In cases involving single ventricles, predicting streaming characteristics is difficult. Unfavorable streaming can cause decreased oxygen saturation. Judging whether desaturation results from decreased pulmonary flow or unfavorable streaming is critical. A 20-day-old infant with a single left ventricle underwent ductus arteriosus ligation and pulmonary artery banding to control high pulmonary flow. Severe desaturation presented postoperatively, which worsened to 68% despite pure-oxygen ventilation. A bedside contrast echocardiogram helped determine whether unfavorable streaming caused desaturation. It revealed systemic venous streaming predominantly directed to the aorta. Emergent balloon atrial septostomy facilitated mixing at the atrial level. Oxygen saturation promptly increased to 85%.
Keywords: Admixture; Congenital cardiac disease; Echocardiogram; Echocardiography; Ultrasound; Unfavorable streaming.