Table 1. Demographic and Clinical Characteristics of the Enrolled Patients.
| Characteristic | No. (%) | |
|---|---|---|
| Sighs + usual care | Usual care alone | |
| Total No. of participants | 261 | 263 |
| Age, mean (SD), y | 43.7 (19.1) | 44.2 (19.2) |
| Sex | ||
| Male | 197 (75.5) | 197 (74.9) |
| Female | 64 (24.5) | 66 (25.1) |
| Race and ethnicitya | 260 | 262 |
| American Indian or Alaska Native | 2 (0.8) | 0 |
| Asian | 1 (0.4) | 4 (1.5) |
| Black or African American | 55 (21.2) | 52 (19.8) |
| Hispanic or Latino | 43 (16.5) | 42 (16.0) |
| White | 202 (77.7) | 203 (77.5) |
| Multiple racial and ethnic categories | 0 | 3 (1.1) |
| Smoking status, No. | 199 | 183 |
| Current/past | 134 (67.3) | 103 (56.3) |
| Never | 65 (32.7) | 80 (43.7) |
| Entry criteria | ||
| Traumatic brain injury | 159 (60.9) | 165 (62.7) |
| >1 Long bone fractures | 44 (16.9) | 47 (17.9) |
| In shock on arrival in EDb | 81 (31.0) | 96 (36.5) |
| Lung contusion | 107 (41.0) | 111 (42.2) |
| >6 U of blood products | 94 (36.0) | 89 (33.8) |
| Arterial blood gases on enrollment | 234 | 243 |
| pH, mean (SD) | 7.36 (0.08) | 7.37 (0.08) |
| Paco2, mean (SD), mm Hg | 39.1 (7.4) | 38.6 (7.8) |
| Pao2, mean (SD), mm Hg | 157.4 (84.2) | 152.5 (79.9) |
| Fio2, mean (SD), mm Hg [No.] | 48.1 (19.0) [230] | 47.1 (17.2) [228] |
| Pao2/Fio2 ratio, mean (SD) [No.] | 348.6 (171.9) [230] | 349.8 (214.0) [228] |
| Pao2/Fio2 ratio categorical | ||
| >300 (Best) | 130 (56.5) | 128 (56.1) |
| >200-300 | 57 (24.8) | 55 (24.1) |
| >100-200 | 35 (15.2) | 37 (16.2) |
| ≤100 (Worst) | 8 (3.5) | 8 (3.5) |
| PEEP, mean (SD), cm H2O [No.] | 6.8 (2.5) [222] | 7.1 (3.6) [227] |
| Hours with ventilator prior to randomization, mean (SD) | 17.1 (5.8) | 17.0 (5.9) |
| Ventilator mode, No. | 260 | 263 |
| Assisted mechanical ventilation | 98 (37.7) | 106 (40.3) |
| Controlled mechanical ventilation | 69 (26.5) | 66 (25.1) |
| Pressure control ventilation | 45 (17.3) | 45 (17.1) |
| Synchronized intermittent mandatory ventilation | 39 (15.0) | 40 (15.2) |
| Other | 9 (3.4) | 6 (2.2) |
| Inspiratory (set) tidal volume, mean (SD), mL [No.] | 502.9 (97.0) [258] | 501.2 (92.3) [261] |
| Set tidal volume/PBW, mean (SD), mL [No.] | 7.4 (1.4) [258] | 7.3 (1.4) [261] |
| Injury Severity Score, mean (SD) [No.]c | 28.8 (12.9) [256] | 29.9 (11.7) [259] |
| RASS scale, mean (SD) [No.]d | −2.0 (2.1) [256] | −2.0 (2.3) [261] |
| BMI [No.] | 261 | 263 |
| <30 | 161 (61.7) | 169 (64.3) |
| ≥30 | 100 (38.3) | 94 (35.7) |
| Infiltrates on initial chest x-ray or CT, No. | 258 | 261 |
| None | 181 (70.2) | 178 (68.2) |
| Localized | 22 (8.5) | 21 (8.0) |
| Generalized (bilateral) | 37 (14.3) | 49 (18.8) |
| Diffuse | 18 (7.0) | 13 (5.0) |
| Medications | 260 | 263 |
| For sedatione | 249 (95.8) | 252 (95.8) |
| For hypotensionf | 98 (37.7) | 90 (34.2) |
| For paralysis | 31 (11.9) | 24 (9.1) |
| To increase cardiac outputg | 3 (1.2) | 3 (1.1) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); CT, computed tomography; ED, emergency department; Fio2, fraction of inspired oxygen; PBW, predicted body weight; PEEP, positive end-expiratory pressure; RASS, Richmond Agitation Sedation Scale.
Race and ethnic data were self-reported by participants within fixed categories based on National Institutes of Health Diversity Program.
Systolic blood pressure <90 mm Hg.
Score range, 0 (no injury) to 75 (not survivable).
Score range, +4 (combative) to −5 (unarousable). Score information is available in eTable 1 in Supplement 2.
Benzodiazepines, propofol, dexmedetomidine, haloperidol, quetiapine, and phenobarbital.
Norepinephrine, vasopressin, epinephrine, and phenylephrine.
Isoproterenol, dopamine, and inotropic agents.