| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
2 Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, USA; Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA, USA
* To whom correspondence should be addressed. E-mail: scgeorge{at}uci.edu.
Exhaled nitric oxide (NO) arises from both airway and alveolar regions of the lungs which provides an opportunity to characterize region-specific inflammation. Current methodologies rely on vital capacity breathing maneuvers and controlled exhalation flow rates which can be difficult to perform, especially for young children and individuals with compromised lung function. In addition, recent theoretical and experimental studies demonstrate that gas phase axial diffusion of NO has a significant impact on the exhaled NO signal. We have developed a new technique to characterize airway NO which requires a series of progressively increasing breathhold times followed by exhalation of only the airway compartment. Using our new technique, we determined values (mean ± SE) in healthy adults (20-38 years, n=8) for the airway diffusing capacity (4.5 ± 1.6 pl*s-1*ppb-1), the airway wall concentration (1340 ± 213 ppb), and the maximum airway wall flux (4350 ± 811 pl/s). The new technique is simple to perform, and application of this data to simpler models with cylinder airways and no axial diffusion yields parameters consistent with previous methods. Inclusion of axial diffusion as well as an anatomically correct trumpet-shaped airway geometry results in significant loss of NO from the airways to the alveolar region profoundly impacting airway NO characterization. In particular, the airway wall concentration is more than an order of magnitued larger than previous estimates in healthy adults, and may approach concentrations (~ 5 nM) which can influence physiological processes such as smooth muscle tone in disease states such as asthma.
This article has been cited by other articles:
|
|
 |
|
  Y. Kerckx, A. Michils, and A. Van Muylem Airway contribution to alveolar nitric oxide in healthy subjects and stable asthma patients J Appl Physiol, April 1, 2008; 104(4): 918 - 924. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Venegas Linking ventilation heterogeneity and airway hyperresponsiveness in asthma Thorax, August 1, 2007; 62(8): 653 - 654. [Full Text] [PDF]
|
|
|
|
|
|
P. Condorelli, H.-W. Shin, A. S. Aledia, P. E. Silkoff, and S. C. George A simple technique to characterize proximal and peripheral nitric oxide exchange using constant flow exhalations and an axial diffusion model J Appl Physiol, January 1, 2007; 102(1): 417 - 425. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H.-W. Shin, P. Condorelli, and S. C. George Examining axial diffusion of nitric oxide in the lungs using heliox and breath hold J Appl Physiol, February 1, 2006; 100(2): 623 - 630. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
