The use of high-flow nasal oxygen vs helmet noninvasive ventilation did not significantly vary for the treatment of critically ill patients with severe hypoxemic respiratory failure as a result of COVID-19 when comparing the number of days free of respiratory support within 28 days, according to study results published in JAMA.

Currently, there is still debate surrounding the role of noninvasive respiratory support in patients with acute hypoxemic respiratory failure, and high-flow nasal oxygen remains the initial treatment recommendation for this patient population.

A team of investigators conducted the Helmet Noninvasive Ventilation Versus High-Flow Oxygen Therapy in Acute Failure Trial (HENIVOT; Identifier: NCT04502576), an open-label, multicenter analysis, randomized clinical trial, to determine whether helmet noninvasive ventilation could reduce the number of days a patient with COVID-19 could need respiratory support compared with high-flow nasal oxygen alone.  

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The study was conducted at 4 intensive care units (ICUs) in Italy from October to December 2020. The end of follow-up was February 11, 2021. The primary outcome of the study was the number of respiratory support-free days within 28 days of enrollment. Secondary outcomes included the number of patients who required endotracheal intubation within 28 days of enrollment, the number of days free from invasive mechanical ventilation at day 28 and day 60, in-ICU and in-hospital mortality rates, 28-day and 60-day mortality rates, length of stay in ICU, and length of stay in hospital.

A total of 109 patients (median age, 65 years; 19% women) were randomly assigned 1:1 to receive either continuous treatment with helmet noninvasive ventilation (n=54) or high-flow nasal oxygen (n=55) for at least 48 hours. By the end of the study, 53 patients in the helmet noninvasive group and 54 patients in the high-flow nasal oxygen group had completed the study protocol.

Following 48 hours of uninterrupted noninvasive ventilation, participants underwent either continuous Venturi mask or high-flow nasal oxygen (attending physician’s choice). If patients in the high-flow group experienced respiratory distress and hypoxemia, high-flow nasal oxygen could be resumed at any time; however, the use of noninvasive ventilation was not permitted for individuals enrolled in this cohort.

Within 28 days of enrollment, the median number of days free of respiratory support were 20 days and 18 days in the noninvasive helmet and high-flow nasal oxygen groups, respectively (P =.26).

Although the majority of secondary outcomes were not statistically significant, the rate of endotracheal intubation was significantly lower in the noninvasive helmet group compared with the high-flow nasal oxygen group (30% vs 51%; absolute risk reduction, 21%; unadjusted odds ratio, 0.41; P =.03). Within 28 days of enrollment, the number of days free of invasive ventilation was also significantly greater in the noninvasive helmet group compared with the high-flow nasal oxygen group (mean difference, 3 days; P =.04).

Some study limitations included underpowering the study to detect small differences between groups for the primary endpoint, variation in helmet noninvasive ventilation technique settings, nonstandardization of awake prone positioning of patients, and the inability to generalize hypoxemic respiratory failure findings because of the COVID-19 positive status of all enrolled patients.

“[R]ecent guidelines have been unable to provide conclusive recommendations on the use of face-mask noninvasive ventilation in patients with hypoxemia, while the use of high-flow nasal oxygen was encouraged,” the study authors noted.

“Further research is warranted to determine effects on other outcomes, including the need for endotracheal intubation,” concluded the investigators.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original article for a full list of authors’ disclosures.


Grieco DL, Menga LS, Cesarano M, et al; for the COVID-19 ICU Gemelli Study Group. Effect of helmet noninvasive ventilation vs high-flow nasal oxygen on days free of respiratory support in patients with COVID-19 and moderate to severe hypoxemic respiratory failure. JAMA. Published online March 25, 2021. doi:10.1001/jama.2021.4682