Study Populations and Protocols.

*Details obtained from a separate publication of a subgroup with trauma-induced ARDS by McKinley et al (n = 67)[34].PVL = pressure and volume-limitation, LIS = lung injury score[21], PEEP = positive end expiratory pressure, AC = volume cycled, P-AC = pressure assist control, V-AC = volume assist control, AC = assist control mode, PC = pressure control mode, PCIRV = pressure control inverse ratio ventilation, SIMV = synchronized intermittent mandatory ventilation, PS = pressure support, BW = body weight, PPLAT = plateau airway pressure, PIP = peak inspiratory pressure, LIP = lower inflection point, PaO2 = arterial partial pressure of arterial oxygen, PaCO2 = partial pressure of arterial carbon dioxide, SpO2 = oxygen saturation by pulse oximetry, FiO2 = fractional concentration of oxygen in inspired gas, NaHCO3− = sodium bicarbonate, RR = respiratory rate, IRV = inverse ratio ventilation, VT = tidal volume, HTV = high tidal volume, LTV = low tidal volume, PAWP = pulmonary artery wedge pressure.Formulae:**Dry BW: Actual body weight minus the estimated weight gain due to salt and water retention.§Predicted body weight (PBW): male PBW = 50+2.3 [height (inches) –60]; female PBW = 45.5+2.3 [height (inches) – 60]. Alternatively, male PBW = 50+0.91 (centimeters of height –152.4); female PBW = 45.5+0.91 (centimeters of height –152.4).†PBW based on actuarial data.‡IBW (kg) = height (meters)2×25.¶Actual Body Weight minus the estimated weight gain due to water and salt retention.Assessment:aPEEP: Line 1: We assessed for the presence of an explicit protocol, suggested guideline or titration of PEEP at physician discretion; Line 2: description of initial settings or titration to specific parameters; Line 3: details the range of PEEP permitted.bPEEP >20 cm H2O permitted if profoundly hypoxemic.cpH Thresholds: We assessed for a threshold pH value (or pH range) and strategies utilized to increase pH.