Table 2.
Baseline respiratory mechanics and clinical outcomes
| Variables | COVID-19 ARDS | Non-COVID ARDS | |||||
|---|---|---|---|---|---|---|---|
| Entire group N = 23 | Entire group N = 145 | P valuea | PaO2/FiO2-matched N = 23 | P valuea | Compliance-matched N = 23 | P valuea | |
| Arterial blood gas analysis | |||||||
| pH | 7.37 (7.34–7.39) | 7.34 (7.28–7.40) | 0.173 | 7.36 (7.26–7.40) | 0.291 | 7.34 (7.28–7.41) | 0.568 |
| PaCO2, mmHg | 44 (40–49) | 49 (40–55) | 0.139 | 48 (45–54) | 0.071 | 46 (37–54) | 0.860 |
| PaO2, mmHg | 75 (66–80) | 71 (62–85) | 0.467 | 79 (65–93) | 0.391 | 69 (55–78) | 0.097 |
| HCO3, mEq/L | 24.9 (24.1–28.4) | 24.2 (21.5–27.3) | 0.161 | 23.3 (21–28.6) | 0.191 | 23.3 (18.6–28.6) | 0.240 |
| Ventilator FiO2 | 0.7 (0.6–0.8) | 0.8 (0.65–1.0) | 0.047 | 0.75 (0.6–0.9) | 0.537 | 0.75 (0.7–1.0) | 0.221 |
| PaO2/FiO2 ratio, mmHg | 107 (92–132) | 96 (74–120) | 0.037 | 107 (92–131) | 1.000 | 90 (72–104) | 0.007 |
| PEEP, cmH2O | 12 (9–13) | 10 (8–11) | 0.016 | 10 (7–10) | 0.063 | 10 (8–11) | 0.135 |
| Driving pressure, cmH2O | 13 (12–16) | 18 (15–21) | < 0.001 | 18 (15–22) | 0.001 | 15 (13–18) | 0.096 |
| Respiratory rate, breaths/min | 21 (19–27) | 27 (24–30) | 0.002 | 26 (25–30) | 0.012 | 24 (21–30) | 0.116 |
| Tidal volume per PBW, mL/kg | 6.3 (5.6–7.0) | 6.6 (6.0–7.3) | 0.126 | 6.4 (5.9–7.2) | 0.734 | 6.5 (5.9–9.0) | 0.177 |
| Minute ventilation per PBW, mL/kg/min | 140 (123–171) | 177 (145–200) | < 0.001 | 167 (133–193) | 0.044 | 173 (141–194) | 0.003 |
| Static respiratory system compliance, mL/cmH2O | 27.2 (21.9–32.7) | 21.9 (18.2–26.5) | 0.005 | 20.0 (15.6–27.2) | 0.008 | 27.2 (21.9–32.7) | 0.983 |
| Ventilatory ratio | 1.7 (1.4–2.0) | 2.2 (1.7–2.7) | < 0.001 | 2.1 (1.7–2.5) | 0.015 | 2.2 (1.7–2.6) | 0.002 |
| Laboratory results | |||||||
| White blood cell, 103/μL | 10.46 (6.53–16.04) | 13.36 (5.73–17.77) | 0.717 | 15.73 (13.14–23.71) | 0.008 | 10.01 (5.73–16.86) | 0.904 |
| Segmented neutrophil, 103/μL | 9.66 (5.88–14.57) | 11.42 (4.93–15.06) | 0.906 | 14.40 (11.53–19.56) | 0.014 | 9.56 (4.53–14.43) | 0.684 |
| Lymphocyte, 103/μL | 0.69 (0.48–0.86) | 0.43 (0.18–0.84) | 0.047 | 0.70 (0.27–0.98) | 0.895 | 0.51 (0.16–0.88) | 0.249 |
| C-reactive protein, mg/dL | 10.9 (6.3–19.8) | 13.5 (6.6–21.5) | 0.234 | 13.8 (7.6–21.5) | 0.449 | 19.2 (9.1–25.7) | 0.037 |
| RT-PCR for SARS-CoV-2 | |||||||
| Ct value for env gene | 23.01 ± 4.99 | ||||||
| Ct value for RdRp gene | 22.60 ± 5.22 | ||||||
| Adjunctive therapies | |||||||
| Inhaled nitric oxide | 8 (34.8%) | 56 (38.6%) | 0.725 | 4 (17.4%) | 0.179 | 8 (34.8%) | 1.000 |
| Renal replacement therapy | 4 (17.4%) | 29 (20.0%) | 1.000 | 2 (8.7%) | 0.665 | 7 (30.4%) | 0.491 |
| ECMO or ECCO2R | 3 (13.0%) | 7 (4.8%) | 0.141 | 0 (0.0%) | 0.233 | 2 (8.7%) | 1.000 |
| Tracheostomy | 12 (52.2%) | 59 (40.7%) | 0.300 | 15 (65.2%) | 0.369 | 6 (26.1%) | 0.070 |
| 90-days clinical outcome | |||||||
| Successful discontinuation of mechanical ventilation | 16 (69.6%) | 27 (18.6%) | < 0.001 | 5 (21.7%) | 0.005 | 4 (17.4%) | 0.001 |
| Dependent on mechanical ventilation | 2 (8.7%) | 11 (7.6%) | 5 (21.7%) | 1 (4.3%) | |||
| Death | 5 (21.7%) | 107 (73.8%) | 13 (56.6%) | 18 (78.3%) | |||
| Ventilator free days | 45 (0–82) | 0 (0–0) | < 0.001 | 0 (0–0) | 0.002 | 0 (0–0) | 0.002 |
ARDS acute respiratory distress syndrome, Ct value cycle threshold value, ECCO2R extracorporeal carbon dioxide removal, ECMO extracorporeal membrane oxygenation, FiO2 fraction of inspired oxygen, PaCO2 partial pressure of carbon dioxide, PaO2 partial pressure of oxygen, PBW predicted body weight, PEEP positive end expiratory pressure, RT-PCR reverse transcription polymerase chain reaction
aP values are for comparison between patients with COVID-19 ARDS and patients with non-COVID ARDS