Mechanical Power to Predict Ventilator Liberation in Patients With a Tracheostomy.

Abstract

Background: Mechanical power (MP) is useful for predicting the outcomes of attempts to liberate patients from mechanical ventilation. MP is computed based on measured variables derived to determine the power in joules required to breathe while receiving mechanical ventilation. The main objectives of this study were to calculate a cutoff value of MP that would predict successful liberation and to determine the prediction rate of liberation success based on this cutoff value. Methods: This was a single-center retrospective study. Data from 110 tracheostomized subjects receiving mechanical ventilation were analyzed. We divided subjects into two groups based on ventilator liberation outcome. Confounding factors in subject background were adjusted using propensity score matching (PSM). Statistically significant differences in MP at tracheostomy and liberation success between liberation success and failure groups were examined. We calculated the MP cutoff value for successful liberation using the area under the curve of the receiver operating characteristic (ROC) and its corresponding prediction rate of liberation success. Results: The number of subjects in the successful liberation group was 79 and that of the failed liberation group was 31. The MP cutoff value and corresponding prediction rate for liberation success were 256.5 J/min (area under the curve-ROC = 0.839) and 92.2%, respectively. After PSM, the low MP group (n = 36), divided based on the MP cutoff value, had a significantly higher liberation success rate than the high MP group (n = 36), with an odds ratio of 19.95 (CI 3.95, 91.23, P < .001). Conclusion: MP at tracheostomy was a strong predictor of successful ventilator liberation, and the prediction rate of liberation success based on the MP cutoff value was shown to be very high. We recommend that patients with low MP be actively considered for liberation. In contrast, those with high MP should continue weaning while simultaneously making early transfer arrangements if liberation is unsuccessful.