Helmet Noninvasive Ventilation Produces Mixed Results in COVID-19

Study hoping to show reduced need for respiratory support with the approach failed to do so, though it does appear to limit the need for intubation.

In the early days of the COVID-19 pandemic, as many as one in three patients admitted to the hospital with severe disease required respiratory support. Unfortunately, many of those patients succumbed to the virus.

Now, more than a year into the pandemic, treatment with corticosteroids—not to mention vaccination of at least some of the population—has helped reduce the numbers of patients requiring ICU treatment and respiratory support. However, given the high risk for mortality associated with its use in COVID-19, researchers continue to look for alternative approaches, with continuous positive airway pressure (CPAP) or bi‐level positive airway pressure (BiPAP) among those considered.

A study published on March 25 by JAMA Network Open assessed the efficacy of one such approach, helmet noninvasive ventilation, in the management of moderate to severe acute hypoxemic respiratory failure caused by COVID-19 among patients treated in 4 Italian hospital ICUs. Although it offered some benefit, the researchers found that it yielded “no significant difference in the number of days free of respiratory support within 28 days” compared with nasal high-flow oxygen.

“In this study, treatment with helmet noninvasive ventilation did not result in a reduced duration of respiratory support, but was associated with improved oxygenation and dyspnea, reduced rate of endotracheal intubation, and increased days free of invasive ventilation at 28 days from randomization,” wrote the researchers, who did not respond to requests for comment. “These results indicate that noninvasive respiratory support with helmet noninvasive ventilation did not directly affect the disease process and the duration of the need for respiratory support but enabled successful noninvasive management with avoidance of intubation in a greater proportion of patients.”

In theory, helmet noninvasive ventilation has the potential to “deliver longer-term treatments with higher levels of positive end-expiratory pressure, which may be crucial to improve hypoxemia and prevent progression of lung injury during spontaneous breathing,” the researchers said. However, in their study in which 110 patients who were randomized (109 completed the trial), the median days free of respiratory support within 28 days after randomization were 20 in the helmet noninvasive ventilation group versus 18 in the high-flow nasal oxygen group, a difference that is not statistically significant (P=0.26).

Furthermore, of 9 secondary outcomes, there was no significant difference between the 2 approaches in 7 of them. The exceptions? The rate of endotracheal intubation was significantly lower in the helmet noninvasive ventilation group (30%) compared with the high-flow nasal oxygen group (51%; P=0.03). And, the median number of days free of invasive mechanical ventilation within 28 days was significantly higher in the helmet noninvasive ventilation group (28) than in the high-flow nasal oxygen group (25; P=0.04).

Unfortunately, in-hospital mortality was also similar between the 2 groups (24% in the helmet group versus and 25% in the high-flow nasal oxygen group; P>0.99).

“Avoidance of intubation appears of paramount importance to prevent the complications related to invasive mechanical ventilation, sedation, delirium, and paralysis,” the researchers wrote. “Also, successful management of patients with hypoxemia without endotracheal intubation allows more efficient resource allocation in the intensive care unit, especially in the context of the COVID-19 pandemic.”

Still, they added, “high-flow nasal oxygen is recommended as first-line intervention for patients with hypoxemia [though] the data from this trial indicate that an early trial with helmet noninvasive ventilation may possibly benefit patients with most severe oxygenation impairment.”

Which means, for now, viable options for patients with hypoxemia due to COVID-19 remain relatively limited.