Altitude HypoxiaPRAGMAXNCT05517044
The Pre-acclimatization Augmented Extreme Altitude Expedition
A study testing Nitrogen tent preacclimatization to high altitude in people with Altitude Hypoxia and Perfusion; Complications, run by University of Zurich at 1 site in Switzerland.
Trial summary
The aim of this study is to investigate the effect of pre-acclimatization in a nitrogen tent at home, ventilated with a slightly increased nitrogen percentage, in preparation for an expedition at extreme altitude. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Altitude Hypoxia, Perfusion; Complications
- What is being tested?
- Nitrogen tent preacclimatization to high altitude
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteSwitzerland
- Study dates
- 4 Aug 2022to Dec 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy
- Active alpinists (active alpinists denotes individuals with regular experience in alpine high mountain climbing in rock, ice and snow terrain of difficulty WS - ZS according to the Swiss Alpine Club (SAC-CAS) grading scale assessed in a self-reporting questionnaire
- age > 18 years
Who cannot join
- history of high-altitude pulmonary edema or cerebral edema
- pregnancy or lactation
- heart failure (AHA Stage B and above)
- pulmonary hypertension
- pulmonary disease excluding mild bronchial asthma
- chronic kidney failure (KDIGO Stage 1 and above)
- chronic liver disease
- subjects with a history of smoking (> 5 PY), and high familiar predisposition for cardiovascular disease, when combined with smoking
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The PRe-Acclimatization auGmented extreMe Altitude eXpedition (PRAGMAX) Randomized Controlled Trial
The aim of this study is to investigate the effect of pre-acclimatization in a nitrogen tent at home, ventilated with a slightly increased nitrogen percentage, in preparation for an expedition at extreme altitude. Specifically, the current study aims to gather knowledge, whether pre-acclimatization, first, leads to improved capillary function during an expedition to extreme altitude, and second, affects incidence of altitude sickness and the likelihood of reaching the expedition destination without oxygen supplementation.
The project will be carried out in two phases corresponding to two randomized controlled trials in healthy volunteers, who are participating in an expedition at extreme altitudes with or without pre-acclimatization.
Read the detailed description
Expeditions to the world's highest peaks are attempted by increasing numbers of alpinists, taking advantage of broad commercial support. At extreme altitude successful functioning, and even survival, are only possible with adequate acclimatization, which consists of time-consuming exposure to gradually higher sleeping altitudes. Generally, an increase in 300-600 m per day at altitudes above 3000 m, and the minimization of cumulative time spend above 6500 m, are considered safe practice. Mainly in an attempt to accelerate expeditions to extreme altitudes, a preacclimatization technique using nitrogen concentration tent induced normobaric hypoxia is increasingly employed in practice, and already part commercial expedition plans. Some previous research indicates that intermittent normobaric hypoxia may reduce the incidence of acute mountain sickness, while the results from other studies remain inconclusive or negative. One study has not found serious adverse effects related to intermittent normobaric hypoxia, such as high-altitude pulmonary or cerebral edema.
Thus, despite the emergence of increasing numbers of commercial expedition programs making use of nitrogen concentration tent preacclimatization protocols, many factors remain unclear. Next to remaining uncertainties regarding the extent of the hypoxic condition induced by these devices, current data does not allow adequate conclusions regarding the choice of optimal preacclimatization protocol, optimal associated ascent profiles, and possible effects on oxygen delivery capacity to the tissue, incidence of high-altitude related disease, and even summit success. Thus, the present study aims to conduct a randomized controlled trial to assess the efficacy of nitrogen concentration tent preacclimatization as part of two expeditions to extreme altitude. The immediate effects of nitrogen concentration tent preacclimatization are assessed through continuous monitoring of oxygen partial pressure in the tent and the hemoglobin oxygen saturation throughout preacclimatization. To test whether preacclimatization is associated with physiologic adaptation, tissue red blood cell perfusion as a main contributor to increase oxygen delivery capacity in the microcirculation throughout acclimatization to extreme altitude, is assessed using non-invasive handheld vital microscopy during preacclimatization and throughout the expedition, and the incidence and severity of high-altitude related disease and summit success, are recorded during the expeditions.
- Conditions
- Altitude Hypoxia, Perfusion; Complications
- Being tested
- Nitrogen tent preacclimatization to high altitude
- Keywords
- Microcirculation, Oxygen delivery capacity, Preacclimatization, nitrogen concentration tent
- Medical subject headings
- Altitude Sickness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nitrogen tent preacclimatization to high altitudeOther
The participants assigned to the preacclimatization group spend a minimum of six hours during sleep, throughout the acclimatization period (four weeks preceding the expedition) in a nitrogen concentration tent (Hypoxico OHG, Traunstein, Germany) set to an environmental PO2 corresponding to an altitude of 2500 masl, with a progression to 5500 masl within 28 days in steps of 1000 m every seven days. Respiratory Polygraphy is used to detect periodic breathing, SpO2, and heart rate continuously during sleep and is performed before and after the designated preacclimatization period, and repetitively when increasing normobaric hypoxia in the group with nitrogen concentration tent preacclimatization.
