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      Exercise performance and symptoms in lowlanders with COPD ascending to moderate altitude: randomized trial

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          Abstract

          Objective

          To evaluate the effects of altitude travel on exercise performance and symptoms in lowlanders with COPD.

          Design

          Randomized crossover trial.

          Setting

          University Hospital Zurich (490 m), research facility in mountain villages, Davos Clavadel (1,650 m) and Davos Jakobshorn (2,590 m).

          Participants

          Forty COPD patients, Global Initiative for Obstructive Lung Disease (GOLD) grade 2–3, living below 800 m, median (quartiles) age 67 y (60; 69), forced expiratory volume in 1 second 57% predicted (49; 70).

          Intervention

          Two-day sojourns at 490 m, 1,650 m, and 2,590 m in randomized order.

          Outcome measures

          Six-minute walk distance (6MWD), cardiopulmonary exercise tests, symptoms, and other health effects.

          Results

          At 490 m, days 1 and 2, median (quartiles) 6MWD were 558 m (477; 587) and 577 m (531; 629). At 2,590 m, days 1 and 2, mean changes in 6MWD from corresponding day at 490 m were −41 m (95% CI −51 to −31) and −40 m (−53 to −27), n=40, P<0.05, both changes. At 1,650 m, day 1, 6MWD had changed by −22 m (−32 to −13), maximal oxygen uptake during bicycle exercise by −7% (−13 to 0) vs 490 m, P<0.05, both changes. At 490 m, 1,650 m, and 2,590 m, day 1, resting PaO 2 were 9.0 (8.4; 9.4), 8.1 (7.5; 8.6), and 6.8 (6.3; 7.4) kPa, respectively, P<0.05 higher altitudes vs 490 m. While staying at higher altitudes, nine patients (24%) experienced symptoms or adverse health effects requiring oxygen therapy or relocation to lower altitude.

          Conclusion

          During sojourns at 1,650 m and 2,590 m, lowlanders with moderate to severe COPD experienced a mild reduction in exercise performance and nearly one quarter required oxygen therapy or descent to lower altitude because of adverse health effects. The findings may help to counsel COPD patients planning altitude travel.

          Registration

          ClinicalTrials.gov: NCT01875133

          Related collections

          Most cited references 16

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          A comparison between three rating scales for perceived exertion and two different work tests.

           L Kaijser,  E Borg (2006)
          In the present article, three scales developed by Borg are compared on bicycle ergometer work. In the first study, comparing the Borg Ratings of Perceived Exertion (RPE) and Category scales with Ratio properties (CR10) scales, 40 healthy subjects (12 men and eight women for each scale) with a mean age of about 30 years (SD approximately 6) participated. A work-test protocol with step-wise increase of work loads every minute was used (20 W increase for men and 15 W for women). Ratings and heart rates (HRs) were recorded every minute and blood lactates every third minute. Data obtained with the RPE scale were described with linear regressions, with individual correlations of about 0.98. Data obtained with the CR10 scale could also be described by linear regressions, but when described by power functions gave exponents of about 1.2 (SD approximately 0.4) (with one additional constant included in the power function). This was significantly lower than the exponent of between 1.5 and 1.9 that has previously been observed. Mean individual correlations were 0.98. Blood lactate concentration grew with monotonously increasing functions that could be described by power functions with a mean exponent of about 2.6 (SD approximately 0.6) (with two additional constants included in the power functions). In the second study, where also the more recently developed Borg CR100 scale (centiMax) was included, 24 healthy subjects (12 men and 12 women) with a mean age of about 29 years (SD approximately 3) participated in a work test with a step-wise increase of work loads (25 W) every third minute. Ratings and HRs were recorded. RPE values were described by linear regressions with individual correlations of about 0.97. Data from the two CR scales were described by power functions with mean exponents of about 1.4 (SD approximately 0.5) (with a-values in the power functions). Mean individual correlations were about 0.98. In both studies, a tendency for a deviation from linearity between RPE values and HRs was observed. The obtained deviations from what has previously been obtained for work of longer duration (4-6 min) points to a need for standardization of work-test protocols and to the advantage of using CR scales.
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            Interpretation of treatment changes in 6-minute walk distance in patients with COPD.

            There is uncertainty about the interpretation of changes in the 6-min walk distance (6MWD) in chronic obstructive pulmonary disease (COPD) patients and whether the minimal important difference (MID) for this useful outcome measure exists. Data were used from nine trials enrolling a wide spectrum of COPD patients with 6MWD at baseline and follow-up and used to determine threshold values for important changes in 6MWD using three distribution-based methods. Anchor-based methods to determine a MID were also evaluated. Data were included of 460 COPD patients with a mean+/-sd forced expiratory volume in one second (FEV(1)) of 39.2+/-14.1% predicted and 6MWD of 361+/-112 m at baseline. Threshold values for important effects in 6MWD were between 29 and 42 m, respectively, using the empirical rule effect size and the standardised response mean. The threshold value was 35 m (95% confidence interval 30-42 m) based on the standard error of measurement. Correlations of 6MWD with patient-reported anchors were too low to provide meaningful MID estimates. 6-min walk distance should change by approximately 35 m for patients with moderate to severe chronic obstructive pulmonary disease in order to represent an important effect. This corresponds to a 10% change of baseline 6-min walk distance. The low correlations of 6-min walk distance with patient-reported anchors question whether a minimal important difference exists for the 6-min walk distance.
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              • Article: not found

              Wilderness Medical Society practice guidelines for the prevention and treatment of acute altitude illness: 2014 update.

              To provide guidance to clinicians about best practices, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for prevention and treatment of acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. These guidelines present the main prophylactic and therapeutic modalities for each disorder and provide recommendations about their role in disease management. Recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches to prevention and management of each disorder that incorporate these recommendations. This is an updated version of the original WMS Consensus Guidelines for the Prevention and Treatment of Acute Altitude Illness published in Wilderness & Environmental Medicine 2010;21(2):146-155.
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                Author and article information

                Journal
                Int J Chron Obstruct Pulmon Dis
                Int J Chron Obstruct Pulmon Dis
                International Journal of COPD
                International Journal of Chronic Obstructive Pulmonary Disease
                Dove Medical Press
                1176-9106
                1178-2005
                2018
                26 October 2018
                : 13
                : 3529-3538
                Affiliations
                [1 ]Department of Respiratory Medicine, University Hospital of Zurich, Zurich, Switzerland, konrad.bloch@ 123456usz.ch
                [2 ]Zuercher RehaZentrum Davos, Davos Clavadel, Switzerland
                Author notes
                Correspondence: Konrad E Bloch, Department of Respiratory Medicine, University Hospital of Zurich, Raemistrasse 100, 8091 Zurich, Switzerland, Tel +41 44 255 3828, Fax +41 44 255 4451, Email konrad.bloch@ 123456usz.ch
                [*]

                These authors contributed equally to this work

                Article
                copd-13-3529
                10.2147/COPD.S173039
                6208550
                © 2018 Furian et al. This work is published and licensed by Dove Medical Press Limited

                The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License ( http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed.

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                Original Research

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