Method and device for detecting occlusion/reopening of an artery and system for measuring systolic blood pressure

An occlusion and/or reopening of an artery of a body caused by a changing pressure applied on the artery is detected. The systolic blood pressure of an artery of a body is also measured. A Doppler Ultrasound transducer attached to the exterior of the body outputs a blood flow signal indicative of a change of the blood flow in the artery caused by the changing pressure. At least one variable of a first variable indicative of the magnitude of the blood flow and a second variable indicative of the periodicity of the blood flow is derived from the blood flow signal. The occlusion and/or reopening of the artery is detected on the basis of the at least one variable. In this way, the occlusion/reopening of the artery can be detected automatically. Since the need to manually detect the occlusion and reopening of the artery by listening with a stethoscope or a Doppler probe is eliminated, the detecting result is more predictable and repeatable, and therefore also more accurate.