Monitoring of the Cerebral Tissue Oxygenation and Perfusion in the Adapting Climber During Sleep in High Altitude

Study Overview
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Brief Summary
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One of the major challenges in adapting to high altitudes is that with increasing altitude sleeping quality declines rapidly. Thus, the night sleep can only provide limited to none regeneration. It usually takes a prolonged stay at a constant altitude to adapt sufficiently to the altitude and to have a refreshing night sleep. 1975 Reit et. al showed in their EEG-recordings that the sleep architecture (the regular succession of the particular sleep phases) is disturbed by repeating arousals which occur due to an irregularity in the breathing rhythm. The purpose of this study is to create a better understanding of the underlying mechanisms that lead to failed acclimatization and AMS, due to sleep disturbance.

Detailed Description
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Under sea level conditions humans breath between 10 and 12 times per minute. The breathing cycle in high altitude is accelerated. If the conscious breathing control vanishes during sleep a periodic breathing with alternating episodes of hyperventilation and apnea is the result. This circumstance causes repetitive arousals that do not allow a normal sleep pattern. The associated adverse effects are fatigue, slow or failed acclimatization, weakening of the immune system, lack of motivation and the disability to make rational decisions. Sleep deprivation is a common reason for the abortion of a trip, accidents and severe forms of Acute Mountain Sickness (AMS).

Official Title
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Monitoring of the Cerebral Tissue Oxygenation and Perfusion in the Adapting Climber During the Sleep in High Altitude

Conditions
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Environmental Sleep Disorder, Cheyne-Stokes Respiration, Altitude Sickness

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age: 18 - 80 years voluntary participation in an expedition to Mount Kilimanjaro Exclusion Criteria: obstructive or restrictive respiratory disorder hemodynamic relevant cardiac defect sleep disorder

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| not acclimatized<br>no stay in an altitude above 2500 m within the last 3 Months | |
| acclimatized<br>stay above 2500 m with the last 14 days | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tissue oxygenation index | Measured with near infra-red spectroscopy | participants will be followed for the duration of the expedition, an expected 7 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tissue hemoglobin index | measured with near infra-red spectroscopy | participants will be followed for the duration of the expedition, an expected 7 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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high, altitude, acute, mountain, sickness, sleep, disorder, periodic, breathing, hyperventilation, apnea