A FEMALE neonate, weighing 2,690 g, developed severe cyanosis immediately after birth, and was diagnosed as having complex heart anomaly (truncus arteriosus, interruption of aortic arch, aortopulmonary septal defect, patent ducts arteriosus, and persistent foramen ovale). Despite support with dopamine, dobutamine, and epinephrine, congestive heart failure developed. Therefore, total correction surgery was scheduled to take place on the patient's twenty-first day of life. Anaesthesia was induced and maintained with fentanyl (25 μg/kg) and midazolam (0.3 mg/kg). Surgery was performed under the moderately hypothermic (25°C) cardiopulmonary bypass (CPB) with a total flow of 2.8 l.min -1 .m 2 , CPB was started 55 min after the anesthetic induction. The interval from the start of CPB to the initial attempt to wean the patient from CPB with sufficient body temperature recovery (36.2°C) was 5 h and 20 min. The attempt was made to discontinue CPB with the aid of dopamine (4 - 8 μg.kg -1 .min -1 ) and dobutamine (5-8 μg.kg -1 .min -1 ). However, decreasing the bypass flow to less than 1.5 l.min -1 .m -2 resulted in sustained hypotension. Adding epinephrine (0.5 μg/kg/min) and isoproterenol (0.1 μg.kg -1 .min -1 ) did not improve the patient's hemodynamics; her systemic mean arterial pressure while still on partial bypass was ≤ 30 mmHg, while her central venous pressure (CVP) was approximately 17 mmHg. The addition of an infusion of milrinone (0.5 (μg.kg -1 .min -1 ) for approximately 40 min also had no significant effect. Echocardiography (using an epicardial probe) showed an adequate surgical repair. At this point, with the patient back on full bypass support all inotropic agents were discontinued. We next administered a combination of colforsin dalopate HCI (0.25 μg.kg -1 .min -1 ') and dopamine (5 μg.kg -1 .min -1 ). The patient's CPB flow rate decreased to 1.0 l.min -1 .m -2 and CVP was controlled at 8-11 mmHg. Over the next 30 min, the patient's mean arterial pressure increased from 35 to 65 mmHg, and her heart rate increased from 140 to 170 beats/min. After approximately 20 min of stable conditions, CPB was successfully discontinued. Her postweaning hemodynamic parameters showed heart rate, mean systemic arterial pressure, and CVP levels in the ranges of 170-180 beats/min, 55-65 mmHg, and 11-13 mmHg, respectively, Arterial blood gas analysis did not show metabolic acidosis, hypercarbia, or hypoxemia, The surgery terminated 2 h after the CPB weaning, Hemodynamic parameters recorded after each attempt to discontinue bypass are summarized in table 1. After being transferred to the intensive care unit, the patient's heart rate continued to increase, reaching 190 beats/min. Her colforsin infusion was discontinued while dopamine was maintained. Two hours later, her mean arterial pressure decreased to 35 mmHg from 60 mmHg, her heart rate decreased to 140 beats/min from 170 beats/min, and CVP increased from 11 mmHg to 17 mmHg. An infusion of epinephrine was added, but without success. Therefore, approximately 1 h later, colforsin dalopate HCl infusion (0.25 μg.kg -1 .min 1 ) was restarted. Mean arterial pressure and heart rate quickly increased to 65 mmHg and 178 beats/min, respectively. Colforsin was discontinued without difficulty 5 h later.