Using a new type of oxygenator during heart bypass surgery to reduce air bubbles in the blood

Some people experience mild problems affecting their brain after heart surgery. These can include short-term difficulties with thinking, attention, and memory.

1 in 5 people over age 65 who have heart surgery, and 1 in 3 people over age 80 who have heart surgery, experience these problems.

Surgeons believe the brain problems sometimes seen in patients after heart surgery are caused by tiny nitrogen-rich air bubbles in the blood, called gaseous micro-emboli. These tiny air bubbles can get into the blood when it’s circulated in the machine that temporarily takes over the job of the heart and lungs during surgery. This machine is called a heart and lung machine.

An oxygenator is the part of the heart and lung machine that adds oxygen to the blood and removes carbon dioxide. A new type of oxygenator which removes nitrogen has been developed. Using this type of oxygenator may reduce the number of air bubbles in the blood, and therefore in the brain, during heart surgery.

Project aims

We are doing this project to see if there are any differences in the number of air bubbles circulating to the brain during heart surgery using the new oxygenator versus the standard oxygenator in the heart and lung machine.

No one has done this type of study before, so we need to gather information on the number of bubbles we might expect to see and whether people will agree to be recruited to the study. This will allow us to design a bigger study to see if the new oxygenator is a better option than a standard oxygenator.

Our study will involve 40 patients who are having heart operations at Bristol Heart Institute. We will use the new oxygenator with 20 of the patients, and the standard oxygenator with the other 20 patients, to find out which one produces less air bubbles in the blood.

What we hope to achieve

What we find out from this study will help us design a bigger study to compare the two types of oxygenator.

We hope that, eventually, our research might mean people have fewer problems with their brain after heart surgery.