Table of Contents
ISRN Pediatrics
Volume 2012, Article ID 721295, 10 pages
Research Article

Assessing Modeled C O 2 Retention and Rebreathing of a Facemask Designed for Efficient Delivery of Aerosols to Infants

1Faculty of Aeronautics and Astronautics, Institute for Thermodynamics, University of Bundeswehr Munich, 85579 Neubiberg, Germany
2Alnylam Pharmaceuticals Inc., Cambridge, MA 02142, USA
3LeBonheur Children’s Hospital, Memphis, TN 38103, USA
4Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN 38103, USA
5PARI Pharma GmbH, 82166 Gräfelfing, Germany
6Quintiles Ltd., 80639 Munich, Germany
7Department of Molecular Sciences, University of Tennessee Health Science Center, 50 N. Dunlap, Memphis, TN 38103, USA

Received 19 March 2012; Accepted 29 April 2012

Academic Editors: G. J. Casimir, S. K. Patole, and D. D. Trevisanuto

Copyright © 2012 Christian Mundt et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. New aerosol drugs for infants may require more efficient delivery systems, including face masks. Maximizing delivery efficiency requires tight-fitting masks with minimal internal mask volumes, which could cause carbon dioxide (CO2) retention. An RNA-interference-based antiviral for treatment of respiratory syncytial virus in populations that may include young children is designed for aerosol administration. CO2 accumulation within inhalation face masks has not been evaluated. Methods. We simulated airflow and CO2 concentrations accumulating over time within a new facemask designed for infants and young children (PARI SMARTMASK® Baby). A one-dimensional model was first examined, followed by 3-dimensional unsteady computational fluid dynamics analyses. Normal infant breathing patterns and respiratory distress were simulated. Results. The maximum average modeled CO2 concentration within the mask reached steady state (3.2% and 3% for normal and distressed breathing patterns resp.) after approximately the 5th respiratory cycle. After steady state, the mean CO2 concentration inspired into the nostril was 2.24% and 2.26% for normal and distressed breathing patterns, respectively. Conclusion. The mask is predicted to cause minimal CO2 retention and rebreathing. Infants with normal and distressed breathing should tolerate the mask intermittently delivering aerosols over brief time frames.