Wednesday May 14, 2008
BNP to predict weaning from ventilator?

Very interesting observation !

Introduction: Despite the use of spontaneous breathing trial (SBT), predicting weaning success remains a major clinical challenge. Because cardiovascular dysfunction could be a major underlying mechanism of weaning failure, role of the levels of B-type natriuretic peptide (BNP), a marker for cardiovascular function, was evaluated in patients who passed a 2 hour SBT.

Design, Setting, and Patients: It was a 3 step study, First: 52 patients recovering from acute respiratory failure were enrolled as the testing group to determine the predictive value of BNP. Second: The predictive value of BNP was validated in a second independent cohort of 49 patients. Third: Both groups of patients were combined to conduct the final analysis.


Measurements and Results:

In the testing group of 52 patients, 41 passed SBT and were extubated. Of these patients, 33 patients (80%) were extubated successfully (extubation success) while eight patients (20%) were reintubated within 48 hrs (extubation failure). There were no differences in the baseline BNP levels, but the extubation failure group had significantly greater increases in BNP at the end of SBT than the extubation success groups

An increase of BNP less than 20% during SBT had the best combination of sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy for predicting extubation success (91%, 88%, 97%, 70%, and 91%).

Combining BNP with SBT as extubation criteria increased the extubation success rate to 95% from 78% using SBT alone (p = .035).


Conclusion: Measuring the percentage change in the BNP level during a SBT may help improve the predictive value of SBT on weaning outcome.



Reference: click to get abstract

Changes in B-type natriuretic peptide improve weaning outcome predicted by spontaneous breathing trial - Critical Care Medicine. 36(5):1421-1426, May 2008.