Cardiovascular DiseasePhase 2/3NCT00715845
Carbon Dioxide Insufflation on Cerebral Microemboli
A Phase 2/3 study testing Carbon dioxide insufflation in people with Cardiovascular Disease and Mitral Valve Repair, run by University Health Network, Toronto at 1 site in Canada.
Trial summary
The purpose of this study is to determine if blowing carbon dioxide into the surgical field during open-heart surgery to displace retained chest cavity air from the atmosphere will decrease the number of microembolic being introduced into the heart chambers and brain. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Cardiovascular Disease, Mitral Valve Repair, Cerebral Microemboli
- What is being tested?
- Carbon dioxide insufflation
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteCanada
- Study dates
- Apr 2008to Oct 2011
- Phase
- Phase 2/3
- 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
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- provide informed consent
- male or female who are 18 years of age or older
- elective patients to undergo mitral valve repair +/- coronary artery bypass surgery
- ability to read and write
Who cannot join
- patients with a history of stroke, TIA, carotid vascular disease
- patients with a contraindication to TEE or MRI
- patients with an active history of drug/alcohol dependence or abuse history
Trial locations and contacts
1 site in 1 country.
Canada1 site
Toronto General Hospital/ University Health Network
Toronto, Ontario, M5G 2C4
About this study
Official title: Effects of Carbon Dioxide Insufflation on Cerebral Microemboli During Cardiopulmonary Bypass: A Randomised Trial Correlating Embolic Load & Neurologic Outcomes.
The purpose of this study is to determine if blowing carbon dioxide into the surgical field during open-heart surgery to displace retained chest cavity air from the atmosphere will decrease the number of microembolic being introduced into the heart chambers and brain.
Read the detailed description
Although open-heart surgery is widely used throughout the world, from 1 to 4% of patients experience neurological impairment such as impairment of memory, language and motor skills after surgery. The cause for such cognitive impairment is thought to be air microemboli (very small bubbles of air) being introduced into the blood circulation of the brain from the heart. These air microemboli are introduced from the surgical field and/or from the heart-lung machine. During open-heart surgery, a patient's blood circulation is supported by a heart-lung machine (cardiopulmonary bypass) while the surgeon is replacing or repairing a valve or performing coronary artery bypass surgery. During valve surgery, chambers of the heart are open to room air, causing an introduction of air into the heart. Despite careful de-airing (removal of air) procedures during open-heart surgery, studies revealed that air microemboli are still formed. Past research studies have shown that carbon dioxide (CO2) filling the chest cavity by means of gravity and replacing the room air may help to decrease the amount of microemboli reaching the brain.
CO2 is 50% heavier than room air. Unlike room air, CO2 dissolves more quickly in blood and tissue (> 25 times more soluble in blood and tissue than air) whereas air contains nitrogen, which does not dissolve easily in the blood. In either case, the emboli made of air or CO2 can block the arteries of the brain causing cognitive impairment. Due to the properties of air and CO2, CO2 emboli may be tolerated much better than air emboli.
This is a single-centre, double-blind, placebo-controlled study, randomizing 100 patients undergoing elective mitral valve repair +/- coronary artery bypass grafting. Patients will be divided into 2 groups: (n=100), 50 patients will be receiving carbon dioxide insufflated and 50 patients will not. The number of microemboli will be ascertained by an intraoperative transesophageal echocardiography and transcranial doppler. Three to seven days after surgery, a magnetic resonance imaging of the brain will be done to assess for any cerebral ischemic lesions. Plus, a battery of neuropsychologic tests will be done preoperatively and 2 months postoperatively.
- Being tested
- Carbon dioxide insufflation
- Keywords
- cardiovascular disease, embolism, microemboli, cognitive decline, mitral valve repair, cerebral microemboli, coronary artery bypass graft, CABG, transcranial doppler, transesophageal echocardiogram, magnetic resonance imaging, carbon dioxide
- Medical subject headings
- Cardiovascular Diseases, Cognitive Dysfunction, Embolism
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Carbon dioxide insufflationProcedure or surgery
Also called transeophageal echocardiogram (agilent sonos 5500), cardiopulmonary bypass circuit (sorin S3 roller pump), cardiotomy suction reservoir (dideco), membrane oxygenator (gish vision)
For baseline evaluations, all patients will undergo a battery of neuropsychological testing after obtaining written informed consent and before cardiac surgery. A transesophageal echocardiography and a transcranial doppler will be performed for intraoperative evaluations. For post-operative evaluations, patients will undergo a diffusion-weighted magnetic resonance imaging three to seven days after surgery and have a repeat neuropsychological assessment at six to eight weeks post cardiac surgery. All patients will undergo cardiopulmonary bypass using the same equipment and technique. Patients in both groups will receive a jackson-pratt drain as a gas diffuser. The jackson-pratt drain will be placed 5 cm below the cardiothoracic wound opening adjacent to the diaphragm and if the patient is randomized to carbon dioxide, the flow will be set at 2 litre/min.
| Study group | Role | What they receive |
|---|---|---|
| 2 | Experimental | Not described Receives: Procedure: Carbon dioxide insufflation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Primary outcome will be the number of emboli as measured by transesophageal echocardiogram and transcranial doppler.
Measured: intraoperative
Secondary outcomes (1)
Secondary outcome will be the prevalence of new ischemic lesions on diffusion weighted magnetic resonance imaging and neuropsychological impairments
Measured: 2 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jul 2008 (estimated)
- Study startApr 2008
- Primary completionApr 2010
- Study completionOct 2011
Why it stopped: ran out of funding
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cardiovascular DiseaseStudies of the same condition, open and under way.
