Dependence of maximal flow-volume curves on time course of preceding inspiration

J Appl Physiol (1985). 1993 Sep;75(3):1155-9. doi: 10.1152/jappl.1993.75.3.1155.


Thirteen normal subjects, sitting in a body plethysmograph and breathing through a pneumotachograph, performed forced vital capacity maneuvers after a rapid inspiration without or with an end-inspiratory pause (maneuvers 1 and 2) and after a slow inspiration without or with an end-inspiratory pause (maneuvers 3 and 4), the pause lasting 4-6 s. Inspirations were initiated close to functional residual capacity. At all lung volumes, expiratory flow was larger with maneuver 1 than with any other maneuver and, over the upper volume range, larger with maneuver 3 than with maneuver 4, whereas it was similar for maneuvers 2 and 4. Relative to corresponding values with maneuver 4, peak expiratory flow was approximately 16 and approximately 4% larger with maneuvers 1 and 3, respectively, whereas forced expiratory volume in 1 s increased by approximately 5% only with maneuver 1. The time dependence of maximal flow-volume curves is consistent with the presence of viscoelastic elements within the respiratory system (D'Angelo et al. J. Appl. Physiol. 70: 2602-2610, 1991).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Electromyography
  • Female
  • Forced Expiratory Volume
  • Humans
  • Male
  • Maximal Expiratory Flow-Volume Curves*
  • Respiration*
  • Respiratory Muscles / physiology
  • Time Factors
  • Vital Capacity