Randomized trial of the use of heliox as a driving gas for updraft nebulization of bronchodilators in the emergent treatment of acute exacerbations of chronic obstructive pulmonary disease

Abstract

To determine whether the bronchodilator effects of albuterol and ipratropium bromide are greater if updraft nebulization is driven by 80% helium and 20% oxygen (HELIOX) than if driven by compressed room air (AIR) during the treatment of an acute exacerbations of chronic obstructive pulmonary disease (COPD). The emergency department of a 750-bed inner-city community hospital. Over a 12-month period, a convenience sample of 50 normoxic patients presenting with signs and symptoms of an acute exacerbation of COPD were prospectively randomized to receive either HELIOX or AIR as the driving gas for updraft nebulization of a mixture of albuterol 2.5 mg and ipratropium bromide 0.5 mg. Additional aerosol treatments with albuterol 2.5 mg were given at 20, 40, and 120 mins after randomization using the assigned gas. Spirometry was obtained while breathing room air before the first treatment (baseline) and at 1 hr and 2 hrs after the initiation of treatment. The primary measure of efficacy was the change in percent of predicted forced expiratory volume in 1 sec (Fev1) over the treatment period. A secondary measure of efficacy was the change in percentage of predicted forced expiratory flow after 25% to 75% of vital capacity had been expelled (Fef25–75). Twenty-five patients were randomized to each treatment group. Three patients (1 HELIOX, 2 AIR) were unable to complete the study. The baseline Fev1was 44% (95% confidence interval, 35% to 52%) of predicted in the HELIOX group and 39 (31% to 46%) of predicted in the AIR group. There were no adverse outcomes observed in either the HELIOX group or the AIR group. There were no significant differences in the change of Fev1 between the two groups by either the 1 hr or 2 hr time point (1 hr, HELIOX + 10% [7% to 13%], AIR + 9% [5% to 13%]; 2 hr HELIOX + 10% [6% to 15%], AIR + 10% [6% to 14%]). The improvement in Fef25–75 was significantly greater in the HELIOX group than in the AIR group at both the 1 hr time point (HELIOX + 14% [7% to 22%] vs. AIR + 7% [3% to 10%], p = .05) and at the 2 hr time point (HELIOX + 15% [8% to 21%] vs. AIR + 7% [4% to 11%], p = .05). Use of HELIOX as a driving gas for the updraft nebulization of bronchodilators during the first 2 hrs of treatment of an acute COPD exacerbation failed to improve Fev1 faster than the use of AIR. The faster improvement in Fef25–75 during the first 2 hrs of treatment was small and of uncertain clinical significance.