Table 2.
Primary and secondary outcomes.
| Low Tidal Volume (n = 50) | Intermediate Tidal Volume (n = 48) | Absolute Difference (95% CI) | Effect Estimate (95% CI) | value of p | |
|---|---|---|---|---|---|
| Primary outcome | |||||
| Development of ARDS within 7 days | 5/42 (11.9) | 4/44 (9.1) | 2.81 (−10.46 to 16.09)a | 1.16 (0.62 to 2.17)c | 0.735 |
| Secondary outcomes | |||||
| Development of pneumonia within 7 days | 9/43 (20.9) | 9/44 (20.5) | 0.48 (−17.00 to 17.95)a | 1.01 (0.60 to 1.71)c | 0.999 |
| Development of atelectasis within 7 days | 9/43 (20.9) | 12/44 (27.3) | −6.34 (−24.75 to 12.06)a | 0.83 (0.48 to 1.44)c | 0.617 |
| Ventilator–free days on day 28 | 24.0 (0.0–27.0) | 20.0 (10.2–24.0) | 3.68 (0.21 to 7.14)b | 4.00 (−1.02 to 9.02)b | 0.122 |
| Duration of ventilation, days | 3.0 (1.0–6.0) | 7.0 (3.0–14.0) | −4.29 (−6.94 to −1.64)b | 0.98 (0.55 to 1.75)e | 0.950 |
| In survivors, days | 2.0 (1.0–4.8) | 6.5 (3.0–10.0) | −4.67 (−9.62 to 0.29)b | ||
| ICU length of stay, days | 7.0 (3.8–12.2) | 13.5 (6.8–20.5) | −6.07 (−10.01 to −2.13)b | 1.26 (0.79 to 2.02)d | 0.327 |
| In survivors, days | 8.0 (6.0–13.5) | 13.0 (6.5–18.5) | −4.71 (−10.41 to 0.99)b | ||
| Hospital length of stay, days | 23.5 (13.2–47.2) | 29.5 (15.0–42.2) | −5.29 (−17.29 to 6.70)b | 0.86 (0.53 to 1.38)d | 0.527 |
| In survivors | 31.0 (15.0–58.0) | 32.5 (18.0–43.0) | −1.20 (−15.9 to 13.50)b | ||
| Mortality | |||||
| ICU | 11/49 (22.4) | 8/45 (17.8) | 4.67 (−11.95 to 21.29)a | 1.14 (0.73 to 1.78)c | 0.615 |
| Hospital | 13/46 (28.3) | 8/44 (18.2) | 10.08 (−7.72 to 27.88)a | 1.29 (0.85 to 1.96)c | 0.322 |
| 28–day | 12/43 (27.9) | 8/43 (18.6) | 9.30 (−8.92 to 27.52)a | 2.70 (1.01 to 7.22)d | 0.047 |
| 90–day | 12/42 (28.6) | 10/43 (23.3) | 5.32 (−13.77 to 24.41)a | 2.63 (0.98 to 7.02)d | 0.054 |
Data are median (quartile 25–quartile 75) or N/Total (%). ARDS, acute respiratory distress syndrome; CI, confidence interval; ICU, intensive care unit. aEffect estimate is the risk difference from a generalized linear model with binomial distribution and identity link. bEffect estimate is the median difference from a median regression. cEffect estimate is the risk ratio from a Wald likelihood ratio approximation test and the value of p estimated from a Fisher’s exact test. dEffect estimate is the hazard ratio from a Cox proportional hazard model. eEffect estimate is the subdistribution hazard ratio from a Fine-Gray competing risk model with 28-day mortality as a competing risk.