ReferencesFrat JP, Coudroy R, Marjanovic N, Thille AW. High-flow nasal oxygen therapy and noninvasive ventilation in the management of acute hypoxemic respiratory failure. Ann Transl Med. 2017 Jul;5(14):297. doi: 10.21037/atm.2017.06.52. Review. PubMed PMID: 28828372; PubMed Central PMCID: PMC5537116.
A study by Frat et al demonstrated that in some populations high-flow oxygen treatment can be much more effective than noninvasive mechanical ventilation. In which patients with acute respiratory insufficiency should we use high-flow oxygen therapy rather than noninvasive ventilation?
Andreas Freitag: As little as 2 or 3 years ago, patients would come in with respiratory failure and they would define them as… “Why are you calling them respiratory failure?” A lot of patients required supplemental oxygen to maintain adequate arterial saturations. Not all of those patients have high partial pressure of carbon dioxide (pCO2) levels, or are hypercarbic. Many of those patients have normal ventilation and normal or near-normal CO2 levels but they have a low saturation. For these patients it is ideal to use Optiflow, or high-flow oxygen, because they do not need bilevel or noninvasive mechanical ventilation necessarily. The study that you just talked about showed exactly that: In the comparison of bilevel mechanical ventilation versus Optiflow, there was no conferred difference or benefit by going to noninvasive mechanical ventilation. By wearing oxygen literally up your nose, the patients are much more comfortable and they function. The patients that have normal or near-normal CO2 levels that are placed on high-flow oxygen—it seems to be appropriate, effective, safe for those patients.
Where do we use noninvasive mechanical ventilation? In patients that truly do have high pCO2 and low oxygen levels. If they really have hypercapnic, hypoxemic respiratory failure, you can try Optiflow, but you are probably going to be a little more successful by using bilevel or noninvasive mechanical ventilation in this regard.