The Science Journal of the American Association for Respiratory Care

2007 OPEN FORUM Abstracts

A PERFORMANCE AND COST COMPARISON OF FOUR VALVED HOLDING CHAMBERS DURING SIMULATED UNCOORDINATED BREATHING

C. D. Okeson1, P. McGowen1

Background: Valved holding chambers (VHCs) are widely prescribed to patients for whom coordinated breathing is difficult. For such patients, there may be a brief time lapse between metered-dose inhaler (MDI) actuation into the VHC and inhalation, during which time drug can deposit and be lost inside the VHC chamber. To simulate such uncoordinated breathing, our study compared the drug mass delivered per MDI actuation after a two-second delay by four VHCs: one collapsible device made from paperboard (LiteAireTM, Thayer Medical, Tucson, AZ), and three devices made from rigid polymer (AeroChamber Max® and AeroChamber Plus®, Monaghan Medical Corp., Syracuse, NY; and OptiChamber Advantage®, Respironics, Cedar Grove, NJ).

Method
: Five of each of the four VHCs (n=5) were evaluated using a USP throat model attached via 22 mm tubing to a Harvard Apparatus (Holliston, MA) large animal ventilator simulating tidal breathing of 750 mL at 12 breaths/minute and 1:1 I:E. Eight actuations of albuterol sulfate were delivered to each VHC from a pre-primed and shaken MDI canister. After each MDI actuation there was a two-second pause prior to inhalation. Drug delivered through each VHC was captured on a filter connected just downstream of the throat model, eluted by rinsing twice with an 18 mL aliquot of 1 M KCl buffer, and quantified via ultraviolet spectroscopy at 276 nm. Drug mass delivered per MDI actuation was calculated as the mean of five unit results for each VHC tested. Device performances were compared via two-tailed T-tests with p < 0.05 indicating a significant difference between VHCs.

Results: The results are summarized in the table below. The drug mass per MDI dose delivered by the AeroChamber Max (67 µg/dose) was significantly larger than the LiteAire (55 μg/dose), the OptiChamber Advantage (52 μg/dose), and the AeroChamber Plus (48 μg/dose), which were not significantly different from each other. When device cost was factored in, the LiteAire was the most efficient, costing $0.05 per μg of drug delivered, compared to $0.16 for the AeroChamber Max, $0.20 for the OptiChamber Advantage, and $0.21 for the AeroChamber Plus.

Conclusion: Under the conditions tested, the AeroChamber Max offered the best pure performance in terms of drug mass delivery, while the LiteAire was substantially better than the rigid polymer VHCs in terms of device cost per drug mass delivered. This may be of importance to those who wish to optimize the ratio between cost and performance.

VHC Comparison Summary
Holding Chamber Comparisons AeroChamber Max LiteAire OptiChamber Advantage AeroChamber Plus
Cost (US$) $10.95* $2.95 $10.30* $10.30*
Mean Albuterol Sulfate Mass Delivered Per Actuation± SD (μg) 67 ± 4 55 ± 3 52 ± 6 48 ± 8
VHC Cost/Drug Mass Delivered (US$/μg Albuterol Sulfate) $0.16 $0.05 $0.20 $0.21

*Tri-Anim single unit price

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