- More trials run by University Health Network, TorontoThe 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 2/3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Health Network, Toronto
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Patricia Murphy, BSc, MD, FRCPC, Principal investigator, University Health Network, Toronto
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00715845
- Sponsor's protocol ID
- CO200
- Status last verified
- Oct 2011
- First submitted
- 17 Jun 2008
- Last updated
- 26 Oct 2011
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Oct 2011. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Carbon Dioxide Insufflation on Cerebral Microemboli During Cardiopulmonary Bypass: A Randomised Trial Correlating Embolic Load & Neurologic Outcomes.
- ClinicalTrials.gov ID
- NCT00715845
- Acronym / sponsor ID
- CO200
- Keywords
- cardiovascular disease, embolism, microemboli, cognitive decline, mitral valve repair, cerebral microemboli, coronary artery bypass graft, CABG
- Phase
- Phase 2/3
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: ran out of funding
- Enrolment
- 20 participants (actual)
- Lead sponsor
- University Health Network, TorontoUniversity, hospital or other
- Study start
- Apr 2008
- Primary completion
- Apr 2010 (actual)
- Study completion
- Oct 2011 (actual)
- First posted
- 15 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.
The purpose of this study is to determine if blowing carbon dioxide into the surgical field during open-heart surgery to displace retained chest cavity air from the atmosphere will decrease the number of microembolic being introduced into the heart chambers and brain.
Detailed description
Although open-heart surgery is widely used throughout the world, from 1 to 4% of patients experience neurological impairment such as impairment of memory, language and motor skills after surgery. The cause for such cognitive impairment is thought to be air microemboli (very small bubbles of air) being introduced into the blood circulation of the brain from the heart. These air microemboli are introduced from the surgical field and/or from the heart-lung machine. During open-heart surgery, a patient's blood circulation is supported by a heart-lung machine (cardiopulmonary bypass) while the surgeon is replacing or repairing a valve or performing coronary artery bypass surgery. During valve surgery, chambers of the heart are open to room air, causing an introduction of air into the heart. Despite careful de-airing (removal of air) procedures during open-heart surgery, studies revealed that air microemboli are still formed. Past research studies have shown that carbon dioxide (CO2) filling the chest cavity by means of gravity and replacing the room air may help to decrease the amount of microemboli reaching the brain.
CO2 is 50% heavier than room air. Unlike room air, CO2 dissolves more quickly in blood and tissue (> 25 times more soluble in blood and tissue than air) whereas air contains nitrogen, which does not dissolve easily in the blood. In either case, the emboli made of air or CO2 can block the arteries of the brain causing cognitive impairment. Due to the properties of air and CO2, CO2 emboli may be tolerated much better than air emboli.
This is a single-centre, double-blind, placebo-controlled study, randomizing 100 patients undergoing elective mitral valve repair +/- coronary artery bypass grafting. Patients will be divided into 2 groups: (n=100), 50 patients will be receiving carbon dioxide insufflated and 50 patients will not. The number of microemboli will be ascertained by an intraoperative transesophageal echocardiography and transcranial doppler. Three to seven days after surgery, a magnetic resonance imaging of the brain will be done to assess for any cerebral ischemic lesions. Plus, a battery of neuropsychologic tests will be done preoperatively and 2 months postoperatively.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 2 | Experimental | Procedure: Carbon dioxide insufflation |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- provide informed consent
- male or female who are 18 years of age or older
- elective patients to undergo mitral valve repair +/- coronary artery bypass surgery
- ability to read and write
Key exclusion criteria (3 listed)
- patients with a history of stroke, TIA, carotid vascular disease
- patients with a contraindication to TEE or MRI
- patients with an active history of drug/alcohol dependence or abuse history
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 |
|---|---|---|
| Carbon dioxide insufflationAlso: transeophageal echocardiogram (agilent sonos 5500), cardiopulmonary bypass circuit (sorin S3 roller pump), cardiotomy suction reservoir (dideco), membrane oxygenator (gish vision)For baseline evaluations, all patients will undergo a battery of neuropsychological testing after obtaining written informed consent and before cardiac surgery. A transesophageal echocardiography and a transcranial doppler will be performed for intraoperative evaluations. For post-operative evaluations, patients will undergo a diffusion-weighted magnetic resonance imaging three to seven days after surgery and have a repeat neuropsychological assessment at six to eight weeks post cardiac surgery. All patients will undergo cardiopulmonary bypass using the same equipment and technique. Patients in both groups will receive a jackson-pratt drain as a gas diffuser. The jackson-pratt drain will be placed 5 cm below the cardiothoracic wound opening adjacent to the diaphragm and if the patient is randomized to carbon dioxide, the flow will be set at 2 litre/min. | Procedure or surgery | 2 |
Primary outcome
Primary outcome will be the number of emboli as measured by transesophageal echocardiogram and transcranial doppler.
Time frame: intraoperative
1 secondary outcome
Secondary outcome will be the prevalence of new ischemic lesions on diffusion weighted magnetic resonance imaging and neuropsychological impairments
Time frame: 2 months
Results and safety
The study was stopped early (reason given: ran out of funding). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Oct 2011.
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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.
Patricia Murphy, BSc, MD, FRCPC principal investigator
University Health Network, Toronto
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2/3 study testing Carbon dioxide insufflation in people with Cardiovascular Disease and Mitral Valve Repair, run by University Health Network, Toronto 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 4 inclusion and 3 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: stopped early, as of the sponsor's last update on 26 Oct 2011. 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.
What does this combined phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study was stopped early (reason given: ran out of funding). 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?
Primary outcome will be the number of emboli as measured by transesophageal echocardiogram and transcranial doppler. (time frame: intraoperative). 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 26 Oct 2011.