Clinical Comparison of Two Aerosol Holding Chambers: ACE vs Aerochamber

Abstract

BACKGROUND: Aerosol holding chambers (HCs) have proven to be an effective enhancement to the administration of aerosolized medications by metered-dose in-haler (MDI). Recent bench tests demonstrating different performance characteris-tics among HCs, which have unknown clinical relevance, suggest the need for pa-tient studies to confirm the clinical effectiveness of each new HC-MDI combination. We compared the Aerochamber with the Aerosol Cloud Enhancer (ACE) combined with albuterol MDI in stable asthmatics. METHODS: Ten subjects were selected whose FEV₁ (the volume exhaled in the first second of a forced exhalation) in-creased by at least 15% following an albuterol aerosol. On separate study days, sub-jects withheld asthma medications for 8 hours, then inhaled 2 puffs of albuterol MDI (90 µg/puff) using both HCs. Patients performed FEV₁ before (pre) and at 30, 60, and 120 minutes after (post) albuterol. Pulse, blood pressure, and incidence of side effects were recorded. Change in FEV₁ was expressed using "% possible" FEV₁ [% possible = (pre- post FEV₁)/(predicted - pre FEV₁)]. RESULTS: Mean (SD) % possible at t = 30, 60, and 120 minutes for ACE were 37.7 (10.1), 35.0 (12.6), and 25.7(16.2) and for Aerochamber were 28.1 (14.6), 21.8 (20.3), and 25.4 (27.1). The differences in % possible between ACE and Aerochamber were not statistically significant at any time period (p > 0.05, paired t test). CONCLUSIONS: Our results confirm that the ACE- and Aerochamber-MDI combinations function comparably in adult patients with stable asthma. On average, the difference between HCs was also not clinically important.