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Table 1 Patient characteristics, outcomes, and ventilation characteristics

From: The predictive validity for mortality of the driving pressure and the mechanical power of ventilation

Characteristics All Survivors Non–survivors P value
N = 839 N = 489 N = 350
Age (years) 61 [50 to 70] 58 [47 to 68] 63 [53 to 73] < 0.001
Gender (male) 555 (66%) 314 (64%) 241 (69%) 0.23
Ethnicity, no. (%) 0.09
 African 12 (1%) 5 (1%) 7 (2%)
 Asian 9 (1%) 4 (1%) 5 (1%)
 Caucasian 733 (87%) 428 (88%) 305 (87%)
 Latin American 16 (2%) 8 (2%) 8 (2%)
 Other 69 (8%) 44 (9%) 25 (7%)
BMI (kg/m2) 25 [23 to 29] 25 [23 to 29] 25 [23 to 28] 0.61
PBW (kg) 71 [62 to 75] 71 [62 to 75] 71 [62 to 75] 0.66
ARDS, N (%) 223 (22%) 130 (21%) 93 (22%) 0.96
 Mild 118 (14%) 67 (14%) 51 (14%)  
 Moderate 97 (12%) 60 (13%) 37 (10%)  
 Severe 8 (1%) 3 (1%) 5 (1%)  
Reason for ICU admission, no. (%) 0.25
 Planned surgery 116 (14%) 75 (15%) 41 (12%)
 Emergency surgery 207 (25%) 122 (25%) 85 (24%)
 Medical 513 (61%) 289 (59%) 224 (64%)
Risk of death (%)a 32 [14 to 59] 23 [10 to 47] 48 [23 to 74] < 0.001
Reason for intubation, no. (%) 0.06
 Cardiac arrest 134 (16%) 58 (12%) 76 (22%)
 Post–surgery 207 (25%) 130 (27%) 77 (22%)
 Depressed level of consciousness 77 (9%) 45 (9%) 32 (9%)
 Respiratory failure 312 (37%) 187 (38%) 125 (36%)
 Other 109 (13%) 69 (14%) 40 (11%)
Chronic comorbidity, no. (%)
 Hypertension 231 (28%) 137 (28%) 94 (27%) 0.73
 Diabetes mellitus 127 (15%) 69 (14%) 58 (17%) 0.40
 Heart failure 69 (8%) 44 (9%) 25 (5%) 0.39
 Chronic kidney failure 60 (7%) 19 (4%) 41 (12%) < 0.001
 Cirrhosis 9 (1%) 1 (0%) 8 (2%) 0.01
 COPD 89 (11%) 43 (9%) 46 (13%) 0.06
 Oxygen at home 5 (1%) 2 (0%) 3 (1%) 0.72
 Cancer 46 (5%) 19 (4%) 27 (8%) 0.43
 Immunodeficiency 88 (10%) 47 (10%) 41 (12%) 0.40
 Ventilation at home 10 (1%) 6 (1%) 4 (1%) 1.00
Vital signs
 SpO2 (%) 98 [96 to 100] 98 [96 to 100] 98 [96 to 100] 0.79
 Heart rate (bpm) 101 [83 to 120] 100 [83 to 118] 102 [83 to 121] 0.39
 MAP (mm Hg) 57 [52 to 62] 58 [53 to 63] 56 [50 to 60] < 0.001
 Temperature (C) 36.7 [35.9 to 37.3] 36.8 [36.0 to 37.4] 36.6 [35.7 to 37.2] 0.03
Severity of illness, SOFA score
 Total 5 [4 to 8] 4 [3 to 7] 6 [4 to 9] < 0.001
 Non–pulmonary SOFA 4 [4 to 7] 4 [3 to 6] 5 [4 to 8] < 0.001
 Pulmonary 0 [0 to 1] 0 [0 to 1] 0 [0 to 1] 0.07
 Hematologic 0 [0 to 1] 0 [0 to 1] 0 [0 to 2] 0.12
 Liver 0 [0 to 0] 0 [0 to 0] 0 [0 to 0] 0.12
 Circulation 4 [3 to 4] 3 [2 to 4] 4 [3 to 4] < 0.001
 Neurology 0 [0 to 1] 0 [0 to 1] 0 [0 to 3] 0.01
 Renal 0 [0 to 0] 0 [0 to 0] 0 [0 to 1] < 0.001
Outcomes
 ICU mortality, no. (%) 220 (26%) 0 (0%) 220 (63%) < 0.001
 Hospital mortality, no. (%) 305 (36%) 3 (1%) 301 (86%) < 0.001
 ICU LOS, days 7 [4 to 12] 7 [4 to 13] 7 [4 to 12] 0.12
 Hospital LOS, days 22 [11 to 42] 31 [17 to 50] 13 [6 to 27] < 0.001
 Duration of mechanical ventilation, days 5 [3 to 10] 5 [3 to 10] 6 [3 to 10] 0.60
 VFD–28, days 17 [0 to 24] 23 [18 to 25] 0 [0 to 0] < 0.001
Ventilatory variables, median [IQR]
 Tidal volume (ml) 471 [410 to 540] 476 [ 417 to 546] 461 [405 to 531] 0.04
 Tidal volume (ml/kg PBW) 6.8 [6.0 to 8.0] 6.9 [6.1 to 7.9] 6.8 [5.8 to 7.9] 0.09
 Respiratory rate (bpm) 20 [16 to 26] 20 [15 to 25] 22 [17 to 28] 0.003
 FiO2 (%) 40 [40 to 48] 40 [40 to 45] 40 [40 to 50] 0.27
 Pmax (cm H2O) 23 [18 to 28] 22 [18 to 27] 24 [19 to 30] < 0.001
 PEEP (cm H2O) 7 [5 to 10] 7 [5 to 10] 8 [5 to 10] 0.22
 Dynamic compliance (ml/cm H2O) 31 [23 to 41] 32 [25 to 43] 29 [22 to 37] < 0.001
 ΔP (cm H2O) 15 [12 to 19] 15 [12 to 18] 16 [13 to 20] < 0.001
 MP (10−3 J/min/kg PBW) 206 [145 to 298] 194 [136 to 280] 218 [156 to 339] < 0.001
Blood gas analysis results, median [IQR]
 PaO2 (mm Hg) 91 [77 to 110] 91 [77 to 109] 92 [78 to 112] 0.68
 PaCO2 (mm Hg) 37 [41 to 43] 38 [32 to 43] 37 [31 to 43] 0.53
 pHa 7.38 [7.33 to 7.44] 7.39 [7.35 to 7.44] 7.38 [7.32 to 7.43] < 0.001
 Bicarbonate (mmol/l) 23 [20 to 27] 24 [21 to 27] 22 [19 to 26] < 0.001
  1. Abbreviations: ΔP respiratory system driving pressure, ARDS acute respiratory distress syndrome, BMI body mass index, COPD chronic obstructive pulmonary disease, FiO2 fraction of inspired oxygen, ICU intensive care unit, MAP mean arterial pressure, MP mechanical power of ventilation normalized for predicted bodyweight, PaCO2 arterial carbon dioxide tension, PaO2 arterial oxygen tension, PBW predicted body weight, PEEP positive end-expiratory pressure, Pmax maximum airway pressure; SOFA sepsis-related organ failure assessment score, SpO2 peripheral pulse oximetry, LOS length of stay, VFD–28 days ventilator-free and alive
  2. aRisk of death is based on the APACHE IV score