Heterogeneity of blood flow and metabolism during exercise in patients with chronic obstructive pulmonary disease.

Zafeiris Louvaris, Helmut Habazettl, Andreas Asimakos, Harrieth Wagner, Spyros Zakynthinos, Peter Wagner, Ioannis Vogiatzis

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

The study investigated whether the capacity to regulate muscle blood flow (Q) relative to metabolic demand (VO2) is impaired in COPD. Using six NIRS optodes over the upper, middle and lower vastus lateralis in 6 patients, (FEV1:46 ± 12%predicted) we recorded from each: a) Q by indocyanine green dye injection, b) VO2/Q ratios based on fractional tissue O2 saturation and c) VO2 as their product, during constant-load exercise (at 20%, 50% and 80% of peak capacity) in normoxia and hyperoxia (FIO2:1.0). At 50 and 80%, relative dispersion (RD) for Q, but not for VO2, was greater in normoxia (0.67 ± 0.07 and 0.79 ± 0.08, respectively) compared to hyperoxia (0.57 ± 0.12 and 0.72 ± 0.07, respectively). In both conditions, RD for VO2 and Q significantly increased throughout exercise; however, RD of VO2/Q ratio was minimal (normoxia: 0.12–0.08 vs hyperoxia: 0.13–0.09). Muscle Q and VO2 appear closely matched in COPD patients, indicating a minimal impact of heterogeneity on muscle oxygen availability at submaximal levels of exercise.
Original languageEnglish
Pages (from-to)42-50
JournalRespiratory Physiology and Neurobiology
Volume237
Early online date3 Jan 2017
DOIs
Publication statusPublished - 1 Mar 2017

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