Table 2.
Daily characteristics of study patients*
| Characteristics | Day 1 | Day 2 | Day 3 |
|---|---|---|---|
| Total number of patients | 73 | 73 | 73 |
| Laboratory tests, median (IQR) | |||
| Pao2/Fio2 (mmHg) | 110.0 (80.0–158.5) | 141.6 (104.7–177.2) | 156.8 (113.3–193.8) |
| Pao2 (mmHg) | 76.0 (62.7–89.4) | 78.5 (67.1–89.7) | 74.5 (66.2–85.6) |
| Paco2 (mmHg) | 46.4 (40.0–51.3) | 48.5 (43.3–53.0) | 47.8 (43.3–52.7) |
| Arterial pH | 7.38 (7.31–7.444) | 7.41 (7.35–7.46) | 7.43 (7.36–7.48) |
| Vital signs, median (IQR) | |||
| Mean arterial pressure | 79 (66–93) | 82 (71–94) | 88 (75–97) |
| Urine output (24 h) | 2180 (1300–3150) | 3535 (2402–4687) | 3467 (2336–4695) |
| Ventilatory support | |||
| Previous use of non-invasive ventilation | 20/70 (28.6%) | na | na |
| Mode of ventilation | |||
| Controlled | 64/70 (91.4%) | 54/70 (77.1%) | 51/67 (76.1%) |
| Assisted | 6/70 (8.6%) | 16/70 (22.9%) | 16/67 (23.9%) |
| Tidal volume (mL/kg PBW), median (IQR) | 6.7 (6.0–7.5) | 6.7 (6.0–7.5) | 6.7 (6.1–7.4) |
| PEEP (cmH2O), median (IQR) | 12 (10–14) | 12 (10–14) | 12 (10–14) |
| Fio2 (mmHg), median (IQR) | 0.70 (0.52–0.80) | 0.60 (0.50–0.70) | 0.50 (0.40–0.65) |
| Peak airway pressure (cmH2O), median (IQR) | 28.5 (25.2–30.0) | 26.0 (20.5–29.5) | 26.0 (23.8–30.0) |
| Driving pressure (cmH2O),† median (IQR) | 12.0 (7.0–16.5) | 10.0 (6.0–15.0) | 11.0 (9.0–11.0) |
| Dynamic compliance (mL/cmH2O),‡ median (IQR) | 28.6 (21.8–34.0) | 31.7 (25.4–39.6) | 30.0 (25.7–34.6) |
| Clinical support | |||
| ECMO§ | 4 (5.5%) | 4 (5.5%) | 4 (5.5%) |
| Tracheostomy | 0/72 (0.0%) | 1/69 (1.4%) | 1/70 (1.4%) |
| Renal replacement therapy | 0/72 (0.0%) | 3/68 (4.4%) | 4/69 (5.8%) |
| Vasopressor or inotropic therapy | 59/72 (81.9%) | 58/70 (82.9%) | 59/70 (84.3%) |
| Norepinephrine | 42/72 (58.3%) | 48/70 (68.6%) | 39/70 (55.7%) |
|
0.15 (0.10–0.20) | 0.10 (0.05–0.20) | 0.10 (0.08–0.20) |
| Angiotensin II | 35/72 (48.6%) | 36/70 (51.4%) | 37/70 (52.9%) |
|
10.0 (5.0–20.0) | 10.0 (5.0–20.0) | 10.0 (5.0–20.0) |
| Neuromuscular blocking agents | 53/70 (75.7%) | 43/69 (62.3%) | 39/70 (55.7%) |
| Prone positioning | 28/70 (40.0%) | 36/70 (51.4%) | 29/69 (42.0%) |
| Duration (h), median (IQR) | 12 (9–18) | 16 (9–18) | 14 (9–16) |
ECMO = extracorporeal membrane oxygenation; Fio2 = fraction of inspired oxygen; IQR = interquartile range; na = not applicable; Paco2 = arterial partial pressure of carbon dioxide; Pao2 = arterial partial pressure of oxygen; PBW = predicted body weight; PEEP = positive end-expiratory pressure.
Percentages may not total 100 because of rounding.
Calculated as plateau pressure minus PEEP and available only in seven patients (9.6%) on Day 1, in 13 patients (17.8%) on Day 2 and in 13 patients (17.8%) on Day 3.
Calculated as tidal volume divided by the [peak pressure minus PEEP] and available only in 22 patients (30.1%) on Day 1, in 26 patients (35.6%) on Day 2 and in 33 patients (45.2%) on Day 3.
All but one patient receiving ECMO in the first 3 days were transferred from other centres already receiving mechanical ventilation for a period.