Carbon Dioxide Insufflation on Cerebral Microemboli

• ClinicalTrials.gov Identifier: NCT00715845
• Recruitment Status: Terminated
• First Posted: July 15, 2008
• Last Update Posted: October 26, 2011
• Sponsor: University Health Network, Toronto
• Information provided by (Responsible Party): University Health Network, Toronto

Tracking Information

• First Submitted Date: June 17, 2008
• First Posted Date: July 15, 2008
• Last Update Posted Date: October 26, 2011
• Study Start Date: April 2008
• Actual Primary Completion Date: April 2010 (Final data collection date for primary outcome measure)
• Current Primary Outcome Measures (submitted: July 11, 2008): Primary outcome will be the number of emboli as measured by transesophageal echocardiogram and transcranial doppler. [ Time Frame: intraoperative ]
• Original Primary Outcome Measures: Same as current
• Change History: Complete list of historical versions of study NCT00715845 on ClinicalTrials.gov Archive Site
• Current Secondary Outcome Measures (submitted: July 11, 2008): Secondary outcome will be the prevalence of new ischemic lesions on diffusion weighted magnetic resonance imaging and neuropsychological impairments [ Time Frame: 2 months ]
• Original Secondary Outcome Measures: Same as current
• Current Other Pre-specified Outcome Measures: Not Provided
• Original Other Pre-specified Outcome Measures: Not Provided

Descriptive Information

• Brief Title: Carbon Dioxide Insufflation on Cerebral Microemboli
• Official Title: Effects of Carbon Dioxide Insufflation on Cerebral Microemboli During Cardiopulmonary Bypass: A Randomised Trial Correlating Embolic Load & Neurologic Outcomes.
• Brief 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.

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 Type: Interventional
• Study Phase: Phase 2; Phase 3
• Study Design: Allocation: Randomized; Intervention Model: Parallel Assignment; Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor); Primary Purpose: Prevention

Condition

• Cardiovascular Disease
• Mitral Valve Repair
• Cerebral Microemboli
• Cognitive Decline

Intervention

Procedure: Carbon dioxide insufflation

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.

Other Names:

• transeophageal echocardiogram (agilent sonos 5500)
• cardiopulmonary bypass circuit (sorin S3 roller pump)
• cardiotomy suction reservoir (dideco)
• membrane oxygenator (gish vision)
• transcranial doppler (spencer technologies PMD 100)
• magnetic resonance imaging (GE)

Study Arms

Experimental: 2

Intervention: Procedure: Carbon dioxide insufflation

• Publications *: Not Provided

Recruitment Information

• Recruitment Status: Terminated
• Actual Enrollment (submitted: October 25, 2011): 20
• Original Estimated Enrollment (submitted: July 11, 2008): 100
• Actual Study Completion Date: October 2011
• Actual Primary Completion Date: April 2010 (Final data collection date for primary outcome measure)

Eligibility Criteria

Inclusion Criteria:

• 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

Exclusion Criteria:

• 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

Sex/Gender

• Sexes Eligible for Study: All

• Ages: 18 Years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Contacts: Contact information is only displayed when the study is recruiting subjects
• Listed Location Countries: Canada

Administrative Information

• NCT Number: NCT00715845
• Other Study ID Numbers: CO200
• Has Data Monitoring Committee: No
• U.S. FDA-regulated Product: Not Provided
• IPD Sharing Statement: Not Provided
• Responsible Party: University Health Network, Toronto
• Study Sponsor: University Health Network, Toronto
• Collaborators: Not Provided

Investigators

• Principal Investigator: Patricia Murphy, BSc, MD, FRCPC; University Health Network, Toronto

• PRS Account: University Health Network, Toronto
• Verification Date: October 2011