Hypoxia-altitude Testing to Predict Altitude Related Adverse Health Effects in Chronic Obstructive Pulmonary Disease (COPD) Patients

Does Hypoxia-altitude Testing at Lowland Predict Altitude Related Adverse Health Effects in COPD Patients Traveling to 3100m?

The predictive value of the hypoxia altitude simulation test (HAST) or other baseline values to predict altitude-related adverse health effects (ARAHE) is not established. To address this gap, the main goals of this investigation will be 1) to evaluate the diagnostic accuracy of the HAST in identifying individuals that will experience ARAHE during altitude travel and 2) to establish prediction models incorporating other commonly assessed clinical characteristics either alone or in combination with the HAST as predictors of ARAHE in altitude travelers.

Hypotheses: In lowlanders with COPD, a PaO2 <6.6 kPa or another cutoff of PaO2 or SpO2 at the end of the HAST, at rest or during exertion and/or clinical variables including symptoms, pulmonary function indices, 6-min walk distance (6MWD), either alone or combined to a multivariable model, will predict ARAHE during a sojourn of 2 days at 3100m with accuracy greater than chance

Study Overview

• Status: Completed
• Conditions: High Altitude; Hypoxia Altitude Simulation Test
• Intervention / Treatment: Other: hypoxia altitude simulation test (HAST) at 760m; Procedure: High Altitude (3100m)

Detailed Description

Altitude or air travel has become increasingly popular for recreational and professional reasons. Chronic obstructive pulmonary disease (COPD) affects up to 12% of adults worldwide and is associated with progressive hypoxemia, especially during exercise, due to respiratory mechanical constraints, airway obstruction and increasing pulmonary hypertension (PH). COPD patients are at increased risk of ARAHE including acute mountain sickness (AMS) and severe hypoxemia. Factors assessed at lowland that would predict ARAHE of COPD patients exposed to a hypobaric hypoxic environment at altitude or during air travel would be highly warranted. During the HAST COPD-patients are exposed to an inspiratory oxygen fraction (FiO2) of 15.1% corresponding to an altitude of ≈ 2500m and this test was designed to predict deoxygenation at altitude. The predictive value of the HAST or other baseline values to predict ARAHE is not established. To address this gap, the main goals of this investigation will be 1) to evaluate the diagnostic accuracy of the HAST in identifying individuals that will experience ARAHE during altitude travel and 2) to establish prediction models incorporating other commonly assessed clinical characteristics either alone or in combination with the HAST as predictors of ARAHE in altitude travelers.

For this diagnostic accuracy study, COPD-patients with an FEV1 40-80% predicted living < 1000 m without severe hypoxemia (SpO2, <92%), hypercapnia (PaCO2 >6 kPa) or comorbidities will be recruited to traveling to and staying for two nights at 3100 m. At 760 m, the HAST will be performed, at 760 m and 3100 m symptoms, vital signs, SpO2, pulmonary function tests, 6MWD, sleep studies will be repetitively assessed. ARAHE will be defined if one of the following present: AMS with a Lake Louise questionnaire score >4 including headache, or AMSc score ≥0.7, resting SpO2 <80% >30 min or <75% for >15 min; or exercise SpO2 <75% for >5 min accompanied by symptoms, any intercurrent illness including infections, hypertension, neurologic impairments, dyspnea or discomfort at rest requiring oxygen treatment, chest pain and/or ECG signs of cardiac ischemia.

• Study Type: Observational
• Enrollment (Actual): 75

Contacts and Locations

Study Locations

• Kyrgyzstan
  • Bishkek, Kyrgyzstan, 720040
    • National Center of Cardiology and Internal Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 33 years to 73 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

COPD-patients living in the Bishkek area (mean altitude 760m) will be recruited among patients of the outpatient clinic of the National Center for Cardiology and Internal Medicine.

