PerDeCT device (Pericardial Device for monitoring Cardiac output and the diagnosis of Tamponade)

45,000 patients a year have open heart surgery in the UK. Most surgery is coronary artery bypass, the rest includes valve surgery, transplantation and congenital heart surgery.

At surgery the chest is opened through the midline and the sac containing the heart (pericardium) is opened. When the surgery is finished the bone (sternum), muscle and skin are closed. The pericardium is left open but still forms a closed sac around the heart. Some bleeding postoperatively is inevitable and so at least one tube (drain) is left inside the pericardium to drain any blood. Patients may require blood transfusion and occasionally must return to theatre to stop the bleeding.

In up to 3% of patients, blood collects around the heart inside the pericardium and starts to clot which may block the drains. Small amounts do not matter but if the collection of clot and blood is large enough it will start to compress the heart and stop it working properly. This is called cardiac tamponade, left untreated the heart will eventually stop pumping completely and a cardiac arrest occurs. This is very dangerous as external chest compression (CPR) doesn't work as the heart is already fully compressed.

If the diagnosis is made early, the patient is returned to theatre, the chest re-opened, and the clot removed. However, the diagnosis is often very difficult as the vital signs monitored routinely can change as the result of other causes and the blood cannot be seen collecting in the pericardium. If diagnosis is delayed, then the chest will have to be re-opened in the Intensive Care Unit. This is far from ideal and leads to up to a tenfold increase in mortality and morbidity.

This research project is to develop a simple, patented, balloon device (PerDeCT) which is inserted into the pericardial space at surgery. A small probe is also placed around the pulmonary artery to allow accurate measurements of the flow of blood from the heart. Gently inflating the balloon and measuring the flow allows for the much earlier detection of cardiac tamponade. The balloon and probe can be removed at the same time as the chest drains without the need to re-open the chest.

Our team is led by a senior cardiothoracic surgeon and brings together experts in medical device design, testing and regulatory support. PerDeCT will have a major impact on patient safety and the very significant costs of missed tamponade.