Novel method for measuring effects of gas compression on expiratory flow.

Item request has been placed! ×
Item request cannot be made. ×
loading   Processing Request
Read More Add to Saved list
  • Author(s): Sharafkhaneh A;Sharafkhaneh A; Officer TM; Goodnight-White S; Rodarte JR; Boriek AM
  • Source:
    American journal of physiology. Regulatory, integrative and comparative physiology [Am J Physiol Regul Integr Comp Physiol] 2004 Aug; Vol. 287 (2), pp. R479-84. Date of Electronic Publication: 2004 Apr 29.
  • Publication Type:
    Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.
  • Language:
    English
  • Additional Information
    • Source:
      Publisher: American Physiological Society Country of Publication: United States NLM ID: 100901230 Publication Model: Print-Electronic Cited Medium: Print ISSN: 0363-6119 (Print) Linking ISSN: 03636119 NLM ISO Abbreviation: Am J Physiol Regul Integr Comp Physiol Subsets: MEDLINE
    • Publication Information:
      Original Publication: Bethesda, Md. : American Physiological Society
    • Subject Terms:
      Forced Expiratory Volume*; Asthma/*diagnosis ; Pulmonary Disease, Chronic Obstructive/*diagnosis ; Respiratory Function Tests/*methods; Adult ; Aged ; Asthma/physiopathology ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; Models, Biological ; Pulmonary Disease, Chronic Obstructive/physiopathology ; Reproducibility of Results ; Respiratory Function Tests/standards
    • Abstract:
      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 (FEV(1)). 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 FEV(1) corrected for gas compression (NFEV(1)). We measured reproducibility of NFEV(1) in repeated maneuvers within the same session and over a 6-mo interval in patients with chronic obstructive pulmonary disease. Our results demonstrate that NFEV(1) significantly correlated with FEV(1), peak expiratory flow, lung expiratory resistance, and total lung capacity. During intrasession, maneuvers with the highest and lowest FEV(1) showed significant statistical difference in mean FEV(1) (P < 0.005), whereas NFEV(1) from the same maneuvers were not significantly different from each other (P > 0.05). Furthermore, variability of NFEV(1) measurements over 6 mo was <5%. We concluded that our method reliably measures the effect of gas compression on expiratory flow.
    • Grant Information:
      HL-072839 United States HL NHLBI NIH HHS
    • Publication Date:
      Date Created: 20040501 Date Completed: 20040827 Latest Revision: 20200930
    • Publication Date:
      20221213
    • Accession Number:
      10.1152/ajpregu.00573.2003
    • Accession Number:
      15117729