Investigations into Cold Stored Platelets for Pre-Hospital Emergency Resuscitation

Trauma is the leading cause of death for people aged 44 and under in the UK, with 17,000 deaths reported yearly. It has been proven that the number of deaths and time in hospital for patients with traumatic injuries is less when critical care treatment is given to patients before they are transported to a hospital.

In 2015 the Emergency Medical Retrieval and Transfer Service (EMRTS) was set up to provide this critical care treatment in emergencies. The EMRTS can do more advanced tasks than standard ambulance care can, such as giving blood transfusions.

Platelets, the cells within the blood that form clots and stop bleeding, are used to treat major bleeding within hospitals. However, platelets are challenging to store and transport, as they need to be constantly shaken and kept warm (20-24oC), and they must be used within seven days. The EMRTS cannot store these platelets at these standard conditions.

Recent research has found that it is possible to make Cold Stored Platelets (CSP), which are platelets stored at 4 to 6 degrees Celsius, at about the same temperature as a food fridge. The CSP do not need to be shaken like standard platelets, making them easier to store.

The CSP are thought to be better at forming  clots and stopping bleeding,  even  though they don't last as long in the body as the standard platelets. CSP also have a shelf life of up to two weeks, double the shelf life of the standard platelets. CSP are now licensed in the USA and Norway to treat bleeding patients.

We think we can use CSP in Wales for critical care treatment because they are easier to store and have a longer shelf life, and the EMRTS could carry CSP with them to treat patients who are bleeding before they arrive at the hospital. CSP can be added to the same box that the EMRTS already use for red blood cells. Due to a longer shelf life of CSP, there will be less wastage if CSP are not used within the standard 7 days. Thus, this would provide the EMRTS with the same blood products to hand to treat patients with major bleeding as they would in a hospital.

This study first aims to test how well we can store CSP in the EMRTS box with red cells. A laboratory-based study will test the quality of CSP stored with red cells in the EMRTS box and compare the results to CSP stored in a fridge and the standard platelets that are stored warm (20- 24oC). This will tell us if we can use the EMRTS cold box to carry CSP.

We will then look at the records in the Trauma Audit and Research Network database. We will look for the records when the EMRTS gave a blood transfusion to a patient before they reached the hospital. A doctor will decide if a platelet transfusion might have been more suitable if it was available at the time. This information will estimate the demand for CSP from the Welsh Blood Service if they are available to the EMRTS in future.

The results of this project will be published. We will publish in high-quality medical journals. We also plan to travel to national and international conferences  to share our results with other doctors and air ambulance services worldwide. If the above project shows us there is a demand, one of the following things to do is provide evidence that the CSP work well. We can look at the quality performance of CSP over time, as that is more cost-effective for funders. Once we know there is potential to treat a patient with CSP, we would need to test how well CSP treats bleeding through a clinical trial.