Table 1.
Characteristics of the Study Groups at Inclusion, Ventilatory Settings, and Clinical Outcome and Mechanical Variables before and after NIV
| Clinical Variables | COVID-19 (n = 30) | Non–COVID-19 (n = 30) | P Value | ||||
|---|---|---|---|---|---|---|---|
| Age, yr | 68 (57–77) | 68 (57–78) | 0.9 | ||||
| Sex, M | 23 (77) | 22 (73) | 0.9 | ||||
| BMI, kg/m2 | 24 (21–27) | 24 (20–26) | 0.9 | ||||
| Charlson index score | 3 (2–4) | 4 (2–5) | 0.1 | ||||
| Kelly scale score | 1 (1–1) | 1 (1–1) | 0.9 | ||||
| SOFA score | 3 (3–4) | 3 (3–4) | 0.9 | ||||
| PaO2/FiO2, mm Hg* | 127 (100–138) | 124 (100–133) | 0.9 | ||||
| PaO2/FiO2 2 h after NIV, mm Hg | 133 (118–155) | 139 (119–158) | 0.4 | ||||
| pH | 7.48 (7.46–7.5) | 7.48 (7.44–7.5) | 0.7 | ||||
| pH after NIV | 7.45 (7.44–7.46) | 7.46 (7.43–7.48) | 0.5 | ||||
| PaCO2, mm Hg | 33 (30–38) | 34 (30–40) | 0.7 | ||||
| PaCO2 after NIV | 35 (32–37) | 35 (32–36) | 0.7 | ||||
| Blood lactate, mmol/L | 1 (0.7–1.2) | 1.7 (1–2.2) | 0.001 | ||||
| Serum creatinine, mg/dl | 0.7 (0.6–0.9) | 0.7 (0.5–0.9) | 0.8 | ||||
| D-dimer, mg/dl | 1,310 (862–9,400) | 815 (540–1,233) | 0.01 | ||||
| PEEP, cm H2O† | 10 (8–10) | 10 (8–11) | 0.7 | ||||
| PSV, cm H2O† | 12 (10–12) | 12 (10–16) | 0.2 | ||||
| ETI | 9 (30) | 11 (37) | 0.8 | ||||
| 28-d mortality | 6 (20) | 5 (17) | 0.9 | ||||
| Mechanical Variables | Baseline | 2 Hours after NIV | P Value | Baseline | 2 Hours after NIV | P Value | Interaction Test (ANOVA) |
|---|---|---|---|---|---|---|---|
| ΔPes, cm H2O | 12.5 (11.8–17.3) | 7.6 (6–10) | <0.0001 | 32 (25–38) | 18 (12–34) | <0.0001 | 0.1 |
| ΔPl, cm H2O | 12.5 (11.8–17.3) | 18.4 (16.9–21.3) | <0.0001 | 32 (25–38) | 32 (26–43) | 0.1 | 0.1 |
| RR, breaths/min | 28 (25–30) | 24 (21–26) | <0.0001 | 35 (30–41) | 31 (24–38) | 0.02 | 0.1 |
| V˙e, L/min | 20 (17–23) | 18 (15–22) | 0.1 | 27 (23–32) | 24 (20–28) | 0.004 | 0.6 |
| Vte, ml/kg of PBW | 9.2 (8.1–10.3) | 10.1 (8.7–11.2) | 0.3 | 10.9 (9.3–12) | 10.2 (9.9–12) | 0.8 | 0.6 |
| Dynamic compliance, ml/cm H2O | 55 (40–69) | 41 (31–52) | 0.1 | 25 (19–31) | 21 (16–34) | 0.7 | 0.2 |
| Dynamic mechanical power, J/min | 27 (19–40) | 56 (41–60) | <0.0001 | 95 (68–107) | 102 (66–130) | 0.1 | 0.2 |
Definition of abbreviations: BMI = body mass index; COVD-19 = coronavirus disease; ETI = endotracheal intubation; IQR = interquartile range; NIV = noninvasive mechanical ventilation; PBW = predicted body weight; PEEP = positive end-expiratory pressure; Pes = esophageal pressure; Pl = dynamic transpulmonary pressure; PSV = pressure support value; RR = respiratory rate; SOFA = Sequential Organ Failure Assessment; Vte = expiratory tidal volume.
Data are presented as number (percentage) for dichotomous values or median (IQR) for continuous values.
The values of the PaO2/FiO2 ratio used for matching these groups as well as pH and Pco2 values were those measured during high-flow nasal oxygen (see inclusion criteria earlier) immediately before starting NIV.
PEEP and PSV values reported were those measured during the first 2 hours of NIV.