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

Objective: To determine whether the bronchodilator effects of albuterol and ipratropium bromide are greater ii updraft nebulization is driven by 80% h elium and 20% oxygen (HELIOX) than if driven by compressed room air (AIR) d uring the treatment of an acute exacerbations of chronic obstructive pulmon ary disease (COPD). Setting: The emergency department of a 750-bed inner-city community hospita l, Methods: Over a 12-month period, a convenience sample of 50 normoxic patien ts presenting with signs and symptoms of an acute exacerbation of COPD were prospectively randomized to receive either HELIOX or AIR as the driving ga s 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 g iven at 20, 40, and 120 mins after randomization using the assigned gas. Sp irometry was obtained while breathing room air before the first treatment ( baseline) and at 1 hr and 2 hrs after the initiation of treatment, The prim ary measure of efficacy was the change in percent of predicted forced expir atory volume in 1 sec (FEV1) over the treatment period. A secondary measure of efficacy was the change in percentage of predicted forced expiratory fl ow after 25% to 75% of vital capacity had been expelled (FEF25-75). Results:Twenty-five patients were randomized to each treatment group. Three patients (1 HELIOX, 2 AIR) were unable to complete the study. The baseline FEV1 was 44% (95% confidence interval, 35% to 52%) of predicted in the HEL IOX 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, Ther e were no significant differences in the change of FEV1 between the two gro ups 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), Conclusion: Use of HELIOX as a driving gas for the updraft nebulization of bronchodilators during the first 2 hrs of treatment of an acute COPD exacer bation failed to improve FEV1 faster than the use of AIR. The faster improv ement in FEF25-75 during the first 2 hrs of treatment was small and of unce rtain clinical significance.