| Study group | Role | What they receive |
|---|---|---|
| Preacclimatization group | Experimental | The participants assigned to the preacclimatization group will undergo a defined preacclimatization program by sleeping in a nitrogen concentration tent prior to an expedition to high altitude. Receives: Other: Nitrogen tent preacclimatization to high altitude |
| Control group | No intervention | The participants assigned to the control group sleep in their regular environment without use of a nitrogen concentration tent prior to an expedition to a high altitude expedition. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in sublingual total capillary vessel density (TVD) induced by preacclimatization and high-altitude exposure (change from baseline)
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
Measured: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Difference in sublingual functional capillary density (FCD) induced by preacclimatization and high-altitude exposure (change from baseline)
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
Measured: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Difference in sublingual red blood cell velocity (RBCv) induced by preacclimatization and high-altitude exposure (change from baseline)
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
Measured: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Difference in sublingual capillary hematocrits (cHct) induced by preacclimatization and high-altitude exposure (change from baseline)
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
Measured: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Difference in sublingual Tissue red blood cell perfusion (tRBCp) induced by preacclimatization and high-altitude exposure (change from baseline)
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
Measured: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Secondary outcomes (5)
Change in acute mountain sickness (Lake Louise score)
Efficacy of the nitrogen concentration tent for high altitude preacclimatization by means of incidence and severity of acute mountain sickness (LLS-AMS score)
Measured: LLS_AMS score reported: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepal
Summit success
Efficacy of nitrogen concentration tent for high altiude preacclimatization by means of incidence and severity of summit success
Measured: Day 9 of the expedition in Nepal (Summit attempt)
Nitrogen tent
Proportion of preacclimatization time in the nitrogen concentration tent within the target environmental oxygen partial pressure within a 5% boundary
Measured: 4 weeks (prior to the expedition start (preacclimatization))
Low hemoglobin oxygen saturation
Proportion of preacclimatization time with a hemoglobin oxygen saturation below 90%
Measured: 4 weeks (prior to the expedition start (preacclimatization))
Hemoglobin oxgen saturation dips
Occurrence of dips in hemoglobin oxygen saturation below 80% for >5 min during preacclimatization
Measured: 4 weeks (prior to the expedition start (preacclimatization))
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Aug 2022
- Study start4 Aug 2022
- Primary completion22 Nov 2023
- Study completionDec 2024 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Altitude HypoxiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Two independent randomized-controlled trials with each an intervention and a control group.
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Zurich
- Sponsor type
- University, hospital or other
- Collaborators
- Swiss Sportclinic Bern
- Responsible party
- Sponsor
- Investigators
- Matthias P Hilty, PD Dr. med., Principal investigator, University of Zurich
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05517044
- Sponsor's protocol ID
- BASEC 2022-00679
- Acronym
- PRAGMAX
- Status last verified
- Dec 2023
- First submitted
- 3 Aug 2022
- Last updated
- 22 Dec 2023
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 Dec 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The PRe-Acclimatization auGmented extreMe Altitude eXpedition (PRAGMAX) Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT05517044
- Acronym / sponsor ID
- PRAGMAX / BASEC 2022-00679
- Conditions
- Altitude Hypoxia, Perfusion; Complications
- Keywords
- Microcirculation, Oxygen delivery capacity, Preacclimatization, nitrogen concentration tent
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- University of ZurichUniversity, hospital or other
- Collaborators
- Swiss Sportclinic Bern
- Study start
- 4 Aug 2022 (actual)
- Primary completion
- 22 Nov 2023 (actual)
- Study completion
- Dec 2024 (estimated)
- First posted
- 26 Aug 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this study is to investigate the effect of pre-acclimatization in a nitrogen tent at home, ventilated with a slightly increased nitrogen percentage, in preparation for an expedition at extreme altitude. Specifically, the current study aims to gather knowledge, whether pre-acclimatization, first, leads to improved capillary function during an expedition to extreme altitude, and second, affects incidence of altitude sickness and the likelihood of reaching the expedition destination without oxygen supplementation.
The project will be carried out in two phases corresponding to two randomized controlled trials in healthy volunteers, who are participating in an expedition at extreme altitudes with or without pre-acclimatization.
Detailed description
Expeditions to the world's highest peaks are attempted by increasing numbers of alpinists, taking advantage of broad commercial support. At extreme altitude successful functioning, and even survival, are only possible with adequate acclimatization, which consists of time-consuming exposure to gradually higher sleeping altitudes. Generally, an increase in 300-600 m per day at altitudes above 3000 m, and the minimization of cumulative time spend above 6500 m, are considered safe practice. Mainly in an attempt to accelerate expeditions to extreme altitudes, a preacclimatization technique using nitrogen concentration tent induced normobaric hypoxia is increasingly employed in practice, and already part commercial expedition plans. Some previous research indicates that intermittent normobaric hypoxia may reduce the incidence of acute mountain sickness, while the results from other studies remain inconclusive or negative. One study has not found serious adverse effects related to intermittent normobaric hypoxia, such as high-altitude pulmonary or cerebral edema.
