ProCalcitonin in the Pediatric Surgical Patient, Evaluation of a New Marker of Infection

In this research study, we want to look at the difficulty in identifying infections in children who have heart surgery. We also want to look at differentiating between actual infections and the normal post-surgery course that patients go through. We use a number of tools in the Intensive Care Unit to pick out children at risk for an infection. These tools are the physical examination, a fever, white blood cell count, and C-reactive Protein (CRP) level. When a patient has an infection, they usually have a fever, have a high white blood cell count, and have an increased CRP level. However, these are not always correct. The identification of infection remains a challenge and the laboratory markers of infection (white blood cell count and CRP) that are used now are not perfect.

A new marker of infection, Procalcitonin (PCT), has been found and has been tested in adults and children. PCT has recently been approved by the Food and Drug Administration (FDA) as a marker of infection. PCT has been shown to be a more accurate marker of infection for some groups of patients.

Prior work on a small number of children shows that PCT increases shortly just from heart surgery itself, even without infection. There is little information published about how accurate PCT is for identifying infection in the child heart population. In order to use PCT in our patients, we need to know what the normal levels of PCT are after surgery. Thus, when an infection does happen, we can identify it. We also need to take PCT levels when patients are thought to have infections. We will then need to watch for an infection over the next few days to see if the PCT level rises and can actually predict the presence an infection.

Goals:

1. Determine the Procalcitonin response to cardiopulmonary bypass in children undergoing open-heart surgery. Cardiopulmonary bypass causes a pro-inflammatory state in the patient, and associated rise in Procalcitonin. The ability to use PCT as a marker for infection will require knowledge of its typical response to bypass and the time course to return to baseline.
2. Determine the accuracy of Procalcitonin as a marker of infection, and to compare and contrast these findings with currently used laboratory markers.