Preventive use of noninvasive ventilation after planned extubation.

Despite a thorough weaning assessment, including a spontaneous breathing trial (SBT), liberation from mechanical ventilation via endotracheal extubation is associated with re-intubation rates of up to 24%.1 Re-intubation, in turn, is associated with an increased risk of mortality, intensive care unit (ICU) stay, need for transfer to longterm care facility,2 and nosocomial pneumonia.3 Avoiding re-intubation is therefore an important goal in weaning mechanically ventilated patients. As part of achieving this goal and improving weaning outcome in general, noninvasive ventilation (NIV) has been increasingly studied and utilized during the last 15 years. This increasingly frequent use is reflected in a recent European survey suggesting that NIV is being utilized by clinicians almost as frequently for weaning as it is for initial respiratory failure due to cardiogenic pulmonary edema.4 The use of NIV during weaning from mechanical ventilation can be divided into 3 types. First, NIV can be used as an adjunct to early separation from invasive mechanical ventilation in patients who have achieved a minimal clinical and respiratory stabilization but who fail an SBT and need only transient low/intermittent ventilatory support. This type of NIV use is supported by several studies that, compared with usual invasive ventilation weaning mostly in COPD patients, have shown that NIV resulted in shorter duration of mechanical ventilation and lower incidence of complications, with no difference in re-intubation rates.5–8 Second, NIV can be used as rescue therapy for patients who develop respiratory distress or failure soon after extubation. Two randomized controlled studies testing this type of NIV application versus usual care in patients with respiratory failure of multiple etiologies showed no difference in re-intubation rates,9,10 and one of them suggested higher ICU mortality in the NIV group, possibly from delaying the necessary re-intubation.9 These findings led to the idea that, by the time post-extubation respiratory failure has developed, it may be too late for the patient to be “rescued” from re-intubation using NIV. Therefore, the third type of NIV use studied in weaning has been its early or preventive use right after planned extubation following tolerance of an SBT. This is applied with the intention of preventing post-extubation respiratory failure, which some patients might develop, and by extension re-intubation, with its associated risks. Several randomized controlled trials have evaluated this type of NIV use (preventive NIV), the focus of this editorial. Nava et al11 randomized 97 patients with at least one risk factor for post-extubation respiratory failure (prior weaning trial failure, congestive heart failure, PaCO2 45 mm Hg after extubation, 1 comorbidity, weak cough, stridor) to 48 hours of preventive NIV versus usual care (without NIV rescue) and showed a significant decrease in re-intubation rate (16% absolute difference) with NIV, but no direct effect on ICU or hospital stay and mortality. Ferrer et al12 randomized 162 patients with at least one of the following different risk factors (age 65, congestive heart failure as cause of respiratory failure, APACHE II 12) to 24 hours of preventive NIV (with additional NIV rescue) versus usual care with NIV rescue, showing a decrease of post-extubation respiratory failure with preventive NIV, but no significant difference in reintubation rate or length of stay. They also noted a lower ICU mortality in the preventive NIV group, but no difference in hospital or 90 day mortality. This same Spanish group13 subsequently performed a similar trial, but now selecting 106 patients who had chronic lung disease ( 70% with COPD) and PaCO2 45 mm Hg at the end of an otherwise successful SBT. Similar to their first study, they showed a decrease in the proportion of patients meeting criteria for post-extubation respiratory failure with preventive NIV, but no significant difference in re-intubation rate. ICU and hospital length of stay and mortality were no different, but an intriguing 90 day mortality advantage for the preventive NIV group was noted.