The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts


Michael McPeck; Respiratory Care Services, Long Beach Memorial Medical Center, Long Beach, CA

BACKGROUND: Two different aerosol drug delivery systems claim to enhance Inhaled Aerosol (IA) and shorten treatment time (TT). The Westmed Circulaire II (CIRC) uses the ‘conserver’ principle, incorporating a unidirectional valve and reservoir bag that stores aerosol generated during the patient’s exhalation phase, which would otherwise be wasted, and delivers it on the subsequent inhalation. Conversely, the Monaghan Medical AeroEclipse II Breath-Actuated Nebulizer (BAN) powers the nebulizer jet during inspiration only, to reduce waste during exhalation. Our department was already using the BAN and wished to decrease TT to comply with stricter corporate productivity standards. Acquisition cost differential favored a switch to CIRC but we needed to determine if TT could be shortened with equivalent IA. STUDY QUESTION: How does the IA of the CIRC compare to the BAN during adult and pediatric breathing patterns and different TTs? METHODS: We bench tested 2 new samples each of CIRC and BAN taken from hospital stock. Each device was charged with 2-8 mCi of radiolabeled (99mTc) unit-dose albuterol (2.5 mg in 3 mL 0.9% NaCl). An adjustable piston ventilator created 4 different sinusoidal breathing patterns with a constant 7.5 L/min Minute Volume (f/VT/I-time%): 15/500/50%, 15/500/30%, 30/250/50%, and 30/250/30%. The devices were run on wall air at 50 psig & 8 L/min. IA was captured on HEPA filters positioned at the ‘mouth’ of the lung model. Each test was run up to 12 mins; fresh filters were exchanged every 2 mins; exposed filters were measured in a radioisotope counter and the IA fraction (radioactivity on filter/radioactivity of initial nebulizer charge) was calculated for all filters. IA, expressed as mass of albuterol (mg) delivered to the HEPA filter, was determined by multiplying the IA fraction at 4 and 8 mins by 2.5 (mass of albuterol in mg in Initial Charge). RESULTS: The IA, shown graphically, depicts the mass of IA against TT for 4 breathing patterns. The mean (±SD) IA for the CIRC at 4 mins was 0.66 (±0.09) mg compared to 0.55 (±0.14) mg for the BAN at 8 mins. SUMMARY: CIRC out-performed BAN inasmuch as equivalent IA was delivered in roughly half the time (4 vs 8 mins). CONCLUSION: For equivalent IA delivery, TT with the Circulaire II is significantly shorter than the BAN and, coupled with a favorable supply cost differential, meets our requirements for an aerosol drug delivery system for deliberately shortened routine therapy. Sponsored Research - As mentioned above, I have a consulting relationship with Westmed for public speaking. For this study, I appraoched Westmed to fund a product preference study for our hospital. Westmed rented the aerosol lab and paid for the materials on my behalf but did not direct either me or the study and its methodology or influence the results in any way. They allowed me to be completely independent.