Pulmonary gas exchange efficiency during exercise breathing normoxic and hypoxic gas in adults born very preterm with low diffusion capacity

Joseph W. Duke, Jonathan E. Elliott, Steven S. Laurie, Kara M. Beasley, Tyler S. Mangum, Jerold A. Hawn, Igor M. Gladstone, Andrew T. Lovering

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

Adults with a history of very preterm birth (<32 wk gestational age; PRET) have reduced lung function and significantly lower lung diffusion capacity for carbon monoxide (DLCO) relative to individuals born at term (CONT). Low DLCOmay predispose PRET to diffusion limitation during exercise, particularly while breathing hypoxic gas because of a reduced O2driving gradient and pulmonary capillary transit time. We hypothesized that PRET would have significantly worse pulmonary gas exchange efficiency [i.e., increased alveolar-to-arterial PO2difference (AaDO2)] during exercise breathing room air or hypoxic gas (FIO2= 0.12) compared with CONT. To test this hypothesis, we compared the AaDO2in PRET (n = 13) with a clinically mild reduction in DLCO(72 ± 7% of predicted) and CONT (n = 14) with normal DLCO(105 ± 10% of predicted) pre- and during exercise breathing room air and hypoxic gas. Measurements of temperature-corrected arterial blood gases, and direct measure of O2saturation (SaO2), were made prior to and during exercise at 25, 50, and 75% of peak oxygen consumption (V O2peak) while breathing room air and hypoxic gas. In addition to DLCO, pulmonary function and exercise capacity were significantly less in PRET. Despite PRET having low DLCO, no differences were observed in the AaDO2or SaO2pre- or during exercise breathing room air or hypoxic gas compared with CONT. Although our findings were unexpected, we conclude that reduced pulmonary function and low DLCOresulting from very preterm birth does not cause a measureable reduction in pulmonary gas exchange efficiency. Copyright

Original languageEnglish (US)
Pages (from-to)473-481
Number of pages9
JournalJournal of Applied Physiology
Volume117
Issue number5
DOIs
StatePublished - Sep 1 2014
Externally publishedYes

Keywords

  • Diffusion limitation
  • Ex-preterms
  • Exercise
  • Hypoxia
  • Pulmonary gas exchange efficiency

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Fingerprint

Dive into the research topics of 'Pulmonary gas exchange efficiency during exercise breathing normoxic and hypoxic gas in adults born very preterm with low diffusion capacity'. Together they form a unique fingerprint.

Cite this