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

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

Study Overview

• Status: Completed
• Conditions: Effect of High Altitude
• Intervention / Treatment: Other: altitude exposure

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 21
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Zurich, Switzerland, 8091
    • University of Zurich

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Born, raised and currently living <800m
• No overnight stay at altitudes >1500 m 4 weeks before the study

Exclusion Criteria:

• Previous altitude intolerance to altitude <3000 m
• Pregnancy
• Health impairment, which requires regular treatment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Altitude exposure; Acute high altitude exposure followed by 8 day acclimatization and reexposure for 8 days after 6 days at low altitude	Other: altitude exposure; altitude exposure

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation.	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	day 1; day 2 first cycle

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation.	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.	day 1; day 7 first cycle
Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation.	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.	day 2; day 7 second cycle
Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation.	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.	day 2 first cycle; day 2 second cycle
Coherence between middle cerebral artery blood flow velocity and systemic blood pressure as measure of cerebral autoregulation.	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.	day 7 first cycle; day 7 second cycle

Collaborators and Investigators

• Sponsor: University of Zurich
• Collaborators: University of Calgary

Study record dates

Study Major Dates

• Study Start (Actual): April 9, 2016
• Primary Completion (Actual): May 4, 2016
• Study Completion (Actual): May 4, 2016

Study Registration Dates

• First Submitted: April 1, 2016
• First Submitted That Met QC Criteria: July 11, 2016
• First Posted (Estimate): July 12, 2016

Study Record Updates

• Last Update Posted (Actual): January 17, 2019
• Last Update Submitted That Met QC Criteria: January 15, 2019
• Last Verified: January 1, 2019

More Information

Terms related to this study

• Keywords: Cerebral autoregulation; High altitude; Transfer function analysis
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Altitude Sickness
• Other Study ID Numbers: REB15-2709_V4

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO