Table 1.

Clinical characteristics, respiratory parameters and outcomes of the study population

	Overall population n = 241
Clinical characteristics
Age (years)	66 [58–73]
Gender (male)	189 (78%)
SOFA score at ICU admission	5 [4–8]
BMI (kg/m2)	27 [25–30]
Charlson comorbidity index	1 [1, 2]
Onset of symptoms (days)	7 [3–9]
Hospital LOS before ICU (days)	2 [1–5]
Hospital LOS before CMV (days)	2 [1–5]
Gas exchange, at first day of CMV
pH	7.41 [7.36–7.46]
PaO2/FiO2 (mmHg)	142 [102–216]
PaCO2 (mmHg)	44 [38–52]
Ventilator settings and variables, at first day of CMV
Tidal volume (ml/kg of ideal body weight)	7.8 [6.9–8.8]
Set respiratory rates (breaths/min)	16 [14–20]
Total PEEP (cmH2O)	12 [10–13]
FiO2 (%)	60 [50–70]
Plateau pressure (cmH2O)	23 [20–26]
Driving pressure (cmH2O)	11 [9–13]
Static compliance of the respiratory system (ml/cmH2O)	48 [39–60]
Respiratory treatments before CMV
NIV failure	110 (46%)
HFOT failure	27 (11%)
None	104 (43%)
Adjunctive therapies during ICU stay
Prone position	202 (84%)
Neuromuscular blockers > 24 h	212 (88%)
V–V ECMO	5 (2%)
V–A ECMO	1 (0.4%)
Outcomes
ICU mortality	71 (29%)
60-day mortality	78 (32%)
Length of CMV (days)	12 [7–16]
ICU LOS (days)	15 [9–25]
Hospital LOS (days)	30 [18–41]

Data are expressed as median and interquartile range [IQR] or number (%)

SOFA sequential organ failure assessment, ICU intensive care unit, BMI body mass index, LOS length of stay, CMV controlled mechanical ventilation, PaO₂ partial pressure of arterial oxygen, PaO₂/FiO₂ ratio between partial pressure of arterial oxygen and fraction of inspired oxygen, PaCO₂ partial pressure of carbon dioxide, PEEP positive end-expiratory pressure, FiO₂ fraction of inspired oxygen, NIV non-invasive ventilation, HFOT high flow oxygen therapy, V–V veno–venous, V–A veno–arterial, ECMO extracorporeal membrane oxygenation