Flicker-induced VasodilatationNCT00719342
Effect of Breathing a Mixture of 92% Oxygen (O2) + 8% Carbon Dioxide (CO2) on Flicker Induced Blood Flow Changes in Ocular Perfusion
A study testing Oxygen + Carbondioxide and full field flickering light at 12.5 Hz in people with Flicker-induced Vasodilatation, run by Medical University of Vienna at 1 site in Austria.
Trial summary
It has been shown that diffuse luminance flicker increases retinal and optic nerve head blood flow. This indicates that a neuro-vascular coupling between neural activity and blood flow exists in the retina as described previously for the brain. Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Flicker-induced Vasodilatation
- What is being tested?
- Oxygen + Carbondioxide and full field flickering light at 12.5 Hz
- How many people
- 24 participants
- Where
- 1 siteAustria
- Study dates
- Jul 2008to Dec 2009
- 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 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Men and Women aged between 18 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings, ametropy < 3 Dpt.
Who cannot join
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- Blood donation during the previous 3 weeks
Trial locations and contacts
1 site in 1 country.
Austria1 site
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, 1090
About this study
Official title: Effect of Breathing a Mixture of 92% O2 + 8% CO2 on Flicker Induced Blood Flow Changes in Ocular Perfusion
It has been shown that diffuse luminance flicker increases retinal and optic nerve head blood flow. This indicates that a neuro-vascular coupling between neural activity and blood flow exists in the retina as described previously for the brain. Although a lot of mediators such as NO, pO2, pCO2, H+ and K+ have been proposed, the mechanism of this coupling is still a matter of controversy. However, it has been shown in an animal experiment, that an increase in blood flow, evoked by diffuse luminance flicker stimulation is paralleled by decrease in pO2 in the tissue. In a recently performed study we could show that breathing of 100% O2 did not influence flicker induced changes in the retina and optic nerve head. However, breathing of 100% oxygen also leads to a pronounced vasoconstriction of the retinal vessels and in turn to a increased tension of the vessel wall. Recent evidence indicates that a combination of 92% O2 and 8% CO2 can, at least partially, counteract the vasoconstrictory effect of O2 and increases tissue pO2. Thus, in this study the investigators set out to investigate the flicker light induced increase in blood flow under a mixture of O2/CO2 .
- Conditions
- Flicker-induced Vasodilatation
- Being tested
- Oxygen + Carbondioxide, full field flickering light at 12.5 Hz
- Keywords
- Retinal vessel diameter, Flicker-induced vasodilatation, Optic nerve head blood flow, Ocular Physiology, Regional Blood Flow
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Oxygen + CarbondioxideDrug
Also called O² + CO², Oxymix
Mixture of 92 % oxygen and 8 % carbon dioxide for inhalation
full field flickering light at 12.5 HzOther
1 minute stimulation with full field flickering light at 12.5 Hz during measurement of vessel diameters and measurement of blood flow.
What is being measured
The primary outcome is the main question the study is designed to answer.
Optic nerve head blood flow
Measured: 1 hour
Retinal vessel diameters
Measured: 1 hour
Secondary outcomes (2)
blood pressure
Measured: 1 hour
pulse rate
Measured: 1 hour
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jul 2008 (estimated)
- Study startJul 2008
- Primary completionMay 2009
- Study completionDec 2009
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Flicker-induced VasodilatationStudies of the same condition, open and under way.
- More trials run by Medical University of ViennaThe sponsor's other registered studies.
- 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 24 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of Vienna
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Gerhard Garhofer, Medical University of Vienna
- Investigators
- Michael Wolzt, MD, Principal investigator, Department of Clinical Pharmacology, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00719342
- Sponsor's protocol ID
- OPHT-030606
- Status last verified
- Nov 2014
- First submitted
- 1 Jul 2008
- Last updated
- 14 Nov 2014
- Results posted
- No
Study at a glance
From the registry record, last updated by the sponsor on 14 Nov 2014. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Breathing a Mixture of 92% O2 + 8% CO2 on Flicker Induced Blood Flow Changes in Ocular Perfusion
- ClinicalTrials.gov ID
- NCT00719342
- Acronym / sponsor ID
- OPHT-030606
- Conditions
- Flicker-induced Vasodilatation
- Keywords
- Retinal vessel diameter, Flicker-induced vasodilatation, Optic nerve head blood flow, Ocular Physiology, Regional Blood Flow
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 24 participants (actual)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- Jul 2008
- Primary completion
- May 2009 (actual)
- Study completion
- Dec 2009 (actual)
- First posted
- 21 Jul 2008 (estimated)
- 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.
It has been shown that diffuse luminance flicker increases retinal and optic nerve head blood flow. This indicates that a neuro-vascular coupling between neural activity and blood flow exists in the retina as described previously for the brain. Although a lot of mediators such as NO, pO2, pCO2, H+ and K+ have been proposed, the mechanism of this coupling is still a matter of controversy. However, it has been shown in an animal experiment, that an increase in blood flow, evoked by diffuse luminance flicker stimulation is paralleled by decrease in pO2 in the tissue. In a recently performed study we could show that breathing of 100% O2 did not influence flicker induced changes in the retina and optic nerve head. However, breathing of 100% oxygen also leads to a pronounced vasoconstriction of the retinal vessels and in turn to a increased tension of the vessel wall. Recent evidence indicates that a combination of 92% O2 and 8% CO2 can, at least partially, counteract the vasoconstrictory effect of O2 and increases tissue pO2. Thus, in this study the investigators set out to investigate the flicker light induced increase in blood flow under a mixture of O2/CO2 .
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Men and Women aged between 18 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings, ametropy < 3 Dpt.
Key exclusion criteria (4 listed)
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- Blood donation during the previous 3 weeks
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 |
|---|---|---|
| Oxygen + CarbondioxideAlso: O² + CO², OxymixMixture of 92 % oxygen and 8 % carbon dioxide for inhalation | Drug | – |
| full field flickering light at 12.5 Hz1 minute stimulation with full field flickering light at 12.5 Hz during measurement of vessel diameters and measurement of blood flow. | Other | – |
Primary outcome
Optic nerve head blood flow
Time frame: 1 hour
Retinal vessel diameters
Time frame: 1 hour
2 secondary outcomes
blood pressure
Time frame: 1 hour
pulse rate
Time frame: 1 hour
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Nov 2014.
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.
Michael Wolzt, MD principal investigator
Department of Clinical Pharmacology, Medical University of Vienna
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Oxygen + Carbondioxide and full field flickering light at 12.5 Hz in people with Flicker-induced Vasodilatation, run by Medical University of Vienna at 1 site in Austria.
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 5 inclusion and 4 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 14 Nov 2014. 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 Austria. 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?
Optic nerve head blood flow (time frame: 1 hour). The study lists 2 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 14 Nov 2014.