Blood transfusions after cardiac surgery may be unnecessary

Blood transfusions carried out after cardiac surgery could be unnecessary and might cause health complications for patients.

Thanks to a £1 million grant by the National Institute for Health Research Health Technology Assessment (NIHR HTA) programme a new research study will investigate this issue.

In the UK, cardiac surgery uses almost ten per cent of all donor blood. Although the benefits of red cell blood transfusions for managing life-threatening bleeding are clear, the majority of decisions to transfuse after surgery are made on the basis of a patient's haemoglobin level (a measure of the ability of the blood to transport oxygen around the body). 

The level that causes a doctor to transfuse a patient varies widely and research in non-cardiac surgical fields has shown that lowering the level that 'triggers' transfusion reduces complications as well as the use of blood.

Barnaby Reeves, Professorial Research Fellow in Health Services Research at the University of Bristol and Gavin Murphy, Walport Consultant Senior Lecturer in Cardiac Surgery at University Hospitals Bristol NHS Foundation Trust will lead the study. 

The new research will examine if withholding blood transfusion until the patient reaches a lower haemoglobin 'trigger' point will improve the outcome for cardiac surgery patients and also reduce hospital costs.

The study will take the form of a randomised controlled trial at several hospitals across the UK.  Patients identified from both outpatient and in-patient waiting lists will be invited to take part in the trial before surgery takes place.

Mr Murphy explained: "Unnecessary blood transfusions increase healthcare costs both directly, because blood is an increasingly scarce and expensive resource, and indirectly, due to complications associated with transfusion. 

"Transfusion may cause complications by reducing patients' ability to fight off infection and respond to the stress that surgery puts on the body, as well as (rarely) by transmitting viral infections present in donor blood."

Professor Reeves said: "During this trial, patients whose haemoglobin level drops below the level at which transfusion is conventionally given will either be given a transfusion (more or less as they are now) or only when the haemoglobin level drops to a lower, more restrictive level.

"The primary outcome will be the number of patients affected by sepsis, stroke, heart attack or kidney failure during the first three months after surgery.

"We believe that withholding transfusion until the lower haemoglobin level is reached will reduce both complications and hospital costs."