title: Heterogeneity of blood flow and metabolism during exercise in patients with chronic obstructive pulmonary disease.
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 O2saturation and c) VO2as 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 VO2and 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 VO2appear closely matched in COPD patients, indicating a minimal impact of heterogeneity on muscle oxygen availability at submaximal levels of exercise.
authors.affiliation: Faculty of Physical Education and Sport Sciences, National and Kapodistrian University of Athens, Greece; 1st Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, "M. Simou, and G.P. Livanos Laboratories", National and Kapodistrian University of Athens, Greece; Faculty of Kinesiology and Rehabilitation Sciences, Division of Respiratory Rehabilitation, Department of Rehabilitation Sciences KU Leuven, University Hospital Leuven, Leuven, Belgium. Electronic address: zafeiris.louvaris@kuleuven.be.
authors.forename: Zafeiris
authors.initials: Z
authors.lastname: Louvaris
authors.affiliation: Institute of Physiology, Charité Campus Benjamin Franklin, Berlin, Germany; Institute of Anesthesiology, Deutsches Herzzentrum Berlin, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Habazettl
authors.affiliation: 1st Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, "M. Simou, and G.P. Livanos Laboratories", National and Kapodistrian University of Athens, Greece.
authors.forename: Andreas
authors.initials: A
authors.lastname: Asimakos
authors.affiliation: Department of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: Harrieth
authors.initials: H
authors.lastname: Wagner
authors.affiliation: 1st Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, "M. Simou, and G.P. Livanos Laboratories", National and Kapodistrian University of Athens, Greece.
authors.forename: Spyros
authors.initials: S
authors.lastname: Zakynthinos
authors.affiliation: Department of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Wagner
authors.affiliation: Faculty of Physical Education and Sport Sciences, National and Kapodistrian University of Athens, Greece; 1st Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, "M. Simou, and G.P. Livanos Laboratories", National and Kapodistrian University of Athens, Greece; Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University Newcastle, UK.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vogiatzis
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D000886:Anthropometry; D001784:Blood Gas Analysis; D015444:Exercise / Q000502:physiology*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000503:physiopathology*; D012039:Regional Blood Flow / Q000502:physiology*
keywords: Chronic obstructive pulmonary disease; Exercise; Muscle metabolism; Muscle perfusion; NIRS