For hospitalists and residents across the country, this is an all too familiar scenario: a 60-year-old man is admitted to the hospital with pneumonia. Unfortunately, his course is complicated by acute hypoxemic respiratory failure secondary to the pneumonia, and he is transferred to the ICU. Physicians would like to avoid intubation if possible due to its invasiveness and attendant adverse consequences, but it is clear, something more must be done to support this patient.
What about noninvasive ventilation (NIV) delivered in the form of positive pressure via a facemask? It has been shown to be an effective therapy for patients with acute exacerbations of a chronic lung condition, like COPD, and cardiogenic pulmonary edema. By extension, it has been assumed that it would benefit others with acute respiratory failure, but it actually has not been tested in patients with de novo non-hypercapnic respiratory failure. On the other hand, high-flow oxygen therapy, in which oxygen is delivered through nasal cannula at high rates, has recently emerged as perhaps an alternative to NIV in the latter setting.
To address this issue, Frat et al. performed a prospective, multicenter randomized controlled trial to assess the effectiveness of NIV vs. high-flow oxygen in ICU patients with de novo non-hypercapnic respiratory failure. Just over 300 patients participated in the trial, and they were approximately evenly randomized to one of three therapies: standard oxygen, high-flow oxygen, or NIV. There was no significant difference between the three groups in terms of the primary outcome of intubation rate at day 28, although the rate in patients treated with high-flow oxygen was lower. However, high-flow oxygen did lead to a statistically significant increase in ventilator free days and decrease in 90-day mortality as compared to standard therapy or NIV. Furthermore, high-flow oxygen therapy improved patient comfort over the other two therapies. However, all of these were secondary outcomes.
While this trial did not find a significant difference in terms of the primary outcome, the decreased 90-day mortality rate with high-flow oxygen therapy is an interesting and promising finding. Based on these data, Michael Matthay, MD, recommends in an accompanying editorial that high-flow oxygen treatment be considered for patients with non-hypercapnic, hypoxemic respiratory failure in settings where appropriate monitoring is available. However, he notes that more trials are needed. As for our elderly patients presenting with new respiratory failure from pneumonia like above, it may just be better to reach for a high-flow nasal cannula rather than the facemask.