Figure 1 Twenty four hour profile of urotensin II (U‐II) in children with congenital heart disease. U‐II concentrations at four hours after separation from cardiopulmonary bypass (CPB) were higher than at baseline and at 24 hours were lower than at baseline for all children with congenital heart disease. At all time points, U‐II was higher in children with low or normal preoperative pulmonary flow (LNF) than in children with high flow (HF). X‐Clamp, aortic cross clamp.