Thus, despite the emergence of increasing numbers of commercial expedition programs making use of nitrogen concentration tent preacclimatization protocols, many factors remain unclear. Next to remaining uncertainties regarding the extent of the hypoxic condition induced by these devices, current data does not allow adequate conclusions regarding the choice of optimal preacclimatization protocol, optimal associated ascent profiles, and possible effects on oxygen delivery capacity to the tissue, incidence of high-altitude related disease, and even summit success. Thus, the present study aims to conduct a randomized controlled trial to assess the efficacy of nitrogen concentration tent preacclimatization as part of two expeditions to extreme altitude. The immediate effects of nitrogen concentration tent preacclimatization are assessed through continuous monitoring of oxygen partial pressure in the tent and the hemoglobin oxygen saturation throughout preacclimatization. To test whether preacclimatization is associated with physiologic adaptation, tissue red blood cell perfusion as a main contributor to increase oxygen delivery capacity in the microcirculation throughout acclimatization to extreme altitude, is assessed using non-invasive handheld vital microscopy during preacclimatization and throughout the expedition, and the incidence and severity of high-altitude related disease and summit success, are recorded during the expeditions.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Two independent randomized-controlled trials with each an intervention and a control group.
| Arm | Type | Receives |
|---|---|---|
| Preacclimatization group | Experimental | Other: Nitrogen tent preacclimatization to high altitudeThe participants assigned to the preacclimatization group will undergo a defined preacclimatization program by sleeping in a nitrogen concentration tent prior to an expedition to high altitude. |
| Control group | No intervention | –The participants assigned to the control group sleep in their regular environment without use of a nitrogen concentration tent prior to an expedition to a high altitude expedition. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Healthy
- Active alpinists (active alpinists denotes individuals with regular experience in alpine high mountain climbing in rock, ice and snow terrain of difficulty WS - ZS according to the Swiss Alpine Club (SAC-CAS) grading scale assessed in a self-reporting questionnaire
- age > 18 years
Key exclusion criteria (8 listed)
- history of high-altitude pulmonary edema or cerebral edema
- pregnancy or lactation
- heart failure (AHA Stage B and above)
- pulmonary hypertension
- pulmonary disease excluding mild bronchial asthma
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Nitrogen tent preacclimatization to high altitudeThe participants assigned to the preacclimatization group spend a minimum of six hours during sleep, throughout the acclimatization period (four weeks preceding the expedition) in a nitrogen concentration tent (Hypoxico OHG, Traunstein, Germany) set to an environmental PO2 corresponding to an altitude of 2500 masl, with a progression to 5500 masl within 28 days in steps of 1000 m every seven days. Respiratory Polygraphy is used to detect periodic breathing, SpO2, and heart rate continuously during sleep and is performed before and after the designated preacclimatization period, and repetitively when increasing normobaric hypoxia in the group with nitrogen concentration tent preacclimatization. | Other | Preacclimatization group |
Primary outcome
Difference in sublingual total capillary vessel density (TVD) induced by preacclimatization and high-altitude exposure (change from baseline)
Time frame: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
Difference in sublingual functional capillary density (FCD) induced by preacclimatization and high-altitude exposure (change from baseline)
Time frame: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
Difference in sublingual red blood cell velocity (RBCv) induced by preacclimatization and high-altitude exposure (change from baseline)
Time frame: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
Difference in sublingual capillary hematocrits (cHct) induced by preacclimatization and high-altitude exposure (change from baseline)
Time frame: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
Difference in sublingual Tissue red blood cell perfusion (tRBCp) induced by preacclimatization and high-altitude exposure (change from baseline)
Time frame: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa
Sublingual microcirculatory functional hemodynamic variable measured using a handheld vital microscopy. (ref: Communications Biology 2019; 2: 217 UND ref. Curr Opin Crit Care 2020; 26: 273-280.)
5 secondary outcomes
Change in acute mountain sickness (Lake Louise score)
Time frame: LLS_AMS score reported: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepal
Summit success
Time frame: Day 9 of the expedition in Nepal (Summit attempt)
Nitrogen tent
Time frame: 4 weeks (prior to the expedition start (preacclimatization))
Low hemoglobin oxygen saturation
Time frame: 4 weeks (prior to the expedition start (preacclimatization))
Hemoglobin oxgen saturation dips
Time frame: 4 weeks (prior to the expedition start (preacclimatization))
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Dec 2023.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Matthias P Hilty, PD Dr. med. principal investigator
University of Zurich
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Nitrogen tent preacclimatization to high altitude in people with Altitude Hypoxia and Perfusion; Complications, run by University of Zurich at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 22 Dec 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in sublingual total capillary vessel density (TVD) induced by preacclimatization and high-altitude exposure (change from baseline) (time frame: Microcirculation assessment taken: 4 and 1 week prior to the expedition start (preacclimatization), Day 5 to 10 of the expedition in Nepal, Day 2 after the return from Nepa). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Dec 2023.