 1 | ||||
| Moderate | 2.301 | 0.744–7.115 | 0.15 | 2.135 | 0.954–4.781 | 0.07 |
| Severe | 4.684 | 1.599–14.795 | <0.01* | 2.601 | 1.151–5.878 | 0.02* |
| APACHE II | 1.108 | 1.060–1.159 | <0.01* | 1.101 | 1.055–1.150 | <0.01* |
| PaO2/FiO2 ratio, day 1 | 0.992 | 0.987–0.997 | <0.01* | 0.997 | 0.993–1.001 | 0.18 |
| Mean PaO2/FiO2 ratio | 0.99 | 0.980–0.992 | <0.01* | 0.994 | 0.990–0.998 | <0.01* |
| TV/kg IBW, day 1 | 0.996 | 0.883–1.124 | 0.95 | 0.914 | 0.810–1.031 | 0.14 |
| Mean TV/kg IBW | 0.924 | 0.801–1.067 | 0.28 | 0.917 | 0.802–1.048 | 0.20 |
| PEEP, day 1 | 1.006 | 0.948–1.067 | 0.85 | 0.966 | 0.911–1.024 | 0.25 |
| Mean PEEP | 1.030 | 0.965–1.100 | 0.37 | 0.994 | 0.931–1.062 | 0.86 |
| PIP, day 1 | 1.061 | 1.004–1.121 | 0.04 | 1.040 | 0.983–1.101 | 0.17 |
| Recruitment maneuver | 0.910 | 0.542–1.529 | 0.77 | 1.312 | 0.778–2.211 | 0.31 |
| Pneumothorax | 0.478 | 0.226–1.008 | 0.05 | 1.079 | 0.553–2.104 | 0.82 |
| Neuromuscular blockade | 0.718 | 0.412–1.252 | 0.22 | 1.471 | 0.840–2.578 | 0.18 |
| I/O balance, day 1 (L/day) | 1.325 | 1.175–1.495 | <0.01* | 1.200 | 1.063–1.354 | <0.01* |
| Total I/O balance in 3 days (L/day) | 1.229 | 1.142–1.324 | <0.01* | 1.137 | 1.066–1.212 | <0.01* |
| Total I/O balance in 7 days (L/day) | 1.112 | 1.071–1.176 | <0.01* | 1.128 | 1.077–1.181 | <0.01* |
| 7-day AVG enteral calories (kcal/day) | 0.998 | 0.997–0.999 | <0.01* | 0.999 | 0.998–0.999 | <0.01* |
Multivariate analysis for 7- and 28-day mortalities
| Multivariate analysis | 7-day mortality† | 28-day mortality‡ | ||||
|---|---|---|---|---|---|---|
| Adjusted HR | 95% CI | P | Adjusted HR | 95% CI | P | |
| Age (years) | 1.004 | 0.985–1.023 | 0.70 | 1.002 | 0.979–1.027 | 0.63 |
| ARDS severity | ||||||
| Mild | 1 | 1 | ||||
| Moderate | 1.608 | 0.308–8.388 | 0.57 | 7.65 | 0.878–66.662 | 0.66 |
| Severe | 1.835 | 0.204–16.539 | 0.59 | 14.00 | 0.715–274.194 | 0.82 |
| APACHE II | 1.050 | 0.995–1.108 | 0.94 | 1.151 | 1.073–1.235 | <0.01* |
| PaO2/FiO2 ratio, day 1 | 1.003 | 0.995–1.011 | 0.50 | 1.003 | 0.994–1.013 | 0.46 |
| Mean PaO2/FiO2 ratio | 0.988 | 0.981–0.994 | <0.01* | 0.997 | 0.989–1.006 | 0.55 |
| TV/kg IBW, day 1 | 1.001 | 0.997–1.004 | 0.68 | |||
| PIP, day 1 | 1.037 | 0.966–1.114 | 0.32 | |||
| Neuromuscular blockade | 1.218 | 0.524–2.832 | 0.65 | |||
| I/O balance, day 1 | 0.984 | 0.818–1.182 | 0.86 | 0.816 | 0.666–0.998 | 0.048* |
| (L/day) | ||||||
| Total I/O balance in 3 days (L/day) | 1.192 | 1.102–1.289 | <0.01* | 0.969 | 0.802–1.169 | 0.74 |
| Total I/O balance in 7 days (L/day) | 1.061 | 0.979–1.150 | 0.15 | 1.103 | 1.026–1.186 | <0.01* |
| 7-day AVG enteral calories (kcal/day) | 0.998 | 0.997–0.999 | <0.01* | 0.999 | 0.998–1 | <0.01* |