Table 1.
Patient Characteristics, Blood Gas and Ventilatory Variables
| Patient characteristics | Median (IQR) | |
|---|---|---|
| Age (years) | 54.0 (45.0–59.5) | |
| Male (%) | 90% | |
| BMI (kg/m2) | 36.0 (30.0–43.4) | |
| SOFA score | 8.0 (6.0–10.7) | |
| Duration between onset of symptoms and admission to ICU (days) | 10.5 (7.2–15.0) | |
| Respiratory support prior to admission (NIV/HFNC), No. (%) | 12 (60%) / 2 (10%) | |
| Duration of first prone positioning session, hours | 16.2 h (15.6–17.4) | |
| Length of ICU stay prior to prone positioning | 1 day (1–1.75) | |
| Arterial blood gas variables | Pre-prone positioning | During prone positioning |
| pH | 7.30 (7.23–7.35 | 7.30 (7.22–7.36) |
| PaO2 (kPa) | 12.5 (10.1–13.2) | 14.3 (12.7–20.4) |
| PaCO2 (kPa) | 7.0 (6.1–8.0) | 7.3 (6.6–8.5) |
| Ventilatory variables | ||
| Plateau airway pressure (cmH2O) | 26 (20–28) | 26 (22–29) |
| Tidal volume (mL) | 426 (391–461) | 436 (393–470) |
| PEEP (cmH2O) | 14 (10–16) | 14 (10–15) |
| FiO2 (%) | 70 (60–95) | 45 (36–55) |
| PaO2/FiO2 (mmHg) | 123 (100–154) | 286 (195–348) |
| Aa Gradient (mmHg) | 342 (275–507) | 114 (64–207) |
| CRS (ml/cmH2O) | 33.7 (30.1–43.0) | 32.5 (26.7–37.5) |
BMI body mass index, SOFA sequential organ failure assessment, NIV non-invasive ventilation, HFNO high flow nasal oxygen, PaO2 arterial partial pressure of oxygen, PaCO2 arterial partial pressure of carbon dioxide, PEEP positive end-expiratory pressure, FiO2 fraction of inspired oxygen, Aa alveolar-arterial, CRS static compliance