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HypoxiaCHAIRNCT06399575

Characterizing Hypoxic Apnea Intra-individual Repeatability

A study testing Apnea Following Isocapnic Hypoxia in people with Hypoxia and Apnea, run by University of Alberta at 1 site in Canada.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Apneas (breath-holds) are increasingly being tested in human subjects to understand how the human body operates. Apneas decrease heart rate and increase blood pressure. These findings are driving current research into the effects of oxygen concentrations on the heart rate and blood pressure responses to apneas and the… Read more about this study

Who is it for?
Ages 18 to 70 yearsHealthy volunteers can take part
Conditions the study is for
Hypoxia, Apnea
What is being tested?
Apnea Following Isocapnic Hypoxia
Could I receive a placebo?
No, everyone receives an active treatment
How many people
16 participants
Where
1 siteCanada
Study dates
2 May 2024to 28 Jun 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 to 70 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Males and females between the ages of 18-70

Who cannot join

  • Having known cardiovascular or nervous system disease
  • Low or high blood pressure (< 90/60 or >139/85, respectively)
  • Taking any prescribed medications (other than oral contraceptives) that may affect cardiovascular system function
  • Females who may be pregnant (self-reported)
  • Involved in other studies

Trial locations and contacts

1 site in 1 country.

Canada1 site

  • University of Alberta

    Edmonton, Alberta, T6G 2E1

Other trials in Canada

About this study

Official title: Characterizing the Repeatability and Reproducibility of Cardiovascular Responses to Hypoxic Apneas

Apneas (breath-holds) are increasingly being tested in human subjects to understand how the human body operates. Apneas decrease heart rate and increase blood pressure. These findings are driving current research into the effects of oxygen concentrations on the heart rate and blood pressure responses to apneas and the effect of breath-hold training on these responses. The interest in apnea research is three-fold:

  1. Apneas are a nervous system stressor that can help researchers better understand the fundamental operation of the human body;
  2. Elite divers can use findings from research to better their training and performance; and
  3. The scientific understanding of apneas may translate to a better understanding of sleep apnea.
Read more

Despite this interest, little is known about the repeatability (the consistency within a single day) and reproducibility (the consistency between days) in the heart rate and blood pressure responses to apneas. This uncertainty limits the scientific interpretations from previous results. This study aims to determine the repeatability and reproducibility of heart rate and blood pressure responses to apneas. The goals of the study are:

  1. To provide greater certainty to previous results; and
  2. Inform best practices for future studies.

The study requires 20 healthy volunteers (10 females) and will measure heart rate, blood pressure, breathing parameters (expired gas concentrations, breathing volume and rate), and oxygen saturation. During the protocol, participants will complete two maximal voluntary apneas and five test apneas. The test apneas will all be the same length based on the longer of the two maximal voluntary apneas. Before each apnea, participants will also breathe low oxygen concentrations (hypoxia). Hypoxia provides a bigger decrease in heart rate during apneas than room air which makes it easier to see changes in heart rate responses between apneas (i.e., bigger signal-to-noise ratio). Participants will complete two identical test sessions on back-to-back days. The differences in heart rate and blood pressure responses to the five apneas within each session will determine repeatability and the differences between sessions will determine reproducibility. The investigators hypothesize that repeatability will be good and that repeatability within a session will be better than reproducibility between sessions.

Conditions
Hypoxia, Apnea
Being tested
Apnea Following Isocapnic Hypoxia
Keywords
Repeatability, Reproducibility, Heart Rate
Medical subject headings
Hypoxia, Apnea

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Apnea Following Isocapnic HypoxiaOther

    Decreasing end-tidal partial pressure of oxygen to 50 mmHg for five minutes, targeting 80-85% peripheral oxygen saturation. The end-tidal partial pressure of carbon dioxide will remain +1 mmHg above baseline levels. After five minutes of hypoxia, participants will complete an apnea.

Study groups in NCT06399575
Study groupRoleWhat they receive
Apnea Following Isocapnic HypoxiaExperimentalNot described
Receives: Other: Apnea Following Isocapnic Hypoxia

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Heart Rate

    Electrocardiogram (lead II)

    Measured: Continuous collection during both visits (2 hours on back-to-back days). Data will be extracted during free breathing (1 minute average before each apnea) and during apneas (beat-by-beat extraction from the 10 beats preceding resumption of breathing).

