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Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-50841

Siebenmann, C; Bloch, K E; Lundby, C; Nussbamer-Ochsner, Y; Schoeb, M; Maggiorini, M (2011). Dexamethasone improves maximal exercise capacity of individuals susceptible to high altitude pulmonary edema at 4559 m. High Altitude Medicine and Biology, 12(2):169-177.

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Abstract

We have previously demonstrated that prophylactic intake of dexamethasone improves maximal oxygen uptake (Vo(2)max) in high altitude pulmonary edema (HAPE) susceptible subjects 4 to 6 h after a 2-day climb to 4559 m. However, since with this ascent protocol HAPE usually develops after the first night at 4559 m or later, we hypothesized that a continued dexamethasone prophylaxis would result in an even more pronounced improvement of Vo(2)max after an additional night at high altitude. Vo(2)max of 24 HAPE susceptibles was evaluated on a bicycle ergometer at an altitude of 490 m and at 24 h after rapid ascent to 4559 m. Subjects were divided into two groups: The control group (n=14) performed both tests without dexamethasone, whereas the dexamethasone group (n=10) received dexamethasone 8 mg twice a day (b.i.d), starting 24 h prior to ascent. At 4559 m, Vo(2)max was 61% ± 6% of the baseline value in the control group and 70% ± 9% in the dexamethasone group (p=0.025). Similarly, O(2) pulse (Vo(2)/heart rate) was 68% ± 7% and 77% ± 11% of baseline, respectively (p=0.043). Arterial O(2) saturation at maximal exercise did not differ between groups, whereas at rest it was 83% ± 10% in the control group and 91% ± 4% in the dexamethasone group (p=0.009). Dexamethasone prophylaxis increased Vo(2)max of HAPE-susceptible individuals after the first night at 4559 m without affecting arterial O(2) saturation at maximal exercise. This might be explained by a sustained effect of dexamethasone on maximal cardiac output and pulmonary O(2) diffusion, both resulting in enhanced convectional O(2) transport to the locomotor muscles.

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Division of Surgical Intensive Care Medicine
04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology

04 Faculty of Medicine > Center for Integrative Human Physiology
04 Faculty of Medicine > University Hospital Zurich > Clinic for Pneumology
DDC:570 Life sciences; biology
610 Medicine & health
Language:English
Date:2011
Deposited On:10 Nov 2011 17:05
Last Modified:04 Dec 2013 23:10
Publisher:Mary Ann Liebert
ISSN:1527-0297
Additional Information:This is a copy of an article published in the High Altitude Medicine and Biology © 2011 copyright Mary Ann Liebert; High Altitude Medicine and Biology is available online at: http://www.liebertonline.com
Publisher DOI:10.1089/ham.2010.1075
PubMed ID:21718165
Citations:Web of Science®. Times Cited: 8
Google Scholar™
Scopus®. Citation Count: 9

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