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Among patients with coronavirus disease 2019 (COVID-19) and moderate-to-severe hypoxemia, treatment with helmet noninvasive ventilation, compared with high-flow nasal oxygen, resulted in no significant difference in the number of days free of respiratory support within 28 days, according to a study published in JAMA.
Between October 13 and December 13, 2020, researchers led by Domenico Luca Grieco, MD, Fondazione Policlinico Universitario AGemelli IRCCS, Rome, Italy, conducted a randomised clinical trial in 4 intensive care units (ICUs) in Italy which included 109 patients (median age, 65 years [interquartile range {IQR}, 55-70]) with COVID-19 and moderate-to-severe hypoxemic respiratory failure (ratio of partial pressure of arterial oxygen to fraction of inspired oxygen [PaO2/FiO2] ≤200). While receiving oxygen therapy with a Venturi mask before randomisation, the median PaO2/FiO2 ratio and the median respiratory rate of the patients were 102 (IQR, 82-125) and 28 breaths/min (IQR, 24-32), respectively.
Patients 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 eventually followed by high-flow nasal oxygen (n = 54) or high-flow oxygen alone (60 L/min) (n = 55). A 60-day follow up was completed on February 11, 2021.
The primary outcome was the number of days free of respiratory support within 28 days after enrollment. Secondary outcomes included the proportion of patients who required endotracheal intubation within 28 days from study enrollment, the number of days free of invasive mechanical ventilation at day 28, the number of days free of invasive mechanical ventilation at day 60, in-ICU mortality, in-hospital mortality, 28-day mortality, 60-day mortality, ICU length of stay, and hospital length of stay.
Study data revealed that the median days free of respiratory support within 28 days after randomisation were 20 (IQR, 0-25) in the helmet group and 18 (IQR, 0-22) in the high-flow nasal oxygen group, a difference that was not statistically significant (P = 0.26).
Meanwhile, of 9 prespecified secondary outcomes reported, 7 showed no significant difference.
Nonetheless, the researchers found that the rate of endotracheal intubation was significantly lower in the helmet group compared with the high-flow nasal oxygen group (30% vs 51%, P = 0.03). In addition, patients in the helmet group had a significantly higher median number of days free of invasive mechanical ventilation within 28 days than those in the high-flow nasal oxygen group (28 [IQR, 13-28] vs 25 [IQR 4-28], P = 0.04).
On the other hand, over the initial 48 hours of treatment, an improvement in oxygenation (mean PaO2/FiO2,188 vs 138, P < 0.001) and dyspnea, rated on a visual analog scale (1.9 vs 2.5, P = 0.003) were observed in the helmet group compared with the high-flow nasal oxygen group.
“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 randomisation,” the authors noted. “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 results largely confirmed the data of a recent systematic meta-analysis on acute hypoxemic respiratory failure from heterogeneous causes that suggested a reduction in the intubation rate with helmet noninvasive ventilation when compared with high-flow nasal oxygen,” the authors wrote. “Avoidance of intubation appears of paramount importance to prevent the complications related to invasive mechanical ventilation, sedation, delirium, and paralysis.”
“The data from this trial indicate that an early trial with helmet noninvasive ventilation may possibly benefit patients with most severe oxygenation impairment,” the authors added.