The timed inspiratory effort: a promising index of mechanical ventilation weaning for patients with neurologic or neuromuscular diseases.

BACKGROUND: The aim of this study was to evaluate the performance of the recently described timed inspiratory effort (TIE) index in comparison with 4 other previously reported indices as to the weaning outcome in patients with neurologic or neuromuscular disorders.

METHODS: This observational prospective study included subjects undergoing weaning from mechanical ventilation. The performance of the indices was evaluated by calculation of the area under the receiver operating characteristic curves. The areas under the curve were compared using the Hanley and McNeil method. P values<.05 were considered significant.

RESULTS: Seventy-two subjects (57±20 y old) were selected for the study. Forty-three subjects were weaned, and 21 died during the study period. The mean duration of mechanical ventilation was 22.3±19.4 d. The areas under the curve of 5 weaning predictors (TIE index, integrative weaning index, noninvasive tension-time index, maximum inspiratory pressure, and breathing frequency/tidal volume index) were significantly higher than those of the other indices. The TIE index had the largest area under the curve (0.96±0.02) in comparison with the integrative weaning index (0.82±0.05, P=.009), noninvasive tension-time index (0.80±0.05, P=.001), maximum inspiratory pressure (0.77±0.06, P=.001), and breathing frequency/tidal volume index (0.72±0.06, P=.001).

CONCLUSIONS: In patients with neurologic or neuromuscular impairment, the TIE index had a better performance than the best weaning indices used in clinical practice.