Clinical Trial: Effect of High Altitude Exposure, Acclimatization and Re-exposure on Cerebral Autoregulation in Lowlanders

Study Status: Active, not recruiting
Recruit Status: Active, not recruiting
Study Type: Interventional

Official Title: Effect of High Altitude Exposure, Acclimatization and Re-exposure on Cerebral Autoregulation in Lowlanders

Brief Summary: Prospective interventional trial in lowlanders evaluating the effect of acute exposure, acclimatization and re-exposure to high altitude on cerebral autoregulation

Detailed Summary:

Baseline measurements 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 8 nights and they will be spend the days (6-8 h daily) at the telescope station at 5050 m while undergoing testing as described above at the first and the last day at 5050m. 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: Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation. [ Time Frame: day 1; day 2 first cycle ]

Change in magnitude of the coefficient of coherence between blood flow velocity in the middle cerebral artery measured by transcranial ultrasound Doppler and systemic blood pressure at day 2 (5050 m) vs. day 1 (520 m) of the first cycle


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation. [ Time Frame: day 1; day 7 first cycle ]
    Change in magnitude of the coefficient of coherence between blood flow velocity in the middle cerebral artery measured by transcranial ultrasound Doppler and systemic blood pressure at day 7 (5050 m) vs. day 1 (520 m) of the first cycle.
  • Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation. [ Time Frame: day 2; day 7 second cycle ]
    Change in magnitude of the coefficient of coherence between blood flow velocity in the middle cerebral artery measured by transcranial ultrasound Doppler and systemic blood pressure at day 7 (5050 m) vs. day 2 (5050 m) of the second cycle.
  • Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation. [ Time Frame: day 2 first cycle; day 2 second cycle ]
    Change in magnitude of the coefficient of coherence between blood flow velocity in the middle cerebral artery measured by transcranial ultrasound Doppler and systemic blood pressure at day 2 (5050 m) second cycle vs. day 2 (5050 m) of the first cycle.
  • Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation. [ Time Frame: day 7 first cycle; day 7 second cycle ]
    Change in magnitude of the coefficient of coherence between blood flow velocity in the middle cerebral artery measured by transcranial ultrasound Doppler and systemic blood pressure at day 7 (5050 m) second cycle vs. day 7 (5050 m) of the first cycle.


Original Secondary Outcome: Same as current

Information By: University of Zurich

Dates:
Date Received: April 1, 2016
Date Started: March 2016
Date Completion: December 2018
Last Updated: May 23, 2017
Last Verified: May 2017