Skip to main content
placeholder image

A comparison of two methods for measuring airway distensibility: Nitrogen washout and forced oscillation technique

Conference Paper


Abstract


  • The measurement of airway stiffness is an important tool for studying airway remodelling in asthma. The relationship between airway calibre and lung volume (airway distensibility) was measured by forced oscillation technique (FOT) and compared with that measured by single-breath nitrogen washout (SBNW). In four non-asthmatic healthy subjects and three asthmatics, anatomical dead space (VDF) was measured by SBNW and respiratory system conductance (Grs) was measured by FOT at 6 Hz. During SBNW testing, 0.51 oxygen boluses were inhaled from three different lung volumes: functional residual capacity (FRC), 1 1 above FRC and near total lung capacity (TLC). Following inhalation of the oxygen bolus subjects exhaled to residual volume and then inhaled to TLC. During FOT, subjects breathed 0.5-1.01 tidal volumes but with gradually increasing end-expiratory lung volume until close to TLC, then returned to normal breathing before inhaling to TLC. This was also repeated but with reducing lung volume from TLC. Absolute lung volumes were measured by body plethysmography and related to volumes during FOT and SBNW by reference to TLC obtained at the end of each SBNW or FOT test manoeuvre. Distensibility was calculated as the linear regression slopes of VDF or Grs versus lung volume. Distensibility measured by VDF ranged 16-37 ml 1-1 lung volume and by Grs it ranged 0.06-0.19 1 s-1 cmH2O-1 1 -1 lung volume. Both distensibility measurements were correlated (Pearson's R2 = 0.91, p = 0.001). The SBNW and FOT are comparable methods for measuring airway distensibility and may have similar clinical usefulness. However, further studies are required to make any specific inferences about the relationship between airway distensibility by FOT and airway remodelling.

Publication Date


  • 2004

Citation


  • Brownn, N. J., Thorpe, C. W., Thompson, B., Berend, N., Downie, S., Verbanck, S., . . . King, G. G. (2004). A comparison of two methods for measuring airway distensibility: Nitrogen washout and forced oscillation technique. In Physiological Measurement Vol. 25 (pp. 1067-1075). doi:10.1088/0967-3334/25/4/022

Scopus Eid


  • 2-s2.0-4344589510

Start Page


  • 1067

End Page


  • 1075

Volume


  • 25

Issue


  • 4

Abstract


  • The measurement of airway stiffness is an important tool for studying airway remodelling in asthma. The relationship between airway calibre and lung volume (airway distensibility) was measured by forced oscillation technique (FOT) and compared with that measured by single-breath nitrogen washout (SBNW). In four non-asthmatic healthy subjects and three asthmatics, anatomical dead space (VDF) was measured by SBNW and respiratory system conductance (Grs) was measured by FOT at 6 Hz. During SBNW testing, 0.51 oxygen boluses were inhaled from three different lung volumes: functional residual capacity (FRC), 1 1 above FRC and near total lung capacity (TLC). Following inhalation of the oxygen bolus subjects exhaled to residual volume and then inhaled to TLC. During FOT, subjects breathed 0.5-1.01 tidal volumes but with gradually increasing end-expiratory lung volume until close to TLC, then returned to normal breathing before inhaling to TLC. This was also repeated but with reducing lung volume from TLC. Absolute lung volumes were measured by body plethysmography and related to volumes during FOT and SBNW by reference to TLC obtained at the end of each SBNW or FOT test manoeuvre. Distensibility was calculated as the linear regression slopes of VDF or Grs versus lung volume. Distensibility measured by VDF ranged 16-37 ml 1-1 lung volume and by Grs it ranged 0.06-0.19 1 s-1 cmH2O-1 1 -1 lung volume. Both distensibility measurements were correlated (Pearson's R2 = 0.91, p = 0.001). The SBNW and FOT are comparable methods for measuring airway distensibility and may have similar clinical usefulness. However, further studies are required to make any specific inferences about the relationship between airway distensibility by FOT and airway remodelling.

Publication Date


  • 2004

Citation


  • Brownn, N. J., Thorpe, C. W., Thompson, B., Berend, N., Downie, S., Verbanck, S., . . . King, G. G. (2004). A comparison of two methods for measuring airway distensibility: Nitrogen washout and forced oscillation technique. In Physiological Measurement Vol. 25 (pp. 1067-1075). doi:10.1088/0967-3334/25/4/022

Scopus Eid


  • 2-s2.0-4344589510

Start Page


  • 1067

End Page


  • 1075

Volume


  • 25

Issue


  • 4