Patent US 5,406,953

An instrument for measuring the blood pressure and for checking the heart rate. It comprises of an electronic circuit for detecting, filtering, and amplifying the full steam of Korotkoff sounds which is produced as electrical signals from an acoustic pickup applied to the brachial artery. Korotkoff sounds are heard directly via the instrument's loud speaker, thus eliminating the need for the conventional stethoscope. Evaluation of blood pressure is easily and efficiently carried out by an individual with little skill or training and without the aid of a second person.