Figure 4

Continuous recording of ventilatory parameters for 12 hours (case 3). Figure demonstrates in the third patient the 24-hour evolution of FiO2 (Panel A), expiratory tidal volume (Panel B), mean airway pressure (Panel C), peak inspiratory pressure (Panel D), respiratory rate (Panel E) and Edi max (Panel F). Recording began with the establishment of NAVA. Upper panels: After starting NAVA, (A) FiO₂ gradually decreased to 35%, and (B) tidal volume became variable from one cycle to another ranging from 5 to 30 ml. Middle panels: Variability was also observed in measurements of pressure: (C) mean airway pressure, (D) peak inspiratory pressure. Bottom panels: (E) After starting NAVA, the respiratory rate became very variable over time. (F) Edi max corresponds to the peak of electrical activity of the diaphragm. The highest Edi values (recorded between 19:00 and 22:00) drove assistance with the highest pressures. A decrease in signal intensity was accompanied by a decrease in pressure, corresponding to an improvement in lung function. The requirement for oxygen decreased at the same time. Abbreviations: FiO₂, fraction of inspired oxygen; Edi, electrical activity of the diaphragm; NAVA, neurally adjusted ventilatory assist.