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Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-36703

Bloch, K E; Latshang, T D; Turk, A J; Hess, T; Hefti, U; Merz, T M; Bosch, M M; Barthelmes, D; Hefti, J P; Maggiorini, M; Schoch, O D (2010). Nocturnal periodic breathing during acclimatization at very high altitude at Mount Muztagh Ata (7,546 m). American Journal of Respiratory and Critical Care Medicine, 182(4):562-568.

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Abstract

RATIONALE: Quantitative data on ventilation during acclimatization at very high altitude are scant. Therefore, we monitored nocturnal ventilation and oxygen saturation in mountaineers ascending Mt. Muztagh Ata (7,546 m).

OBJECTIVES: To investigate whether periodic breathing persists during prolonged stay at very high altitude.

METHODS: A total of 34 mountaineers (median age, 46 yr; 7 women) climbed from 3,750 m within 19-20 days to the summit at 7,546 m. During ascent, repeated nocturnal recordings of calibrated respiratory inductive plethysmography, pulse oximetry, and scores of acute mountain sickness were obtained.

MEASUREMENTS AND MAIN RESULTS: Nocturnal oxygen saturation decreased, whereas minute ventilation and the number of periodic breathing cycles increased with increasing altitude. At the highest camp (6,850 m), median nocturnal oxygen saturation, minute ventilation, and the number of periodic breathing cycles were 64%, 11.3 L/min, and 132.3 cycles/h. Repeated recordings within 5-8 days at 4,497 m and 5,533 m, respectively, revealed increased oxygen saturation, but no decrease in periodic breathing. The number of periodic breathing cycles was positively correlated with days of acclimatization, even when controlled for altitude, oxygen saturation, and other potential confounders, whereas symptoms of acute mountain sickness had no independent effect on periodic breathing.

CONCLUSIONS: Our field study provides novel data on nocturnal oxygen saturation, breathing patterns, and ventilation at very high altitude. It demonstrates that periodic breathing increases during acclimatization over 2 weeks at altitudes greater than 3,730 m, despite improved oxygen saturation consistent with a progressive increase in loop gain of the respiratory control system. Clinical trial registered with www.clinicaltrials.gov (NCT00514826).

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Ophthalmology Clinic
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:2010
Deposited On:16 Dec 2010 13:26
Last Modified:30 Nov 2013 08:28
Publisher:American Thoracic Society
ISSN:1073-449X
Publisher DOI:10.1164/rccm.200911-1694OC
PubMed ID:20442435

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