CO2 study
Research type
Research Study
Full title
Carbon Dioxide Insufflation and Brain Protection During Open Heart Surgery: A Randomised Controlled Trial
IRAS ID
278171
Contact name
Diana Benton
Contact email
Sponsor organisation
University Hospitals Bristol and Weston NHS Foundation Trust
Eudract number
2020-001322-54
Duration of Study in the UK
3 years, 4 months, 28 days
Research summary
Brain injury is a complication of open-heart surgery affecting around 6 in 10 people. Most cases are mild such as confusion or memory problems. Occasionally injury can be more severe such as stroke and may increase the risk of developing dementia.
Surgeons believe that brain injury is caused by air bubbles entering the blood stream when the heart is opened during surgery, which travel to the brain blocking blood vessels. It is thought that blowing carbon dioxide, which is heavier and more soluble than air, into the area being operating on (insufflation) will reduce air bubbles entering the blood stream.
The CO2 study aims to evaluate the efficacy and safety of carbon dioxide insufflation (CDI) in patients undergoing planned open-heart valve surgery. CDI will be compared with medical air, which is the same as room air and does not have any affects, this will be a placebo.
704 patients will be recruited from at least eight NHS hospitals and randomised to receive either, CDI or medical air insufflation during surgery. Everything else about the operation will be routine.
Surgeons, Anaesthetists, clinical care teams, Research Nurses and participants will not know which gas has been allocated; only the Perfusionist operating the gas cylinder will know.
A sub-study will be conducted to determine any relationship between brain injury and the amount air bubbles entering the blood stream, the rate of blood flow and the amount of oxygen in the brain during surgery. 100 participants from Bristol will have a transcranial doppler ultrasound of the medial cerebral artery and near-infrared spectrometry during their surgery to evaluate this.
Participants will complete quality of life questionnaires, functional and neurocognitive tests before and three months after surgery. Diffusion weighted magnetic resonance imaging (DWMRI) of the brain will be conducted between 2-10 days post-surgery.REC name
East Midlands - Nottingham 2 Research Ethics Committee
REC reference
20/EM/0130
Date of REC Opinion
15 Jun 2020
REC opinion
Further Information Favourable Opinion