The use of noninvasive ventilation (NIV) techniques, that is, continuous positive airway pressure (CPAP) in post-extubation respiratory failure has been described in the literature. Several randomized controlled trials (RCT) have shown mixed results. A randomized multinational, multi-institutional trial in 2004 evaluated the effect of NIV on mortality in patients who were electively extubated after 48 h of mechanical ventilation and developed respiratory failure in the subsequent 48-h post-intubation period [2]. Patients were randomized to standard medical therapy (supplemental oxygen, bronchodilators, other therapy as directed by an attending physician) or to NIV via full-face mask. The study found that, in an unselected population of ICU patients, NIV did not prevent the need for reintubation and showed a trend toward higher mortality when NIV was used [2]. The higher rate of mortality in the NIV group was felt to be the result of the longer interval to re-intubation compared with the standard therapy group. An earlier RCT with similar design compared NIV with supplemental oxygen in patients with a history of cardiac or pulmonary disease who developed respiratory distress within 48 h of being extubated. The study concluded that there was no difference in the rate of reintubation, mortality, duration of mechanical ventilation, or length of ICU stay [3].

Subsequent RCTs identified patients who were deemed to be high risk for extubation where NIV showed a benefit; however, this was in a specific subset of patients with chronic obstructive pulmonary disease, congestive heart failure, and/or hypercapnia [4]. A meta-analysis in 2007 concluded that NIV should be used judiciously if at all in patients with post-extubation respiratory failure [5].

The issue with extrapolating these data to trauma patients is that the study groups in the previously referenced studies were a heterogeneous population. Trauma patients made up only a small percentage of the total study population, and in some studies were not included at all [4].

The trauma literature is less robust when looking at the use of NIV. In 2002, the British Thoracic Society Standards of Care Committee gave only a grade C (low) recommendation on the use of NIV for patients with chest wall trauma who remain hypoxic despite the use of high-flow oxygen and adequate regional anesthesia, because of lack of evidence [6]. However, since then there have been several studies looking specifically at the use of NIV in patients with chest injuries.

A prospective randomized controlled trial in 2010 looked at the use of NIV in chest trauma-related hypoxia [7]. Adult patients over a 3-year period who sustained severe thoracic trauma were not intubated and had persistent hypoxemic respiratory failure (defined as a PaO₂/FiO₂ ratio <200 mmHg while on high-flow oxygen). Patients were randomized to receive either NIV or remain on high-flow oxygen via mask. The trial was stopped prematurely after 50 patients were enrolled because an interim analysis revealed that the NIV group showed a significantly reduced intubation rate (10 % in the NIV group vs 40 % in the oxygen only group) [7]. There was no mortality difference between the two groups. The authors concluded that early and continuous application of NIV in patients with thoracic trauma helped reduced the need for intubation in this subset of trauma patients [7].