A wearable patch the size of a postage stamp that can monitor blood pressure continuously could soon help people manage their hypertension . Researchers at the University of California, San Diego, who developed the wearable ultrasound patch report Wednesday in the journal Nature Biomedical Engineering that it has worked well in tests with more than 100 patients. Advertisement Maintaining a normal blood pressure -- 120/80 -- helps prevent many illnesses, from heart disease and stroke to kidney