Ventilatory management and illness severity of the 2377 invasively ventilated female and male patients with acute respiratory distress syndrome (ARDS)
| Females | Males | p-value# | |
| Subjects | 905 | 1472 | |
| Invasive ventilation settings at ARDS onset (day 1) | |||
| Patients undergoing controlled ventilation | 631 (70.6) | 980 (68.1) | 0.1995 |
| Set respiratory rate breaths·min−1 | 18.5±6.1 | 18.7±10.0 | 0.9509 |
| Total respiratory rate breaths·min−1 | 20.6±6.4 | 20.9±9.7 | 0.7230 |
| Tidal volume mL·kg−1 IBW | |||
| All patients | 8.2±2.1 | 7.2±1.6 | <0.0001 |
| Patients with controlled ventilation | 8.0±2.0 | 7.1±1.5 | <0.0001 |
| Patients with spontaneous ventilation | 8.6±2.2 | 7.5±1.8 | <0.0001 |
| p-value (control versus spontaneous ventilation) | 0.0005 | 0.0003 | |
| Lower tidal volume¶ | 424 (49.6) | 1039 (74.2) | <0.0001 |
| Set PEEP cmH2O | 8.5±3.4 | 8.4±3.3 | 0.9046 |
| Peak pressure+ cmH2O | 28.0±8.6 | 26.5±7.9 | <0.0001 |
| Dynamic compliance mL·cmH2O−1 | 27.31±22.83 | 34.65±32.61 | <0.0001 |
| Patients in whom PPLAT was measured | 371 (41.0) | 583 (39.6) | 0.5025 |
| PPLAT cmH2O§ | 24.1±6.0 | 22.6±6.1 | 0.0003 |
| Driving pressure cmH2O§ | 15.7±5.6 | 14.1±5.4 | 0.0001 |
| Standardised minute ventilation L·min−1ƒ | 9.61±4.4 | 11.53±5.1 | 0.0001 |
| Standardised minute ventilation L·min−1·kg−1 IBWƒ | 0.18±0.09 | 0.17±0.07 | <0.0001 |
| Gas exchange (day 1) | |||
| PaO2/FIO2 mmHg | 162.1±68.7 | 159.6±67.5 | 0.4261 |
| SpO2 | 96.0 (93.0–98.0) | 96.0 (93.0–98.0) | 0.9153 |
| PaCO2 mmHg | 45.2±15.5 | 46.5±14.6 | 0.0008 |
| <35 mmHg | 190 (21.3) | 244 (16.7) | 0.0061 |
| 35–45 mmHg | 341 (38.1) | 535 (36.7) | 0.4804 |
| ≥45 mmHg | 363 (40.6) | 679 (46.6) | 0.0047 |
| pH | 7.32±0.13 | 7.33±0.12 | 0.8145 |
| Severity profile (day 1) | |||
| ARDS severity | 0.8743 | ||
| Mild | 275 (30.4) | 439 (29.8) | |
| Moderate | 423 (46.7) | 683 (46.4) | |
| Severe | 207 (22.9) | 350 (23.8) | |
| SOFA score## | 9.9±4.0 | 10.1±4.0 | 0.1713 |
| Nonpulmonary SOFA score## | 6.7±4.0 | 6.9±3.9 | 0.2266 |
| FIO2 | 0.6 (0.5–0.9) | 0.6 (0.5–0.9) | 0.7265 |
| Adjunctive measures (first 48 h) | |||
| Neuromuscular blockade | 160 (17.7) | 245 (16.6) | 0.5144 |
| Recruitment manoeuvres | 173 (19.1) | 251 (17.1) | 0.2017 |
| Prone positioning | 48 (5.3) | 65 (4.4) | 0.3231 |
| ECMO | 36 (4.0) | 27 (1.8) | 0.0016 |
| Inhaled vasodilators | 62 (6.9) | 65 (4.4) | 0.0104 |
| HFOV | 1 (0.1) | 5 (0.3) | 0.4175 |
| None of the above | 578 (63.9) | 1003 (68.1) | 0.0322 |
Data are presented as n, n (%), mean±sd or median (interquartile range), unless otherwise stated. IBW: ideal body weight; PEEP: positive end-expiratory pressure; PPLAT: plateau pressure; PaO2: arterial oxygen partial pressure; FIO2: inspiratory oxygen fraction; SpO2: peripheral oxygen saturation; PaCO2: partial pressure of carbon dioxide; SOFA: Sequential Organ Failure Assessment; ECMO: extracorporeal membrane oxygenation; HFOV: high-frequency oscillatory ventilation. #: comparison of male versus female patients; ¶: lower tidal volume was defined as tidal volume ≤8 mL·kg−1 IBW; +: for peak pressure measurements, patients receiving HFOV or ECMO were excluded; §: PPLAT and driving pressure values are limited to patients in whom this value was reported, and in whom either an assist control mode was used or, where a mode permitting spontaneous ventilation was used, the set and total respiratory rates were equal (patients receiving HFOV or ECMO were also excluded); ƒ: standardised minute ventilation was calculated as minute ventilation×PaCO2/40; ##: for all SOFA scores, where data points were missing, this value was omitted and the denominator adjusted accordingly.