Plasma neuropeptide Y and catecholamines in pediatric patients undergoing cardiac operations

Objective: Our objective was to assess the sympathoadrenal response in pediatric patients undergoing repair of congenital cardiac defects. Methods: Plasma catecholamine (norepinephrine and epinephrine) and neuropeptide Y concentrations were quantified before and after cardiopulmonary bypass to assess the response to cardiopulmonary bypass. To determine the response to aortic occlusion, levels of plasma catecholamines and neuropeptide Y were measured at the time of and immediately after release of the aortic crossclamp. Results: During cardiopulmonary bypass, no significant change in levels of plasma norepinephrine (n = 43), epinephrine (n = 37), or neuropeptide Y (n = 46) was observed. Aortic occlusion induced a significant increase in plasma neuropeptide Y, but not in catecholamines. There was a greater increase in plasma neuropeptide Y in children older than age 1 year than in those younger than 1 year. Conclusions: Plasma neuropeptide Y may be a useful marker of sympathetic nervous system activity. Children younger than age 1 year showed a lesser sympathetic response compared with the response in older children. (J Thorac Cardiovasc Surg 1997;113:278-84)