Blood 'Cleaning' may bring relief to High-Altitude sufferers
NCT ID NCT04557995
First seen Jun 24, 2026 · Last updated Aug 26, 2026 · Updated 3 times
Summary
This study tests whether a procedure called erythrocytapheresis—which removes extra red blood cells from the blood using a machine—can safely reduce symptoms of chronic mountain sickness. The trial will enroll 112 long-term high-altitude residents with very high hemoglobin levels. Researchers will measure symptom scores and walking ability to see if the procedure helps.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- erythrocytapheresis (a procedure that removes excess red blood cells using a machine)
- What this could lead to
- If it works, this could provide a safe, non-drug way to relieve symptoms like headache and fatigue in people with chronic mountain sickness.
- What could go wrong
- This is a relatively small trial (112 people) and the procedure is not a cure—it only manages symptoms temporarily. Risks include side effects from the blood separation process.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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About 112 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Jul 2025
- Expected to finish
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Oct 2029
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion: 1. Age ≥18 years; 2. High-altitude residents or long-term dwellers (continuous residence at ≥2500 meters above sea level for at least 1 year), with no travel history to low-altitude areas in the past 3 months; 3. Hemoglobin (Hb): Men: ≥210 g/L, Women: ≥190 g/L; at least one symptom or sign: headache, dizziness, dyspnea, palpitations, sleep disturbances, fatigue, localized cyanosis, burning sensation in palms/soles, venous dilatation, muscle/joint pain, loss of appetite, poor concentration, or memory changes; CMS total score ≥6; 4. Written informed consent obtained from patients or their legal representatives. Exclusion: 1. Hematocrit \< 60%; 2. Patients with erythrocytosis attributable to: polycythemia vera; secondary erythrocytosis due to dehydration, cyanotic congenital heart disease, or chronic obstructive pulmonary disease; or other underlying hematologic or oncologic conditions; 3. Patients with active pneumonia, pulmonary embolism, or severe organ dysfunction (including cardiac, hepatic, or renal failure); 4. Patients with contraindications to study procedures (including erythrocytapheresis, pulmonary function tests, or incremental shuttle walk test), such as impaired consciousness, pneumothorax, severe arrhythmia, or significant coagulation disorders; 5. Patients who have received CMS-specific interventions within the last 6 months, including phlebotomy, erythrocytapheresis, or targeted pharmacotherapy; 6. Patients currently pregnant, breastfeeding, or planning to become pregnant within 1 year; 7. Any terminal condition with an estimated life expectancy of \< 6 months; 8. Current participation in other clinical trials.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
1 site. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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NO.953 Hospital
RECRUITINGXigazê, Tibet, 857000, China