To date, the COVID-19 pandemic has affected more than 20 million people worldwide and caused more than 750,000 deaths. Far from having reached control of the disease, most countries are seeing new outbreaks and the main discussion is whether we are looking at isolated peaks of infection or actually at the beginning of a second wave. High-Flow Nasal Cannula therapy has been involved in a war where the main opposing sides have been the increased risk of aerosolization and dissemination of the disease potentially associated with its use, versus the improved clinical control of patients and the reduction of the need for intubation and ICU admission.
In an excellent article by Raoof et al published in the "How do I do it" section of Chest journal (8 August 2020), the authors have reviewed the recommendations of International Societies regarding use of High-Flow Nasal Cannula in COVID-19 Pandemic, highlighting the great controversy that exists on this issue. Some guidelines warn against the routine use of HFNC or any non-invasive, potentially aerosol-generating approach (for example, National Health Care System Guidelines, UK) and others, advocate it as a first-line approach (for example, US Department of Defense COVID management guidelines). But what is really striking is that most of international societies do not comment anything on the use of HFNC in COVID-19, even some relevant scientific societies such as the American College of Chest Physicians, USA. You can see it in the following picture, modified from Raoof paper.
It is quite surprinsigly see how some hospitals strongly discourage the use of non-invasive approaches, favouring early intubation, and others use non-invasive approaches quite frequently, even as the first line option to treat patients with mild to moderate respiratory distress.
Lyons and Callaghan (Anaesthesia 2020, 75, 843–847) tell us in a brilliant Editorial sentences like these: "Clinicians should remain open minded that HFNO may be an appropriate therapy for many patients for whom tracheal intubation has not yet become a necessity but for whom low-flow nasal oxygen or facemask oxygen is not providing adequate respiratory support." "The discordant views expressed by different societies throughout the world reflect uncertainty, but patients with COVID-19 exhibit no geographical discordance in their need for respiratory support." And my favorite: "We must make every practicable effort to protect both ourselves from infection and our patients from dogma." The authors end the article with a last advice: "We must acknowledge the unknowns but prevent them from commandeering the care we provide."
Arulkumaran et al in Lancet Respiratory Medicine (VOLUME 8, ISSUE 6,E45,JUNE 01, 2020) have expressed that "Early intubation of a patient with known or suspected COVID-19 with respiratory distress could result in the intubation and mechanical ventilation of patients who would have otherwise improved on noninvasive respiratory therapies." The main message of these authors is that we have to keep health-care workers safe, thereby facilitating the provision of best patient care.
I like very much the article published by Santos et al in Gac Med Mex (2020;156:258-259) where after an exposure of the benefits and risks of HFNC, they make a request to the health authorities to urgently acquire high flow equipment and to the engineers, companies and research centers to also focus on the production of high-flow cannulas.
As we have expressed in a recent paper published in Med Clin (Barc), the risk of pathogenic agent spread with non invasive respiratory therapies is a problem that has been known for years, not only in the COVID-19 era. However there is a school of thought recommending not to use HFNC in these patients. The application of these criteria has the risk of posing a therapeutic dilemma where clinicians have to choose between administering invasive ventilatory support or giving conventional oxygen therapy to a patient. Patients may not receive adequate treatment until it is time to be intubated and connected to invasive mechanical ventilation, missing the opportunity for non-invasive treatment, and increasing the risk of complications and clinical deterioration. On the other hand, there are patients discharged from critical care units still in need of respiratory support, who are deprived of non-invasive therapies in the hospital ward. Furthermore, non invasive respiratory therapies are the only option in those patients with orders not to intubate and in circumstances in which there is no possibility of admission to critical care units due to overcrowding. Given the risk of pathogen spread, many of these patients are being deprived of them. Non invasive respiratory therapies should not be avoided, but rather applied in strict compliance with 3 requirements: (1) Do not delay intubation when necessary; (2) intensify protective measures, using the appropriate personal protection equipment and minimizing the aerosolization of particles by means of a specific assembly of masks and ventilation circuits; and (3) closely monitoring these patients.
As a final thought, excluding High-Flow Nasal Cannula therapy in the COVID-19 pandemic is a luxury we cannot afford.