Conflict of interest: none.
Original Article: Pulmonary Physiology
Article first published online: 29 MAR 2012
Copyright © 2012 Wiley Periodicals, Inc.
Volume 47, Issue 12, pages 1242–1250, December 2012
How to Cite
Pittman, J. E., Johnson, R. C., Jones, P. W. and Davis, S. D. (2012), Variability of a closed, rebreathing setup for multiple breath wash-out testing in children. Pediatr. Pulmonol., 47: 1242–1250. doi: 10.1002/ppul.22531
Previously presented: Abstract at 2011 American Thoracic Society Conference.
- Issue published online: 15 NOV 2012
- Article first published online: 29 MAR 2012
- Manuscript Accepted: 20 JAN 2012
- Manuscript Received: 5 OCT 2011
- CFF. Grant Numbers: PITTMA10A0, DAVIS08Y2
- NC TraCS. Grant Number: 50KR10936
- respiratory function tests;
- lung function tests;
- cystic fibrosis;
- lung diseases;
The multiple breath wash-out technique (MBW) that measures lung clearance index (LCI) and functional residual capacity (FRC) may be more sensitive than spirometry for identification of early obstructive airways disease. The open MBW setup using mass spectrometry referenced in previous publications is not readily available in the U.S. Our objective was to assess validity and sensitivity of a commercially available device that uses a closed (rebreathing) setup with photoacoustic spectroscopy for MBW testing.
Study Design and Methods
Subjects aged 5–21 who were either healthy or had a history of cystic fibrosis were enrolled. Subjects completed MBW (Innocor device; Innovision, Denmark) and spirometry; measures obtained included LCI, FRC, and forced expiratory volume in 1 sec, as well as changes in end-tidal carbon dioxide levels (CO2) and tidal volume during MBW testing.
Seventeen subjects attempted a total of 76 MBW maneuvers; 80% were completed and 60% met criteria for acceptability; most were unacceptable due to errors in the tracer gas curve. Substantial intra-subject variability for LCI and FRC were noted (mean 26% ± 55 and 36% ± 63, respectively). Subjects were also noted to have significant increases in exhaled CO2 and tidal volume during MBW testing.
In our initial experience using a commercially available closed setup for MBW testing, we found a significant degree of intra-subject variability leading us to suspend testing. Variability could be due to hypercapnea and instability of tidal breathing secondary to the rebreathing setup. Further studies are needed to better understand the closed system MBW setup. Pediatr Pulmonol. 2012; 47:1242–1250. © 2012 Wiley Periodicals, Inc.