For non-invasive hemodynamic monitoring, DYNEMO 3000 (SOMETEC Inc) has a 10 mHz ultrasonic echo scan and a 5 mHz Doppler velocimeter connected to an echo-oesophageal probe allowing continuous measurement of the aortic diameter and of the blood flow velocity in the descending aorta. This device thus can only measure the aortic blood flow, but also calculate the stroke volume and the systemic vascular resistance. Moreover, the systolic time intervals and the length of the pre-ejection period can be measured with the oscillometric tensiometer and the electrocardiography. This paper describes a case in which this device was used for a child with coarctation of the aorta. The hemodynamic changes were measured continuously during coarctectomy. During the temporary bypass, the aortic blood flow and the stroke volume decreased, but on the other hand, the total vascular resistance increased at the same time. After the bypass, these parameters returned to the values before the bypass. We think that this device is useful as a non-invasive monitor to observe the hemodynamic changes continuously during operation for a child with congenital heart disease.