Table 2. Primary and Secondary Outcomes.
| End point | Median (IQR) | Mean difference (sighs − usual care) | ||||
|---|---|---|---|---|---|---|
| Sighs + usual care (n = 259)a | Usual care alone (n = 261) | Unadjusted | Adjustedb | |||
| Estimated (95% CI) | P value | Estimated (95% CI) | P value | |||
| Primary outcome | ||||||
| Ventilator-free daysc | ||||||
| Overall | 18.4 (7.0 to 25.2) | 16.1 (1.1 to 24.4) | 1.9 (0.1 to 3.6) | .04 | 1.4 (−0.2 to 3.0) | .08 |
| Death excluded | 20.3 (14.2 to 25.8) | 19.5 (10.2 to 25.2) | 0.9 (−0.7 to 2.6) | .26 | 0.8 (−0.8 to 2.3) | .33 |
| Secondary outcomes | ||||||
| ICU-free days | ||||||
| Overall | 13.7 (2.0 to 20.6) | 11.9 (0.0 to 20.0) | 1.3 (−0.3 to 2.9) | .10 | 0.8 (−0.6 to 2.3) | .26 |
| Death excluded | 15.5 (7.8 to 21.2) | 14.0 (6.4 to 21.6) | 0.6 (−1.0 to 2.1) | .48 | 0.3 (−1.2 to 1.8) | .71 |
| Total ventilator-free daysd | ||||||
| Overall | 20.0 (9.0 to 25.0) | 17.0 (4.0 to 24.0) | 1.9 (0.2 to 3.6) | .03 | 1.4 (−0.1 to 2.9) | .07 |
| Death excluded | 21.0 (15.0 to 25.0) | 20.0 (11.5 to 25.0) | 1.0 (−0.6 to 2.5) | .22 | 0.8 (−0.7 to 2.2) | .30 |
Abbreviation: ICU, intensive care unit.
Patients randomized to sighs plus usual care received sighs for a median of 3 days (IQR, 1-7). Among those with a plateau pressure of ≤35 cm H2O (n = 183), the initial mean (SD) sigh volume was 994 (296) mL, 13.7 (4.2) mL/kg predicted body weight (PBW), or 192% (57%) of the set tidal volume. Among those with a plateau pressure >35 cm H2O (n = 37), the initial mean (SD) sigh volume was 905 (271) mL, 13.5 (3.6) mL/kg PBW, or 205% (138%) of the set tidal volume.
Models were adjusted for age, sex, smoking history, traumatic brain injury, >1 long bone fracture, shock, lung contusion, receipt of >6 units of blood products in the first 24 hours of care, Injury Severity Score, Pao2/Fio2 ratio ≤300 prior to randomization, and trial center. Missing values for Injury Severity Score and Pao2/Fio2 ratio were imputed using multiple imputation by chained equations. Results were pooled across 50 imputations using the Rubin rules for computing the total variance. Results from the complete case analyses are provided in eTable 2 in Supplement 2.
Defined as number of days of unassisted breathing to day 28 without having to reinstitute invasive ventilation. Patients who died before day 28 were assigned 0 ventilator-free days.
Defined as the number of 24-hour periods that were free from assisted ventilation to day 28 or death.