Introduction At Children's Healthcare of Atlanta, thousands of children are seen in the Emergency Department (ED) each year for evaluation and treatment. Deciding if a child has a cardiac or pulmonary problem can be very difficult, especially in infants. Early recognition of cardiac disease can significantly impact the physician's ability to provide appropriate treatment, make necessary interventions, and affect patient outcome. An accurate laboratory marker of cardiac disease for pediatric Emergency Medicine does not exist. B-Type Natriuretic Peptide (BNP) is a hormone produced by the ventricular myocardium (heart muscle) in response to increased myocardial demands. It has been used extensively in the adult population to evaluate patients for heart disease, and has been demonstrated to be very accurate in the differentiation of heart disease from lung disease in the adult Emergency Department (1,2,3).

There is increasing experience with BNP in pediatrics for the evaluation of heart disease, primarily in patients with congenital heart disease (4, 5, 6). The normal BNP level is less than 100 pg/ml, slightly higher in neonates. Patients who present to the ED and are diagnosed with heart disease are often admitted to the Cardiac Intensive Care Unit (CICU) for further management and stabilization. Part of the initial evaluation is a BNP level. These patients usually have marked elevation of the BNP levels in the 2000-5000 pg/ml range upon admission. The level varies with the type and severity of their heart disease. However very little is known about the non-cardiac ED patient BNP level. To utilize BNP as an accurate marker of cardiac disease in the pediatric ED, a clear difference between cardiac and non-cardiac patients needs to be demonstrated. If a large difference in BNP levels exists for the pediatric patient with heart disease who presents to the ED when compared to the child who presents to the ED with other non-cardiac disease processes, a useful marker of heart disease in children would be demonstrated.

Objectives The objective of the proposed research is to determine the typical BNP level in non-cardiac pediatric patients who present to the ED for evaluation of respiratory and/ or infectious processes. The endpoint of the project will be the collection of BNP levels from 100 patients less than 6 years of age.

Hypothesis 1 (H1) BNP levels for children with non-cardiac disease will be in the normal range (< 100pg/ml), and can be easily distinguished from the elevated levels seen in children with congenital or acquired heart disease.