The purpose of this study was to evaluate the efficacy of
heliox-driven continuous
nebulizers in the management of moderate to severe
asthma exacerbations in the Emergency Department (ED). The trial was a prospective, randomized, double-blind, controlled trial in a university Emergency Department (volume 65,000 patients/year) of patients 18-55 years of age with acute
asthma exacerbations. Patients were placed on continuous
nebulizers driven by 70:30
heliox or air with 30% O(2). Respiratory rate, peak expiratory flow rate (PEFR), forced expiratory volume at 1 s (FEV1), and Borg
dyspnea scale were measured at 0 and 2 h. Disposition and patient satisfaction were also assessed. A total of 36 patients completed the study (18
heliox, 18 air). There was no difference between groups in baseline variables. There was significant interval improvement within both groups at 2 h in PEFR, FEV1, Borg, and respiratory rate. There was no significant difference between
heliox 70:30 and air/
oxygen in PEFR [mean between-group improvement difference 17 liters/min, 95% confidence interval (CI) -20-51], FEV1 (0.03 liters/sec, 95% CI -0.22-0.30), or respiratory rate (mean between-group improvement difference 0.5, 95% CI -2.7-3.8). There was a significant improvement in the patients' perceived
dyspnea as measured by the Borg
dyspnea scale at 2 h in the
heliox group (1.6, 95% CI 0.3-3.0). In this trial of patients with moderate-severe
asthma exacerbation,
heliox-driven continuous
nebulizers failed to demonstrate an improvement in respiratory rate, oxygen saturation, PEFR, or FEV1 at 2 h. However, there was a significant improvement in the patients' perceived
dyspnea on
heliox over air/
oxygen measured by the Borg
dyspnea scale.