Table 2.
Ventilator settings and ventilatory variables
| Ventilator settings/ventilatory variablesa | Ventilation periodsb | p | |||
|---|---|---|---|---|---|
| 1-PSb | 2-PSopt | 3-NAVA | 4-PSopt | ||
| Ventilator settings | |||||
| PS (cmH2O) | 12.4 (1.4) | 12.6 (1.6) | 13.0 (1.6) | 0.51 | |
| PEEP (cmH2O) | 5.8 (0.5) | 5.8 (0.6) | 5.8 (0.6) | 6.0 (0.6) | 0.30 |
| Flow trigger | 7.5 (2.3) | 7.3 (1.7) | 7.3 (1.7) | 7.3 (1.7) | 0.80 |
| NAVA level | 1.41 (0.23) | ||||
| NAVA trigger (μV) | 0.46 (0.12) | ||||
| FiO2 | 0.50 (0.4) | 0.51 (0.4) | 0.51 (0.4) | 0.51 (0.4) | 0.39 |
| Ventilatory variables | |||||
| V t (kg PBW) | 5.5 (4.2–6.8) | 5.8 (4.6–7.0) | 5.6 (3.4–7.4) | 5.4 (4.2–6.5) | 0.13 |
| maxEAdi (μV) | 11.5 (7.1–19.7) | 14.3 (9.2–22.0) | 11.5 (6.7–17.3) | 13.6 (8.3–20.7) | 0.55 |
| P max (cmH2O) | 19.6 (14.6–20.5) | 19.2 (15.2–21.6) | 18.0 (15.5–24.5) | 19.6 (14.6–21.0) | 0.85 |
| RR (bpm) | 44.4 (25.4–53.5) | 40.4 (29.3–51.9) | 37.1 (26.3–55.7) | 40.3 (30.2–53.2) | 0.92 |
| SpaO2 (%) | 97.5 (95.5–99.5) | 97.0 (95–99.0) | 98.0 (97.0–99.5) | 95.5 (94.5–97.5) | 0.02 |
| etCO2 (mmHg) | 32.8 (30.5–41.2) | 33.8 (31.6–40.9) | 34.2 (30.0–39.5) | 33.8 (30.0–41.2) | 0.93 |
etCO 2 End tidal CO2 level, maxEAdi highest electrical activity of the diaphragm for the breath, NAVA neurally adjusted ventilatory assist, PEEP positive end expiratory pressure, P max maximum airway pressure, PS b baseline pressure support, PS opt optimized PS, RR respiratory rate, V t tidal volume, SpaO 2 oxygen saturation by pulsioxymetry
aVentilator setting data are given as the mean, with 1 standard deviation (SD) given in parenthesis; Ventilatory variables data are given as the median, with the 25–75 interquartile range (IQR) given in parenthesis
bFour sequential 10-min periods of data were recorded after 20 min of ventilatory stabilization (wash-out): 1-PSb, baseline pressure support (PS) with the ventilator settings determined by the attending physician; 2-PSopt, PS after optimization; 3-NAVA, NAVA level set so that maximum inspiratory pressure (P max) equaled P max in PS; 4-PSopt, same settings as in 2-PSopt. Post hoc analysis did not show significant differences between periods