In this study the focus will be on correlating the levels of platelet activation markers (proteins that are released when blood cells are activated)to the duration of cardiopulmonary bypass, temperature during cardiopulmonary bypass and the weight of the patient.

This research is being done because we would like to learn more about platelet dysfunction in children undergoing cardiopulmonary bypass.

It has been an established fact that cardiopulmonary bypass causes dysfunction in platelets. Activation of platelets during cardiopulmonary bypass is implicated as being a major factor in causing platelet dysfunction.

For all participants, approximately 3.15 ml of blood will be collected in special tubes called CTAD tubes, before and after cardiopulmonary bypass (6.30ml in total). This amount of blood draw is well within the guidelines of NIH (National Institute of Health).

Enzyme-linked immunosorbent assay (ELISA) will be performed using this plasma to make quantitative assessment of Platelet factor 4 and Transforming growth factor beta.

Inclusion Criteria:

• Patients scheduled to have surgery involving cardiopulmonary bypass for congenital cardiac abnormalities.
• Age: Newborn to 7 years
• Gender: male and female

Exclusion Criteria:

• Emergency surgery
• Weight less than 3 kg
• Age greater than 7 years
• Patients with low platelet counts (<100,000)
• Patients on medications that are known to interfere with platelet function such as prostacyclins, non-steroidal anti-inflammatory drugs, plavix.

Patients whose parents not willing to give consent

The targeted population will be pediatric patients with congenital heart defects who will be needing cardiopulmonary bypass (CPB) while undergoing cardiac surgery. The age range will be newborn to 7 years of age.