Nasal High‐flow Oxygen Versus Conventional Oxygen Therapy for Acute Severe Asthma Patients: A Pilot Randomized Controlled Trial

Abstract

Background: Nasal high flow (NHF) has demonstrated efficacy in relieving dyspnea in various patients with hypoxemic and hypercapnic respiratory failure. It may also reduce dyspnea in patients with acute severe asthma in the emergency department (ED). The aim of the study was to compare the efficacy of NHF with conventional oxygen therapy (COT) in improving dyspnea in acute severe asthma patients with hypoxemia in the ED.Methods: This pilot nonblinded randomized controlled trial was conducted involving 37 patients aged ≥ 18 years with acute severe asthma and hypoxemia in the ED of Siriraj Hospital, Bangkok, Thailand (TCTR20180926003). The participants were randomly allocated to receive either COT (n = 18) or NHF (n = 19) for 120 minutes. The primary outcome was comparing the intervention effects on the patients' degree of dyspnea measured using the modified Borg scale (MBS). The secondary outcomes were comparing the interventions based on the numeric rating scale (NRS) of dyspnea, the dyspnea scale assessing accessory muscle use, vital signs, and blood gas results. Results:The intention-to-treat analysis included 37 patients (COT group n = 18 and NHF group n = 19). The baseline mean MBS was 7.8 in both groups. At 120 minutes, the mean (AESD) MBSs in patients receiving COT and NHF were 3.3 (AE2.5) and 1.4 (AE2.5), respectively (mean difference = 1.9 [95% CI = 0.2 to 3.8], p = 0.043). The trends in NRS and dyspnea score results were similar to those of MBS. Respiratory rates were lower with NHF (mean difference = 4.7 [95% CI = 1.5 to 7.8], p = 0.001). No between-or within-group differences in blood gas results were found. Conclusion:Nasal high flow reduced the severity of dyspnea and respiratory rate in hypoxemic patients with acute severe asthma in the ED.A sthma is a chronic inflammatory airway disease characterized by airway hyperresponsiveness and often reversible airflow obstruction. 1 It is one of the most common airway diseases in both children and

The Efficacy of High-flow Oxygen Versus Conventional Oxygen for Asthma Control: A Meta-analysis of Randomized Controlled Studies

“…152 potentially relevant articles are identi ed initially. Finally, four RCTs are included in the meta-analysis [12,18,19,26].…”

“…High-ow oxygen ranges from 2 to 60 L/min. one RCT involves children with asthma [26], while the other three RCTs involve adult patients [12,18,19].…”

“…Two studies report dyspnea score [12,19], two studies report dyspnea score PaCO2, PaO2 and intubation [12,18], and three studies report dyspnea score hospital length of stay [12,18,26]. Jadad scores of the four included studies vary from 3 to 4, and all four studies have high-quality based on the quality assessment.…”

“…The exacerbation of asthma results in an acute obstruction of expiratory air ow due to airway in ammation, bronchospasm, and hypersecretion, which needs the increased work of breathing [10,11]. If emergent and effective treatment is conducted for asthma exacerbation, the respiratory muscles may fatigue, accompanied by hypercapnia, severe hypoxemia, and consequently respiratory failure [12].…”

“…Current evidence is insu cient for routine clinical use of high-ow oxygen therapy for asthmatic patients. Recently, several studies have investigated the e cacy of high-ow oxygen versus conventional oxygen therapy for these patients, but the results are con icting [12,18,19]. This systematic review and meta-analysis of RCTs aims to assess the e cacy of high-ow oxygen versus conventional oxygen therapy in asthmatic patients.…”