key: cord-0917501-9nzq1e2y
authors: Belenguer-Muncharaz, A.; Hernández-Garcés, H.
title: Reply to «Pulmonary toxicity by oxygen and COVID-19»
date: 2022-04-27
journal: Med Intensiva (Engl Ed)
DOI: 10.1016/j.medine.2022.04.005
sha: 74b280f24234e21c0293a99359282f7f8162d11c
doc_id: 917501
cord_uid: 9nzq1e2y

nan

We read with great interest the letter in which the authors talk about the deleterious effect of using a high fraction of inspired oxygen (FiO2) in patients with acute respiratory distress syndrome (ARDS) due pneumonia caused by SARS-CoV-2 where they advocate for the use of continuous positive airway pressure (CPAP) to reduce the high FiO2 used in high-flow nasal oxygen (HFNO) therapy. 1 We agree with the authors when they talk about planning CPAP or non-invasive ventilation (NIV) as an alternative to HFNO. However, clinical practice guidelines say otherwise and they recommend HFNO and choose invasive mechanical ventilation (IMV) in cases of failed HFNO. 2 Based on these recommendations, 2 a Spanish multicenter registry (n░=░876 patients) showed a wide use of HFNO (49%) vs NIV, and CPAP (<░5% in both modalities). We should mention the high rate of failure in the HFNO group (60%) with mortality rates > 30% in patients who required intubation. 3 The efficacy of NIV in SARS-CoV-2-induced pneumonia was demonstrated in an Italian multicenter registry (N░=░110 patients) that compared the NIV-helmet to HFNO. Although the registry primary endpoint-ventilation-free days (20 days vs 18 days, P░=░.26)-was not achieved the NIV group had lower rates of intubation on day 28 vs the HFNO group [28% vs 51%; OR, 0.37 (0.17-0.82), P░=░.02]. At the same time, the NIV-helmet had better oxygenation, and less dyspnea compared to the HFNO group. 4 Consistent with one of the arguments that support the use of HFNO, 2 the patients' tolerance was higher with HFNO compared to NIV 4 . Similarly, in our series of 27 hypoxemic patients due to SARS-CoV-2-induced pneumonia, NIV was used as the first-line therapy in 21 patients (80.8%) basically with NIV specific ventilators in CPAP mode. CPAP failed in 10 patients (48%) with an associated mortality rate of 50%. No health personnel became infected in relation to the NIV as opposed to what has been reported in the clinical practice guidelines. 2 Therefore, based on these guidelines, 2 we believe that the HFNO plays a key role in the early ventilatory therapy of hypoxemic patients. Unfortunately, the rate of failure in hypoxemic patients is high, 3 which may have overestimated the true efficacy of HFNO in advanced stages of ARDS. Like the authors say, a high FiO2 in HFNO added to the pulmonary damage caused by the virus worsens ARDS, and eventually leads to IMV. 1 On the contrary, results from the latest clinical trials, 3 and observational studies 4 pave the way for the safe use of NIV in its different modes (CPAP or NIV) by applying positive end-expiratory pressure (PEEP) that recruits the damaged lung, which allows reaching a non-detrimental FiO2 1 while avoiding IMV and its deleterious effect. 3, 5 

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