Fig. 4. Effects of ventilator mode and level of assistance on peak (Ppeak) and mean inspiratory airway pressure (Pmean). Ppeakis similar and Pmeanslightly lower when ventilator mode changes from pressure support ventilation (PSV) to neurally adjusted ventilatory assist (NAVA). Both Ppeakand Pmeanrise as NAVA gain increases from 1 to 4 cm H2O/μV diaphragm electrical activity (NAVA1,2,3,4). Data are means ± SEM; *P < 0.05.