APAGBI Project Grant
Platelet function in paediatric cardiac patients after cardiopulmonary bypass and Extra-Corporeal Life Support (ECLS)
Dr Dannie Seddon
Background
Heart disease in babies and children is common, with around 4,600 babies born each year with heart problems. There are over 6,000 operations on children's hearts in the UK each year, and the majority of these require the support of the heart-lung machine (cardio-pulmonary bypass).
In addition to these children, there are also a number of critically unwell children who need the support of the heart-lung machine for a longer period of time, whilst their heart recovers, or in some instances whilst they wait for a heart transplant.
The heart-lung machine is associated with a number of complications, including the activation and dilution of the patient's blood. Activation leads to the blood trying to clot, and so this is overcome by giving the patient a blood thinner. The addition of the blood thinner, plus dilution mean that the patient is then prone to bleeding. The balance between clotting and bleeding is very fine, some children can have both complications at once, and these children are at a high risk of dying.
We believe that a component of the patient's blood called platelets contributes to the bleeding complications that these patients have. Platelets are an integral part of the blood and play a large part in how it clots.
The tests that look at the effects that the heart lung machine has on the platelets are difficult to perform in children because they need large volume blood samples which cannot be taken from small babies. So the mechanisms behind the blood complications are currently poorly understood.
Aims and Methodology
This study will use a new testing method which has been compared to the gold standard tests and is as sensitive in detecting problems with the patient's platelets. The advantage of this testing method is that it only uses a small volume of blood and means that we can test children and small babies. As there is currently no available data for this group of patients each patient will act as their own control. No blood tests will be taken with the child or baby awake unless they have a special kind of intravenous drip that the sample can be taken from without discomfort.
The study will be performed over a 45 month period at Birmingham Children's Hospital and Birmingham University. We aim to recruit over 200 children who have operations using the heart-lung machine, or need the longer term support. The patients' parents will be consented pre-operatively after identification from the cardiac surgical waiting lists. Patients over the age of 12 will have the opportunity to assent to the study, but formal consent will be parental.
Expected Outcomes and Limitations
Information generated from these tests will enable us to understand how the patients blood changes on the heart-lung machine, and also to be able to manage and treat these significant complications in critically unwell babies and children. In addition to this, the blood tests will provide valuable information about paediatric platelets, an area where there is very limited data currently.
