PT  - JOURNAL ARTICLE
AU  - de Souza, Leonardo Cordeiro
AU  - da Silva, Cyro Teixeira
AU  - Almeida, Jorge Reis
AU  - Lugon, Jocemir Ronaldo
TI  - Comparison of Maximal Inspiratory Pressure, Tracheal Airway Occlusion Pressure, and Its Ratio in the Prediction of Weaning Outcome: Impact of the Use of a Digital Vacuometer and the Unidirectional Valve
AID  - 10.4187/respcare.01489
DP  - 2012 Aug 01
TA  - Respiratory Care
PG  - 1285--1290
VI  - 57
IP  - 8
4099  - http://rc.rcjournal.com/content/57/8/1285.short
4100  - http://rc.rcjournal.com/content/57/8/1285.full
AB  - OBJECTIVE: To investigate the predictive value of the maximal inspiratory pressure obtained by a digital vacuometer using a unidirectional valve (PImaxUV) as to weaning outcome, and to compare its performance with the respiratory drive using airway occlusion pressure at 0.1 second (P0.1), and P0.1/PImaxUV. METHODS: Patients on mechanical ventilation for > 24 hours who fulfilled the weaning criteria were prospectively enrolled. Measurements of PImaxUV and P0.1 were accomplished with a digital vacuometer with a unidirectional valve that allows only exhalation. Measured values were electronically recorded and stored on the digital vacuometer measurement device. Cutoff points for the used parameters were: absolute values of PImaxUV > 30 cm H2O, P0.1 < 2.3 cm H2O, and P0.1/PImaxUV < 0.10. Receiver operating characteristic curves were calculated to compare the predictive values of the indexes. RESULTS: One hundred three subjects completed the test. The areas under the receiver operating characteristic curve were 0.79 ± 0.04, 0.65 ± 0.05, and 0.74 ± 0.04 for PImaxUV, P0.1, and P0.1/PImaxUV, respectively. The area under the receiver operating characteristic curve for PImaxUV was higher than for P0.1 and P0.1/PImaxUV, but statistical significance was only found against P0.1 (P = .007). CONCLUSIONS: Every studied index had only a modest performance regarding prediction of weaning outcome. Of note, PImaxUV values obtained by digital technology using a unidirectional valve performed better than historically reported using a conventional techniques, surpassing P0.1 and P0.1/PImaxUV in this regard.