Helmet noninvasive ventilation does not increase days free of respiratory support
Among patients with COVID-19 and moderate to severe hypoxemia, there was no significant difference in days free of respiratory support between those who received helmet noninvasive ventilation or high-flow nasal oxygen alone.
“Because high-flow nasal oxygen is simple to use and has clinical and physiological effects, it is recommended as the first-line intervention for respiratory support in patients with hypoxemia and is widely applied in patients with COVID-19,” Domenico Luca Grieco, MD, clinical research fellow in the department of emergency, intensive care medicine and anesthesia at the Catholic University of the Sacred Heart at Fondazione Policlinico University, Rome, and colleagues wrote in JAMA. “Helmet noninvasive ventilation has recently been advocated as an alternative for management of acute hypoxemic respiratory failure, but its use is limited by the lack of evidence regarding its efficacy.”
The multicenter, randomized HENIVOT trial included 109 patients (median age, 65 years; 19% women) with COVID-19 and moderate to severe hypoxemic respiratory failure in four ICUs in Italy from October to December 2020. Participants were randomly assigned to receive continuous treatment with helmet noninvasive ventilation (positive end-expiratory pressure, 10-12 cm H2O; pressure support, 10-12 cm H2O) for at least 48 hours followed by high-flow nasal oxygen (n = 54) or high-flow nasal oxygen alone (60 L/min; n = 55).
The primary outcome was number of days free of respiratory support within 28 days. Secondary outcomes included the proportion of patients requiring endotracheal intubation within 28 days, number of days free of invasive mechanical ventilation at 28 days, number of days free of invasive mechanical ventilation at 60 days, ICU mortality and in-hospital mortality, 28- and 60-day mortality, and length of stay in both the ICU and hospital.
The median number of free of respiratory support within 28 days after enrollment was 20 days in the helmet noninvasive ventilation group compared with 18 days in the high-flow nasal oxygen group (P = .26).
Among the secondary outcomes, only two showed significant differences between both groups. The researchers reported a significantly lower rate of endotracheal intubation in the helmet noninvasive ventilation group compared with the high-flow nasal oxygen group (30% vs. 51%; P = .03). In the helmet noninvasive ventilation group, the median number of days free of invasive mechanical ventilation within 28 days was higher compared with the high-flow nasal oxygen group (28 vs. 25 days; P = .04).
The in-hospital mortality rate between both groups was similar at 24% in the helmet noninvasive ventilation group vs. 25% in the high-flow nasal oxygen group (P > .99).
“To our knowledge, this is the first randomized trial comparing helmet noninvasive ventilation and high-flow nasal oxygen in patients with hypoxemic respiratory failure,” the researchers wrote. “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. 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.”
The researchers concluded that “[f]urther research is warranted to determine effects on other outcomes, including the need for endotracheal intubation.”