Intensive Care Medicine

, Volume 30, Issue 5, pp 830–836

A prospective, blinded evaluation of indexes proposed to predict weaning from mechanical ventilation

  • Giorgio Conti
  • Luca Montini
  • Mariano Alberto Pennisi
  • Franco Cavaliere
  • Andrea Arcangeli
  • Maria Grazia Bocci
  • Rodolfo Proietti
  • Massimo Antonelli
Original

DOI: 10.1007/s00134-004-2230-8

Cite this article as:
Conti, G., Montini, L., Pennisi, M.A. et al. Intensive Care Med (2004) 30: 830. doi:10.1007/s00134-004-2230-8

Abstract

Objective

To conduct a blinded evaluation of the predictors of weaning from mechanical ventilation.

Design

A prospective clinical study.

Setting

A 23-bed general intensive care unit.

Patients

Ninety-three non-selected patients, ventilated for more than 48 h.

Methods

The study had two steps: at first, patients’ data were used to select the cut-off value for weaning predictors (the minimal false classification). The cut-off value for each index was prospectively assessed in a group of 52 patients. The predictive performance of these indexes was evaluated by calculating the area under the receiver operating characteristic curve. In the prospective-validation set we used Bayes’ theorem to assess the probability of each test in predicting weaning. The physicians making decisions about the weaning process were always unaware of the predictive values. Weaning was considered successful if spontaneous breathing was sustained for more than 48 h after extubation.

Measurements and results

During the first 2 min after discontinuation of mechanical ventilation the following tests were performed: vital capacity, tidal volume, airway occlusion pressure (P0.1), minute ventilation, respiratory rate, maximal inspiratory pressure (MIP), respiratory frequency to tidal volume (f/VT), P0.1/MIP and P0.1 × f/VT. The areas under the curve showed that the tests had not the ability to distinguish between successful and unsuccessful weaning.

Conclusion

Our results show that all the evaluated indexes are poor predictors of weaning outcome in a general intensive care unit population.

Keywords

Mechanical ventilation Weaning Cut-off values Receiver operating characteristic curve Likelihood ratio Weaning predictors 

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Giorgio Conti
    • 1
  • Luca Montini
    • 1
  • Mariano Alberto Pennisi
    • 1
  • Franco Cavaliere
    • 1
  • Andrea Arcangeli
    • 1
  • Maria Grazia Bocci
    • 1
  • Rodolfo Proietti
    • 1
  • Massimo Antonelli
    • 1
  1. 1.Istituto Anestesiologia e Rianimazione, Policlinico Agostino GemelliUniversità Cattolica del Sacro CuoreRomeItaly