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This Article Full Text Full Text (PDF) All Versions of this Article: 287/2/R479    most recent 00573.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Sharafkhaneh, A. Articles by Boriek, A. M. Search for Related Content PubMed PubMed Citation Articles by Sharafkhaneh, A. Articles by Boriek, A. M.

INNOVATIVE METHODOLOGY

ENVIRONMENTAL, EXERCISE AND RESPIRATORY PHYSIOLOGY

Novel method for measuring effects of gas compression on expiratory flow

Amir Sharafkhaneh,^1,2 Todd M. Officer,² Sheila Goodnight-White,^1,2 Joseph R. Rodarte,^2, and Aladin M. Boriek²

¹Michael E. DeBakey Veterans Affairs Medical Center and ²Baylor College of Medicine, Houston, Texas 77030

Submitted 1 October 2003 ; accepted in final form 24 April 2004

During forced vital capacity maneuvers in subjects with expiratory flow limitation, lung volume decreases during expiration both by air flowing out of the lung (i.e., exhaled volume) and by compression of gas within the thorax. As a result, a flow-volume loop generated by using exhaled volume is not representative of the actual flow-volume relationship. We present a novel method to take into account the effects of gas compression on flow and volume in the first second of a forced expiratory maneuver (FEV₁). In addition to oral and esophageal pressures, we measured flow and volume simultaneously using a volume-displacement plethysmograph and a pneumotachograph in normal subjects and patients with expiratory flow limitation. Expiratory flow vs. plethysmograph volume signals was used to generate a flow-volume loop. Specialized software was developed to estimate FEV₁ corrected for gas compression (NFEV₁). We measured reproducibility of NFEV₁ in repeated maneuvers within the same session and over a 6-mo interval in patients with chronic obstructive pulmonary disease. Our results demonstrate that NFEV₁ significantly correlated with FEV₁, peak expiratory flow, lung expiratory resistance, and total lung capacity. During intrasession, maneuvers with the highest and lowest FEV₁ showed significant statistical difference in mean FEV₁ (P < 0.005), whereas NFEV₁ from the same maneuvers were not significantly different from each other (P > 0.05). Furthermore, variability of NFEV₁ measurements over 6 mo was <5%. We concluded that our method reliably measures the effect of gas compression on expiratory flow.

flow-volume loop; chronic obstructive pulmonary disease; asthma; lung mechanics

This article has been cited by other articles:

				A. Sharafkhaneh, T. G. Babb, T. M. Officer, N. A. Hanania, H. Sharafkhaneh, and A. M. Boriek The Confounding Effects of Thoracic Gas Compression on Measurement of Acute Bronchodilator Response Am. J. Respir. Crit. Care Med., February 15, 2007; 175(4): 330 - 335. [Abstract] [Full Text] [PDF]

				A Sharafkhaneh, S Goodnight-White, T M Officer, J R Rodarte, and A M Boriek Altered thoracic gas compression contributes to improvement in spirometry with lung volume reduction surgery Thorax, April 1, 2005; 60(4): 288 - 292. [Abstract] [Full Text] [PDF]