Authors: Stéphan F et al., JAMA 2015 Jun 16; 313:2331
In one trial, intubation rates were similar to those of noninvasive positive pressure ventilation, and 90-day mortality was lower.
Use of noninvasive positive pressure ventilation (NPPV) in patients with chronic obstructive pulmonary disease exacerbations and cardiogenic pulmonary edema is well established, but its value in treating patients with hypoxemic respiratory failure is unclear. High-flow oxygen delivered by nasal cannula might be an alternative to NPPV in these patients. Investigators explored this question in two multicenter European studies.
In one trial, 310 patients (>60% with community-acquired pneumonia; none with hypercarbia) with hypoxemic respiratory failure were randomized to high-flow oxygen, standard oxygen delivery, or NPPV. Standardized criteria for intubation were used, including relatively conservative thresholds for pH (<7.35) and oxygen saturation (<90% for >5 minutes). Intubation rates did not differ significantly among the three groups but trended lower in the high-flow–oxygen group. This group also had a significantly lower mortality at 90 days, more ventilator-free days, and less respiratory discomfort.
In the other randomized trial, researchers compared NPPV with high-flow oxygen in 830 patients with hypoxemia after cardiothoracic surgery; reintubation rates were similar (13.7% vs. 14%), as was intensive care unit mortality (5.5% vs. 6.8%). Criteria for intubation were slightly more liberal in this study.
These results support use of high-flow oxygen in a select population of patients with acute hypoxemic respiratory failure and postoperative hypoxemia. I believe that high-flow oxygen should be the first-line therapy in these patients. Importantly, no patient in these studies had hypercarbia. Ventilatory support (i.e., NPPV) remains the superior treatment in patients with hypercarbic respiratory failure due to chronic obstructive pulmonary disease. This distinction in gas exchange abnormality (hypoxemia vs. hypercarbia) is essential in treatment decision-making.