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Carbon Dioxide Insufflation on Cerebral Microemboli

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00715845
Recruitment Status : Terminated (ran out of funding)
First Posted : July 15, 2008
Last Update Posted : October 26, 2011
Information provided by (Responsible Party):
University Health Network, Toronto

Tracking Information
First Submitted Date  ICMJE June 17, 2008
First Posted Date  ICMJE July 15, 2008
Last Update Posted Date October 26, 2011
Study Start Date  ICMJE April 2008
Actual Primary Completion Date April 2010   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (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  ICMJE Same as current
Change History Complete list of historical versions of study NCT00715845 on Archive Site
Current Secondary Outcome Measures  ICMJE
 (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  ICMJE Same as current
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
Descriptive Information
Brief Title  ICMJE Carbon Dioxide Insufflation on Cerebral Microemboli
Official Title  ICMJE 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  ICMJE Interventional
Study Phase  ICMJE Phase 2
Phase 3
Study Design  ICMJE Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Condition  ICMJE
  • Cardiovascular Disease
  • Mitral Valve Repair
  • Cerebral Microemboli
  • Cognitive Decline
Intervention  ICMJE 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  ICMJE Experimental: 2
Intervention: Procedure: Carbon dioxide insufflation
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Recruitment Information
Recruitment Status  ICMJE Terminated
Actual Enrollment  ICMJE
 (submitted: October 25, 2011)
Original Estimated Enrollment  ICMJE
 (submitted: July 11, 2008)
Actual Study Completion Date  ICMJE October 2011
Actual Primary Completion Date April 2010   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

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  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE 18 Years and older   (Adult, Older Adult)
Accepts Healthy Volunteers  ICMJE No
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE Canada
Removed Location Countries  
Administrative Information
NCT Number  ICMJE NCT00715845
Other Study ID Numbers  ICMJE CO200
Has Data Monitoring Committee No
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement  ICMJE Not Provided
Responsible Party University Health Network, Toronto
Study Sponsor  ICMJE University Health Network, Toronto
Collaborators  ICMJE Not Provided
Investigators  ICMJE
Principal Investigator: Patricia Murphy, BSc, MD, FRCPC University Health Network, Toronto
PRS Account University Health Network, Toronto
Verification Date October 2011

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP