Effects of intrathoracic pressure, inhalation time, and breath hold time on lung diffusing capacity

Caitlin C. Jorgenson, Kirsten E. Coffman, Bruce D. Johnson

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The single breath hold maneuver for measuring lung diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO) incorporates multiple sources of variability. This study examined how changes in intrathoracic pressure, inhalation time, and breath hold time affect DLCO, DLNO, alveolar-capillary membrane conductance (DmCO) and pulmonary capillary blood volume (Vc) at rest and during submaximal exercise. Thirteen healthy subjects (mean ± SD; age = 26 ± 3y) performed duplicate tests at rest and during submaximal exercise. DLCO and Vc were lower with a positive versus negative intrathoracic pressure during the breath hold at rest (DLCO: 22.2 ± 5.5 vs. 22.7 ± 5.5 ml/min/mmHg, p = 0.028; Vc: 46.5 ± 11.6 vs. 48.2 ± 11.7 ml, p = 0.018). However, during exercise, DLCO and Vc were higher with positive versus negative pressure (DLCO: 26.7 ± 5.5 vs. 25.7 ± 5.7 ml/min/mmHg, p = 0.014; Vc: 56.2 ± 12.6 vs. 53.9 ± 13.1 ml, p = 0.039). The inhalation time did not significantly affect DLCO, DLNO, DmCO or Vc. Short breath hold times (<4s) may yield high DLNO/DLCO ratios and non-physiologic DmCO values. The single breath hold maneuver is useful for evaluating gas transfer at rest and during exercise, however intrathoracic pressure, inhalation time, and breath hold time should be kept consistent between repeated tests.

Original languageEnglish (US)
Pages (from-to)69-75
Number of pages7
JournalRespiratory Physiology and Neurobiology
Volume258
DOIs
StatePublished - Dec 2018

Keywords

  • Alveolar-capillary membrane conductance
  • Pulmonary capillary blood volume
  • Single breath hold maneuver
  • Submaximal exercise

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology
  • Pulmonary and Respiratory Medicine

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