Reduced tidal volume increases 'air hunger' at fixed PCO2 in ventilated quadriplegics

Harold L. Manning, Steven A. Shea, Richard M. Schwartzstein, Robert W. Lansing, Robert Brown, Robert B. Banzett

Research output: Contribution to journalArticle

134 Scopus citations

Abstract

The act of breathing diminishes the discomfort associated with hypercapnia and breath-holding. To investigate the mechanisms involved in this effect, we studied the effect of tidal volume (VT) on CO2-evoked air hunger in 5 high-level quadriplegic subjects whose ventilatory capacity was negligible, and who lacked sensory information from the chest wall. Subjects were ventilated at constant frequency with a hyperoxic gas mixture, and end-tidal PCO2 was maintained at a constant but elevated level. VT was varied between the subjects' normal VT and a smaller VT. Subjects used a category scale to rate their respiratory discomfort or 'air hunger' at 30-40 sec intervals. In 4 of 5 subjects there was a strong inverse relationship between breath size and air hunger ratings. The quality of the sensation associated with reduced VT was nearly identical to that previously experienced with CO2 alone. We conclude that afferent information from the lungs and upper airways is sufficient to modify the sensation of air hunger.

Original languageEnglish (US)
Pages (from-to)19-30
Number of pages12
JournalRespiration Physiology
Volume90
Issue number1
DOIs
StatePublished - Oct 1992

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Keywords

  • Breathlessness CO
  • CO
  • Control of breathing
  • Dyspnea
  • Mammals
  • humans
  • respiratory sensation
  • tidal volume (quadriplegics)

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine

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