Table 2.
Clinical and Physiological Features of the Study Population at Baseline and after 2 Hours of NIV
| Feature | Overall | NIV Failure | NIV Success | P Value |
|---|---|---|---|---|
| Baseline RR, bpm | 36 (27–44) | 34 (27–42) | 36 (27–45) | 0.8 |
| RR after 2 h of NIV, bpm | 30 (24–37) | 31 (25–37) | 30 (24–37) | 0.6 |
| Baseline ΔPl (ΔPes), cm H2O | 35 (26–40) | 38 (32–42) | 32.5 (24–39) | 0.1 |
| ΔPes after 2 h of NIV, cm H2O | 19.5 (12.5–31) | 31.5 (30–36) | 11 (8–15) | <0.0001 |
| ΔPl after 2 h of NIV, cm H2O | 37 (30–43) | 39.5 (37.5–42.3) | 30.5 (28–43.5) | 0.04 |
| Baseline e, L/min | 28.1 (25.6–34.7) | 28.3 (25.8–32.3) | 27.4 (22.2–28.9) | 0.6 |
| e after 2 h of NIV, L/min | 23.3 (18.2–27.3) | 27.2 (25–27.8) | 19.8 (16.5–25) | 0.07 |
| Baseline Vte, ml/kg of PBW | 11 (9–12) | 11 (9.5–12.3) | 10.9 (9–11.2) | 0.7 |
| Vte after 2 h of NIV, ml/kg of PBW | 11 (10–12) | 11 (10–12.3) | 10.8 (8.5–12) | 0.5 |
| Baseline Vte/ΔPL ratio, ml/kg/cm H2O | 0.32 (0.28–0.57) | 0.31 (0.29–0.57) | 0.33 (0.27–0.4) | 0.3 |
| Vte/ΔPL ratio after 2 h of NIV, ml/kg/cm H2O | 0.31 (0.25–0.39) | 0.36 (0.21–0.44) | 0.29 (0.26–0.31) | 0.1 |
| HACOR score | 6 (5–8) | 6.5 (4.8–8) | 6 (6–7) | 0.5 |
| HACOR score after 2 h of NIV | 6 (5–6) | 6 (4.8–6.5) | 5.5 (4–6) | 0.4 |
Definition of abbreviations: bpm = breaths/min; ΔPes = tidal change in esophageal pressure; ΔPl = tidal change in dynamic transpulmonary pressure; HACOR = Heart Rate, Acidosis, Consciousness, Oxygenation and Respiratory Rate; NIV = noninvasive mechanical ventilation; PBW = predicted body weight; RR = respiratory rate; Vte = expiratory Vt.
Data are presented as median (interquartile range).