Table 1.

Baseline demographics of the subset of patients with complete data (n = 446)

Patient characteristic	Value
Age, years	50.6 ± 16.1
Female	184 (41.3%)
Low tidal volume ventilation	222 (49.8%)
Initial P/F ratio	129 ± 58
APACHE III	83.2 ± 28.4
Mean PaO2 (mmHg)	79.1 ± 17.6
Mean FiO2 (%)	54.1 ± 14.7
Mean PEEP (cm H20)	8.5 ± 3.1

All values are given as mean ± SD or n (%)

APACHE Acute Physiology and Chronic Health Evaluation, FiO₂ fractional inspired oxygen, PEEP positive end-expiratory pressure, PaO₂ arterial oxygen tension, P/F PaO₂/FiO₂