Development of a multi-modality blood conservation strategy in cardiothoracic surgery

In the UK, cardiac surgery uses more than 6% of all donor blood. However, there is huge variation nationally in transfusion rates (25-95% in cardiac surgery), due to the poor evidence base for transfusion decisions, implying that many transfusions are avoidable. Unnecessary transfusion has direct resource implications, compounded by increasing pressure on the donor supply, as well as indirect resource implications as a consequence of morbidity associated with transfusion. The aim of this programme is to develop a multi-modal strategy to improve the use of blood in adult cardiac surgery, and more specifically to:

A.    Predict transfusion risk before surgery
B.    Reduce unnecessary use of blood
C.    Make blood transfusion safer.

These aims are addressed by three studies.

Coagulation and platelet laboratory testing in cardiac surgery (COPTIC)
The COPTIC study investigates whether it is useful to perform blood tests either just before or at the end of cardiac surgery to identify blood clotting abnormalities in patients.  This study addresses aims A and B.   The health economics work will determine whether laboratory measurement of the function of blood platelets before surgery is likely to be an efficient approach to identifying which patients will have more bleeding. This will involve inferring (using a simple decision model) what would happen with the new alternative approach compared with current practice.  We will also assess the costs and consequences of supplementing existing post-operative point of care tests of coagulopathy with additional laboratory assays to improve their diagnostics accuracy.

Patient-specific cerebral oxygenation monitoring as part of an algorithm to reduce transfusion during heart valve surgery: a randomised controlled trial (PASPORT)
This health economics component (addressing aim B) will explore whether patient-specific transfusion algorithms reduce unnecessary transfusions and improve patient outcomes compared to generic algorithms. This work should enable us to produce a cost per transfusion avoided.

A randomised controlled trial of red cell washing for the attenuation of transfusion associated organ injury in cardiac surgery (REDWASH)
This study addresses aim C. The trial investigates whether outcomes for patients undergoing cardiac surgery likely to require massive transfusion of red blood cells (RBCs) are improved if the RBCs are washed prior to transfusion compared to standard care (no washing).  Here the health economics will focus on the avoidance of postoperative ischaemic complications and infections. We will estimate the resources and costs associated with making transfusion safer by removing the toxic by-products that accumulate during blood storage. This will create a cost per complication (e.g. stroke) avoided.