Noninvasive respiratory support for acute respiratory failure due to COVID-19

Abstract

Purpose of review: Noninvasive respiratory support has been widely applied during the COVID-19 pandemic. We provide a narrative review on the benefits and possible harms of noninvasive respiratory support for COVID-19 respiratory failure.

Recent findings: Maintenance of spontaneous breathing by means of noninvasive respiratory support in hypoxemic patients with vigorous spontaneous effort carries the risk of patient self-induced lung injury: the benefit of averting intubation in successful patients should be balanced with the harms of a worse outcome in patients who are intubated after failing a trial of noninvasive support.The risk of noninvasive treatment failure is greater in patients with the most severe oxygenation impairment (PaO2/FiO2 < 200 mmHg).High-flow nasal oxygen (HFNO) is the most widely applied intervention in COVID-19 patients with hypoxemic respiratory failure. Also, noninvasive ventilation (NIV) and continuous positive airway pressure delivered with different interfaces have been used with variable success rates. A single randomized trial showed lower need for intubation in patients receiving helmet NIV with specific settings, compared to HFNO alone.Prone positioning is recommended for moderate-to-severe acute respiratory distress syndrome patients on invasive ventilation. Awake prone position has been frequently applied in COVID-19 patients: one randomized trial showed improved oxygenation and lower intubation rate in patients receiving 6-h sessions of awake prone positioning, as compared to conventional management.

Summary: Noninvasive respiratory support and awake prone position are tools possibly capable of averting endotracheal intubation in COVID-19 patients; carefully monitoring during any treatment is warranted to avoid delays in endotracheal intubation, especially in patients with PaO2/FiO2 < 200 mmHg.

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FIGURE 1

Panel reporting the failure rate [95% CI] of patients with hypoxemic respiratory failure treated with noninvasive respiratory support. Failure rate was defined as occurrence of endotracheal intubation or death. Only the patients without limitation of treatment were considered for the figure. Except from the bottom – right figure, nonrandomized studies including awake prone position were excluded from the figure, due to the possible selection bias of patients treated with conventional therapy. The studies with the bigger sample size are displayed at the top of the figure. (a) Forest plot of patients treated with HFNO in the supine position. (b) Forest plot of patients treated with NIV as first line of therapy. (c) Forest plot of patients treated with CPAP as first line of therapy. (d) Forest plot of patients treated with awake prone position, regardless of the kind of noninvasive respiratory support used. ^∗It was not possible to differentiate between CPAP and NIV that were both considered as noninvasive respiratory support. CPAP, continuous positive end-expiratory pressure; HFNO, high-flow nasal oxygen; NIV, noninvasive ventilation.