Table 1.
Baseline characteristics of the study population
| Characteristic | Overall population (N = 40) |
FiO2 < 45% (N = 24) |
FiO2 ≥ 45% (N = 16) |
p value, FiO2 < 45% vs FiO2 ≥ 45% |
|---|---|---|---|---|
| Age (years) | 57 ± 15 | 55 ± 14 | 62 ± 16 | 0.17 |
| Female sex, n (%) | 16 (40%) | 8 (33.3%) | 8 (50%) | 0.29 |
| Monolateral/bilateral infiltrates, n (%) | 12 (30%)/28 (70%) | 8 (33%)/16 (67%) | 4 (25%)/12 (75%) | 0.57 |
| SOFA score | 4 (3–6) | 3.5 (3–6) | 4 (3–6) | 0.89 |
| Pulmonary/extrapulmonary cause of ARDS, n (%) | 19 (48%)/21 (53%) | 11 (46%)/13(54%) | 8 (50%)/8 (50%) | 0.80 |
| Infectious/non-infectious cause of ARDS, n (%) | 22 (56%)/18 (45%) | 14 (58%)/10 (42%) | 8 (50%)/8 (50%) | 0.60 |
| FiO2 | 40 (40–50) | 40 (40–40) | 50 (50–60) | < 0.0001* |
| Respiratory rate (bpm) | 22 (18–24) | 20 (18–24) | 24 (20–30) | 0.05* |
| Borg scale | 2 (1–3) | 1 (0–3) | 3 (2–4) | 0.02* |
| Comfort | 4 (3–5) | 4 (3–5) | 4 (3–5) | 0.81 |
| SpO2/FiO2 | 241 (196–249) | 248 (243–250) | 192 (161–199) | < 0.0001* |
| SAPS II | 36 ± 9 | 38 ± 8 | 35 ± 11 | 0.35 |
Normally distributed variables reported as mean ± standard deviation, non-normal variables reported as median (interquartile range). p values obtained by t test, Wilcoxon rank-sum test, or chi-square test as appropriate
ARDS acute respiratory distress syndrome, FiO2 inspired oxygen fraction, SAPS Simplified Acute Physiology Score, SOFA Sepsis-related Organ Failure Assessment, SpO2 peripheral oxygen saturation
*Data significant at p < 0.05