AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Non-Symmetrical pMDI Aerosol Deposition on a Spacer
ELIZABETH SPRIGGE, Sandra Fiset, Edgar Matida, Carleton University
Abstract Number: 544 Working Group: Health Related Aerosols
Abstract Spacer devices are used alongside pressurized metered dose inhalers (pMDIs) to assist in the delivery of beta-2 agonist medication to the lungs. A number of volumes are available, all of which are proven to increase the efficacy of the pMDI, as well as reducing the amount of medication deposited in the oropharyngeal and oropharynx regions. It has been found that medication is lost in the spacer device itself.
In this study, a large volume (750 ml) spacer device has been tested to determine the areas at which the most deposition of medication (Salbutamol) occurs. By considering the spacer in four quarters, UV spectrophotometry has been used to calculate the concentration (and hence amount) of deposition in each area as well as the amount of medication released to the patient and that which is lost in the actuator. Inhalation for five different flow rates (7.5, 15, 30, 45, and 60 L/min) was simulated using a vacuum pump.
Simulations have been performed with ANSYS CFX to further study the deposition occurring within the spacer. Using unsteady Reynolds averaged Navier-Stokes (URANS) equations; flow through a simplified model of the spacer has been recreated to further study effects of deposition.
Results reinforce previous literature suggesting that the spray angle of the actuator is downwards, as a greater amount of deposition occurs on the lower half of the spacer, and also suggest that the amount of medication that will reach the patient increases with increasing inspiratory flow rate. Both experimental and numerical results indicate that inertial impaction, rather than turbulence, will affect the deposition within the spacer.