Written by Kevin Liu
Spoon Feed
In non-hypercapnic acute hypoxemic respiratory failure, high-flow nasal cannula showed similar intubation rates to standard oxygen or noninvasive ventilation but significantly reduced 90-day mortality and increased ventilator-free days.
Stop and smell the FLORALIs
The FLORALI trial was the first high-quality multicenter randomized trial conducted that introduced high-flow nasal cannula (HFNC). It added to a growing body of literature that demonstrated noninvasive positive-pressure ventilation or NIPPV (i.e. nasal cannula, non-rebreather masks, CPAP, or BiPAP) reduced intubation rates and mortality in specific patient subsets, most notably COPD exacerbations and cardiogenic pulmonary edema at the time of the trial in 2015.
This trial showed the benefits of HFNC in the treatment of acute non-hypercapnic hypoxemic respiratory failure by significantly lowering total intubated days and 90-day mortality. Patients in this study were included if they had a new oxygen requirement with a respiratory rate greater than 25, PaO2:FiO2 ≤300 mmHg, PaCO2≤45 mmHg, and had no clinical history of chronic respiratory failure, neutropenia, contraindication for NIPPV, or hemodynamic instability.
Following this trial, attempts were made to test its generalizability in different populations. Most notably, the largest RCT looking at immunocompromised patients, HIGH trial, did not demonstrate a mortality benefit for HFNC v.s. standard oxygen supplementation in this population. A meta-analysis of RCTs using non-invasive oxygenation strategies showed reductions in mortality were seen almost exclusively in trials with immunocompetent hosts being treated for severe pneumonia as the primary disease.
How does this change my practice?
HFNC hit primetime during the COVID-19 pandemic in 2020, when patients with acute respiratory distress syndrome (ARDS) due to severe pneumonia had a significantly lower mortality rate compared to all other modalities. For immunocompetent patients without hypercapnia, HFNC is now standard therapy.
Editor’s note: Our IM/PC team wanted to cover some of the landmark studies that have shaped internal medicine and primary care over the past decades. This is the first installment! ~Clay Smith
Source
High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure. N Engl J Med. 2015 Jun 4;372(23):2185-96. doi: 10.1056/NEJMoa1503326. Epub 2015 May 17. PMID: 25981908
