The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

A NOVEL METHOD TO ASSESS THE SEAL EFFICIENCY OF VALVED HOLDING CHAMBER FACEMASKS

Dirk von Hollen1, Eric Lieberman1, Kurt Nikander1



Background: A facemask is the interface between a valved holding chamber (VHC) and the face of a patient. A small leak between the face and the facemask can reduce the dose delivered.

Methods: A custom designed test rig incorporating a Soft Anatomical Model face replica (SAMfr), based on a 4 year old child, was utilized to test three facemasks: AeroChamber Plus Mask (APM) (Monaghan Medical Corp., Plattsburgh, NY), Pocket Chamber Mask (PCM) (nSpire Health, Inc., Longmont, CO), Prototype Mask (PM) (Respironics, Inc., Respiratory Drug Delivery, Parsippany, NJ). The test rig simulated applied forces to the facemask, while allowing airflow through the facemask and the SAMfr. Airflow through the SAMfr was measured using a mass airflow meter (TSI Inc., Shoreview, MN). A Harvard Respirator (HR) (Harvard Apparatus, Holliston, MA) was used to simulate a pediatric breathing pattern (Vt=155 mL, bpm=25, I:E=1:1.5). The HR was connected directly to the SAMfr to establish a baseline maximum peak inhalation flow (PIF) for each of the facemasks. Weights of 0.45 kg, 0.9 kg and 1.8 kg were applied to the test rig to simulate a clinical application force. The actual PIF through the airflow meter was then recorded over 10 cycles for each of the facemasks with the three applied forces.

Results: The baseline PIF values (L/min) for the different facemasks were: APM=17.23; PCM=17.74; PM=17.58. The PIF values for the facemasks at 0.45 kg, 0.9 kg and 1.8 kg were respectively: APM=9.63, PCM=2.22, PM=17.68; APM=10.57, PCM=4.86, PM=17.75; APM=11.34, PCM=7.13, PM=17.75.

Conclusion: The results indicate that the design and softness of the VHC facemask may be of clinical importance.