The development of (top to bottom) diaphragm electrical activity (EA
), neuromechanical efficiency (NVE), and neuroventilatory efficiency (NME) during pressure support of 10 above 5 cm H
O of PEEP (PSV
) and throughout the spontaneous breathing trial (SBT) on CPAP of 5 cm H
O. On the X-axis: T1, T5, T10, T15, T30, and Tend indicate minutes 1, 5, 10, 15, and 30, as well as the last data obtained during the SBT. In the successfully extubated group, n = 35 at all time points. In the group for whom extubation failed, n = 17 at PSV10, T1, and T5; n=16 at T10 and T15; n=14 at T30 (three for whom SBT failed at 30 minutes and 11 who were initially extubated but were later reintubated or provided with noninvasive ventilation or died). Data were obtained for the remaining three patients meeting SBT exclusion criteria at T30. At Tend, n = 17 in the group for whom extubation failed. *Difference (P < 0.05) between failure and successfully extubated groups at the same time point. †Differences (P < 0.05) between PSV10 and other time points in the group for whom extubation failed. ‡Differences (P < 0.05) between PSV10 and other time points in the group that was successfully extubated.