Continuous blood pressure measurement with ultrasound.

Cardiovascular diseases are the main cause of death in Germany. A long-term blood pressure measurement is crucial to identify hypertension which can lead to cardiovascular disease. Conventional techniques use the automatic arm cuff method which is painful and provides only intermittent results. A new method for continuous measurement is developed using a DOPPLER ultrasound sensor on a superficial artery and a small balloon. A voice coil actuator is used to change the balloon pressure using a control loop. Holding the control variable – the ultrasound signal – constant and low by controlling the balloon pressure permits a continuous measurement. The system was tested using a blood pressure simulator with variable pressure curves and abrupt pressure changes. The controller-induced balloon pressure tracks the pressure in the model artery very closely.