Description

Inclusion Criteria:

• Men and women, age 35-75 y, living at low altitude (<800 m).
• COPD diagnosed according to the Global Initiative for Obstructive Lung Disease (GOLD) guidelines, FEV1 40-80% predicted, pulse oximetry ≥92%, PaCO2 <6 kPa, breathing ambient air at 760 m.

Exclusion Criteria:

• COPD exacerbation, very severe COPD with hypoxemia or hypercapnia at 760 m (see above).
• Other lung disease, relevant comorbidities (such as uncontrolled cardiovascular disease, i.e., unstable arterial hypertension, coronary artery disease; previous stroke; obesity (body mass index >35 kg/m2); internal, neurologic, rheumatologic or psychiatric disease; current heavy smoking (>20 cigarettes per day).
• Renal failure and/or allergy to sulfonamides.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
PaO2 <6.6 kPa or SpO2 < 85% during a HAST in identifying participants with ARAHE	Accuracy of a PaO2 <6.6 kPa during a HAST in identifying participants with ARAHE during the ascent to and stay for 2 days at 3'100 m	3 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
pulse oximetry (SpO2)	At 760 m and 3100m	3 days
six minute walking distance	At 760 m and 3100m	3 days
pulmonary function	Spirometry and single breath carbon monoxide diffusing capacity will be measured	3 days
Nocturnal respiratory polygraphies	Real-time polygraphic data and videostreams will be transmitted to a control station to allow continuous observation by an investigator. This will allow detection of ARAHE at night (in particular severe hypoxemia)	2 nights
Borg Dyspnea Scale	Borg Scale for dyspnea from 0 to 10 (CR10) while 0 means "no dyspnea" and 10 means "highest dyspnea", to assess dyspnea at 760 m and 3100m	3 days
Lake Louise score (2018 version)	Which includes self-assessment of symptoms (headache, fatigue, gastrointestinal discomfort, dizziness), each rated from 0 (absent) to 3 (severe) at 760 m and 3100m.	3 days
Environmental Symptoms Questionnaire cerebral score	Environmental Symptoms Questionnaire cerebral score (AMSc) comprising 11 questions on symptoms rated from 0 (not at all) to 5 (extreme). The weighted sum of responses ranges from 0 to 5. At 760 m and 3100m.	3 days
Arterial blood gas analysis	To assess arterial partial pressure of oxygen (PaO2) at 760 m and 3100m	3 days
The Karolinska sleepiness scale	Sleepiness will be assessed by the Karolinska sleepiness scale at 3200 m. This is a 9-point scale (1 = extremely alert, 3 = alert, 5 = neither alert nor sleepy, 7 = sleepy - but no difficulty remaining awake, and 9 = extremely sleepy - fighting sleep).	2 nights
Blood pressure	At 760 m and 3100m.	3 days

Collaborators and Investigators

• Sponsor: University of Zurich
• Collaborators: National Center of Cardiology and Internal Medicine, Kyrgyz Republic
• Investigators: Study Chair: Silvia Ulrich, Prof, University Hospital, Zürich, Switzerland

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2021
• Primary Completion (Actual): September 1, 2021
• Study Completion (Actual): May 31, 2022

Study Registration Dates

• First Submitted: May 31, 2021
• First Submitted That Met QC Criteria: May 31, 2021
• First Posted (Actual): June 7, 2021

Study Record Updates

• Last Update Posted (Actual): June 27, 2022
• Last Update Submitted That Met QC Criteria: June 20, 2022
• Last Verified: June 1, 2022

More Information

Terms related to this study

• Keywords: Chronic obstructive pulmonary disease; Hypoxia altitude simulation test (HAST); Mountain Sickness; Altitude-related adverse health effects (ARAHE)
• Additional Relevant MeSH Terms: Signs and Symptoms, Respiratory; Hypoxia
• Other Study ID Numbers: 01-2021-SU-HAST

Plan for Individual participant data (IPD)

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

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No