Fig. 2. Effects of ventilator mode and level of assistance on representative breathing pattern variables. Compared with pressure support ventilation (PSV), the most noticeable difference is the increase in mean inspiratory flow (Vt/Ti) as the neurally adjusted ventilatory assist (NAVA) gain is raised stepwise from 1 to 4 cm H²O/μV diaphragm electrical activity (NAVA^1,2,3,4). There is no significant change in respiratory rate (RR) or inspiratory duty cycle (Ti/Tt). Tidal volume (Vt) differs significantly at the highest NAVA gain (NAVA⁴). Data are means ± SEM; *P < 0.05.