Extubation failure after successful spontaneous breathing trial: prediction is still a challenge!

The timing of extubation is crucial during critical illness, since either delayed or premature discontinuation from mechanical ventilation is associated with an increased risk of morbidity and mortality,1 and the literature suggests that an early identification of patients who are able to breathe spontaneously reduces the duration of mechanical ventilation and complication rate.1 However, even when a spontaneous breathing trial (SBT), with either a T-piece or low-pressure support, has been successfully passed, failure of planned extubation occurs in approximately 15% of patients.2 Patients requiring reintubation have a high mortality rate and longer ICU stay,1,2 likely due to a worse severity of illness at extubation, or to clinical deterioration resulting from extubation failure, reintubation, and/or prolongation of mechanical ventilation. The SBT predicts the patient’s tolerance of unassisted breathing, but it does not challenge the patient on the ability to tolerate endotracheal tube removal.3 Factors associated with extubation failure include older age,2 worse severity of illness,2 pneumonia as the reason to initiate mechanical ventilation,4 inadequate cough,5 excessive respiratory secretions,6,7 upper-airway obstruction,3 and hypercapnia.8,9 The evidence is more controversial concerning the importance of neurological impairment, since some studies found it a risk factor,8 whereas others did not find an association between decreased level of consciousness and extubation failure.1,2 Another important and common risk factor is cardiac dysfunction,3 the prompt diagnosis of which allows effective treatment. Chien et al10 found that a 20% variation in plasma brain natriuretic peptide from the pre-SBT baseline improved the predictive value of the SBT for successful extubation from 80% to 97%.