NT-proBNP levels at spontaneous breathing trial help in the prediction of post-extubation respiratory distress.

PURPOSE

To evaluate and compare the performance of NT-proBNP levels, plasma protein concentration, hematocrit, and fluid balance for the preceding 24 h in predicting the outcome of the two steps of weaning: (1) spontaneous breathing trial (SBT), (2) extubation.

METHODS

This was a prospective observational study of 143 patients who were mechanically ventilated for more than 48 h (55% COPD) and were ready to wean. They underwent an SBT and were extubated when they passed the trial. Immediately before the SBT, we measured the evaluated diagnosis tools.

RESULTS

Of 143 patients, 80 (56%) passed the SBT and were extubated. Of these, two were reintubated for laryngeal dyspnea, 57 had no respiratory problem during the next 48 h, and 21 developed post-extubation respiratory distress (26%). Rescue noninvasive ventilation (NIV) prevented reintubation in 15 (71%). None of the tested diagnosis tools predicted the outcome of the SBT. Patients who developed post-extubation respiratory distress were older, had lower values of plasma protein concentration and higher values of NT-proBNP than those who did not. Only NT-proBNP was an independent predictor of the occurrence of post-extubation respiratory distress (OR 1.2; 95% CI 1.09-1.4; p = 0.003); the area under the ROC curve for NT-proBNP to predict post-extubation respiratory distress was 0.78 (95% CI 0.67-0.89; p = 0.0001). NT-proBNP was more accurate to rule out (negative likelihood ratio 0.09 for a cutoff of no greater than 1,000 pg/ml) than to rule in the risk of post-extubation respiratory distress (positive likelihood ratio 3.45 for a cutoff of at least 2,000 pg/ml).

CONCLUSION

NT-proBNP levels at SBT help in the prediction of post-extubation respiratory distress and could identify the subgroup of extubated patients requiring close observation and/or prophylactic NIV.