Secondary outcomes (5)

  1. Blood Pressure

    Finger Photoplethysmography

    Measured: Continuous collection during both visits (2 hours on back-to-back days). Data will be extracted during free breathing (1 minute average before each apnea) and during apneas (beat-by-beat extraction from the 10 beats preceding resumption of breathing).

  2. Cardiac Arrhythmias

    Assessed using electrocardiogram (lead II) by a trained researcher and reviewed by a cardiologist. Arrhythmias observable in lead II will be reported as a binary (i.e., yes/no) for each individual for each apnea. Example arrhythmias are premature atrial contractions and sinus pauses, though many more exist.

    Measured: Continuous collection during both visits (2 hours on back-to-back days). Data will be extracted during apneas (beat-by-beat observation from the 10 beats preceding the resumption of breathing).

  3. Peripheral Oxygen Saturation

    Pulse Oximetry

    Measured: Continuous collection during both visits (2 hours on back-to-back days). Data will be extracted during free breathing (1 minute average before each apnea) and during apneas (10 beats preceding the resumption of breathing to 1 minute after apnea end).

  4. Rating of Perceived Exertion

    Participants Rate the Effort of their Apnea using the Modified Borg Scale with scores from 1 to 10 with 1 representing no effort and 10 representing a maximal effort.

    Measured: Apnea (immediately following apnea)

  5. Apnea Duration

    Time, in seconds, from the end of the last breath preceding the apnea to the resumption of breathing.

    Measured: Start to end of apnea: apnea start determined using cessation of flow through the pneumotachometer, apnea end determined using respiratory belt strain gauge. Estimated apnea durations are 15-30 seconds.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted6 May 2024
  2. Study start2 May 2024
  3. Primary completion28 Jun 2024
  4. Study completion28 Jun 2024

Resources

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
Basic science
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
16 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06399575
Sponsor's protocol ID
Pro00138947
Acronym
CHAIR
Status last verified
Jul 2024
First submitted
21 Apr 2024
Last updated
3 Jul 2024
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided

Publications

  • Busch SA, Davies H, van Diepen S, Simpson LL, Sobierajski F, Riske L, Stembridge M, Ainslie PN, Willie CK, Hoiland R, Moore JP, Steinback CD. Chemoreflex mediated arrhythmia during apnea at 5,050 m in low- but not high-altitude natives. J Appl Physiol (1985). 2018 Apr 1;124(4):930-937. doi: 10.1152/japplphysiol.00774.2017. Epub 2017 Dec 21.

    PubMed 29357505

  • Busch SA, van Diepen S, Steele AR, Meah VL, Simpson LL, Figueroa-Mujica RJ, Vizcardo-Galindo G, Villafuerte FC, Tymko MM, Ainslie PN, Moore JP, Stembridge M, Steinback CD. Global REACH: Assessment of Brady-Arrhythmias in Andeans and Lowlanders During Apnea at 4330 m. Front Physiol. 2020 Jan 22;10:1603. doi: 10.3389/fphys.2019.01603. eCollection 2019.

    PubMed 32038287

  • Stanforth PR, Gagnon J, Rice T, Bouchard C, Leon AS, Rao DC, Skinner JS, Wilmore JH. Reproducibility of resting blood pressure and heart rate measurements. The HERITAGE Family Study. Ann Epidemiol. 2000 Jul;10(5):271-7. doi: 10.1016/s1047-2797(00)00047-8.

    PubMed 10942874

  • Hopkins WG. Measures of reliability in sports medicine and science. Sports Med. 2000 Jul;30(1):1-15. doi: 10.2165/00007256-200030010-00001.

    PubMed 10907753

  • Weir JP. Quantifying test-retest reliability using the intraclass correlation coefficient and the SEM. J Strength Cond Res. 2005 Feb;19(1):231-40. doi: 10.1519/15184.1.

    PubMed 15705040

Questions about this trial

What is this clinical trial studying?

A study testing Apnea Following Isocapnic Hypoxia in people with Hypoxia and Apnea, run by University of Alberta at 1 site in Canada.

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 1 inclusion and 5 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: finished, as of the sponsor's last update on 3 Jul 2024. 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 Canada. 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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

Heart Rate (time frame: Continuous collection during both visits (2 hours on back-to-back days). Data will be extracted during free breathing (1 minute average before each apnea) and during apneas (beat-by-beat extraction from the 10 beats preceding resumption of breathing).). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06399575, which also lists 5 linked publications.

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 3 Jul 2024.

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