Clinical Trial: Effect of High Altitude Exposure, Acclimatization and Re-exposure on Nocturnal Breathing Pattern in Lowlanders

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Interventional

Official Title: Effect of High Altitude Exposure, Acclimatization and Re-exposure on Nocturnal Breathing Pattern in Lowlanders

Brief Summary: Prospective interventional trial in lowlanders evaluating the effect of acute exposure, acclimatization and re-exposure of high altitude on nocturnal breathing pattern.

Detailed Summary:

Respiratory polygraphies will be performed in Santiago de Chile, 520 m, over the course of 3 days. Participants will then travel by commercial airline (5 h flight) and by bus (3 h ride) to the ALMA base camp located at 2900 m near San Pedro de Atacama, northern Chile. Participants will stay there for the next 7 nights and respiratory polygraphies will be performed on night 1 and 6. They will be spend the days (6-8 h daily) at the telescope station at 5050 m while undergoing physiological testing. Daily transports from 2900 to 5050 m will be by car (1 h ride, one way). After the first 8 day altitude sojourn participants will return to the Santiago area (520 m) for a 6 day recovery period.

A second altitude sojourn with an identical schedule as the one described above and a final low altitude stay of 3 days will follow.


Sponsor: University of Zurich

Current Primary Outcome: Mean nocturnal oxygen saturation measured by pulse oximetry [ Time Frame: first sojourn at 5050 m, night 1, 6; second sojourn at 5050 m, night 1, 6; low altitude sojourn at 520 m, night 1 ]

Change in mean nocturnal oxygen saturation over the course of high altitude exposure during 2 sojourns at 5050 m compared to low altitude


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Apnea-/hypopnea index measured by respiratory polygraphy [ Time Frame: first sojourn at 5050 m, night 1, 6; second sojourn at 5050 m, night 1, 6; low altitude sojourn at 520 m, night 1 ]
    Change in apnea-/hypopnea index over the course of high altitude exposure during 2 sojourns at 5050 m compared to low altitude
  • Oxygen desaturation index measured by respiratory polygraphy [ Time Frame: first sojourn at 5050 m, night 1, 6; second sojourn at 5050 m, night 1, 6; low altitude sojourn at 520 m, night 1 ]
    Change in oxygen desaturation index over the course of high altitude exposure during 2 sojourns at 5050 m compared to low altitude
  • Acute mountain sickness measured by the Environmental Symptom questionnaire cerebral score (AMSc) [ Time Frame: first sojourn at 5050 m, day 2, 7; second sojourn at 5050 m, day 2,7; low altitude sojourn at 520 m, day 2 ]
    Incidence of acute mountain sickness (AMSc score >= 0.7) over the course of high altitude exposure during 2 sojourns at 5050 m compared to low altitude


Original Secondary Outcome: Same as current

Information By: University of Zurich

Dates:
Date Received: March 31, 2016
Date Started: March 2016
Date Completion: December 2018
Last Updated: May 23, 2017
Last Verified: May 2017