Study objective: To compare the effectiveness of a helium-oxygen mixture with that of oxygen alone as an aerosolizing gas for beta-agonist therapy in patients with mild to moderate exacerbation of asthma.
Methods: A prospective, single-blinded study was performed in an urban teaching hospital over a period of 5 months. A convenience sample of 205 patients with mild to moderate exacerbation of asthma were enrolled. The participants were randomly assigned to 1 of 2 groups. The first group received 3 doses of albuterol, 5.0 mg aerosolized in 10 L/min of oxygen, 15 minutes apart. The second group received 3 doses of albuterol, 5.0 mg aerosolized in 10 L/min of a 70:30 helium-oxygen mixture (heliox), 15 minutes apart. Peak expiratory flow rate (PEFR), forced vital capacity (FVC), and forced expiratory volume in 1 second (FEV1 ) were measured before and after each treatment. Only PEFR and FEV1 were used in data analysis.
Results: Although both the heliox and the oxygen group showed significant improvement in PEFR from baseline after 45 minutes (72% and 70%, respectively), the difference between the 2 groups was clinically and statistically insignificant (P =.56). Similar findings were observed for FEV1. There was no difference in rate of admission or rate of complications between the 2 groups.
Conclusion: Despite its ability to decrease the turbulent flow in airways and to reach distal pulmonary tissues, heliox had no clinically significant advantage over standard therapy in the treatment of mild to moderate asthma. Further large-scale studies are necessary to determine the clinical efficacy of heliox in this setting.