Effect of cardiopulmonary bypass and surgical intervention on the natriuretic hormone system in children

Objectives: We sought to determine the effect of cardiopulmonary bypass and surgical intervention on the natriuretic hormone system in children and to assess whether such changes are associated with morbidity. Methods: At 6 perioperative time points in 25 patients, plasma levels of atrial natriuretic peptide, brain natriuretic peptide, and guanosine 3′, 5′- monophosphate were measured, and the biologic activity of the natriuretic hormone system was quantified. Relationships were sought between changes in brain natriuretic peptide levels, biologic activity, and a number of morbidity indicators. Results: There was a significant change in atrial natriuretic peptide levels (P = .037), brain natriuretic peptide levels (P = .001), and biologic activity of the natriuretic hormone system (P = .009) over the first 4 time points in the study. Atrial natriuretic peptide levels transiently decreased from baseline to 12 hours after surgical intervention. Compared with baseline values, brain natriuretic peptide levels were increased at 12 hours after surgical intervention and on postoperative day 1. The increase in brain natriuretic peptide levels from baseline to 12 hours after surgical intervention was associated with cardiopulmonary bypass time (r_s = 0.4, P = .047). The biologic activity transiently decreased from baseline to intensive care unit admission but was not associated with any morbidity indicators. Conclusions: Increased postoperative brain natriuretic peptide levels are associated with longer bypass times. The biologic activity of the natriuretic hormone system is transiently impaired. Larger studies should investigate brain natriuretic peptide as a predictor of postoperative morbidity and the potential for natriuretic hormone infusions to improve postoperative hemodynamics and urine output.