Cardiac surgery requiring use of a heart-lung machine, also known as cardiopulmonary bypass (CPB) can induce abnormalities in blood coagulation (clotting) that lead to excessive blood loss during and after operation. While of significant concern in adults, this problem takes on even greater importance in children due to the simple fact that they have a smaller blood volume. It is well known that if a child has previously undergone a heart operation, they are at increased risk of bleeding should more cardiac surgery be required ("reoperation"). The processes regulating blood coagulation are extraordinarily complex, and little is known about the exact mechanisms that contribute to the increased bleeding associated with cardiac reoperation in children. Rotational thromboelastometry (ROTEM®) is a technology that can provide, at the bedside, detailed information about coagulation abnormalities. While not currently approved for general use in the United States, in Europe ROTEM® has been used to guide administration of the blood products in surgery based upon determination of specific coagulation abnormalities. Importantly, there is now evidence that guidelines for transfusion therapy based on ROTEM® reduce transfusion requirements thus decreasing patient exposure to blood products. Whether the use of ROTEM® has potential benefit for pediatric cardiac surgical patients has not been studied. Accordingly, the present study was designed to provide preliminary data comparing coagulation profiles between children undergoing cardiac reoperation to those having primary procedure.

The investigators hypothesize that ROTEM® analysis will detect a pattern of impaired coagulation in children undergoing reoperation. The overall objective of the four assays of ROTEM® analysis therefore, is to provide information that can be used to devise a rational transfusion protocol for pediatric cardiac surgical subjects.

Specific aims of the proposed pilot studies are to:

1. Use bedside blood analysis with ROTEM® in pediatric cardiac surgical patients to provide preliminary information on the nature of coagulation abnormalities.
2. Compare ROTEM® coagulation profiles between subjects having primary surgery and those undergoing reoperation.

In order to test the study hypothesis, pediatric subjects scheduled to undergo cardiac surgery involving CPB will be recruited for two study groups: a) primary surgery; b) reoperation. For each group, a small amount of blood will be obtained for ROTEM® analysis after induction of anesthesia but before skin incision and again following Cardiopulmonary Bypass, 5 minutes after protamine administration.

Inclusion Criteria:

• Patients with congenital heart disease undergoing cardiac surgery needing cardiopulmonary bypass.
• Males and females
• Age 1 year to 6 years
• Informed consent obtained

Exclusion Criteria:

• Known pre-existing haemostatic abnormalities
• Emergency surgery
• Pre-operative treatment with prostaglandin infusion or any other medication known to interfere with platelet function or cause coagulation abnormalities .
• Inclusion in another clinical research study
• Refusal or inability of patient's parent to sign the Informed Consent Form in English.

Minors from the ages 1-6 years old receiving cardiac surgery using a cardiopulmonary bypass machine

There is no plan to share IPD