In:
Journal of Applied Physiology, American Physiological Society, Vol. 117, No. 5 ( 2014-09-01), p. 473-481
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 (DL CO ) relative to individuals born at term (CONT). Low DL CO may predispose PRET to diffusion limitation during exercise, particularly while breathing hypoxic gas because of a reduced O 2 driving gradient and pulmonary capillary transit time. We hypothesized that PRET would have significantly worse pulmonary gas exchange efficiency [i.e., increased alveolar-to-arterial Po 2 difference (AaDO 2 )] during exercise breathing room air or hypoxic gas (FiO 2 = 0.12) compared with CONT. To test this hypothesis, we compared the AaDO 2 in PRET ( n = 13) with a clinically mild reduction in DL CO (72 ± 7% of predicted) and CONT ( n = 14) with normal DL CO (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 O 2 saturation (SaO 2 ), were made prior to and during exercise at 25, 50, and 75% of peak oxygen consumption (V̇o 2peak ) while breathing room air and hypoxic gas. In addition to DL CO , pulmonary function and exercise capacity were significantly less in PRET. Despite PRET having low DL CO , no differences were observed in the AaDO 2 or SaO 2 pre- 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 DL CO resulting from very preterm birth does not cause a measureable reduction in pulmonary gas exchange efficiency.
Type of Medium:
Online Resource
ISSN:
8750-7587
,
1522-1601
DOI:
10.1152/japplphysiol.00307.2014
Language:
English
Publisher:
American Physiological Society
Publication Date:
2014
detail.hit.zdb_id:
1404365-8
SSG:
12
SSG:
31
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