A Novel Automatic Method to Determine Blood Pressure Based on Thresholds of Audibility

Abstract

We present a novel system which intends to avoid a current limit presented by the commonly adopted method to measure the diastolic and systolic blood pressure. In particular, the system allows acquiring the measurements without bothering the patient, as is with the traditional inflatable cuff necessary to restrict blood flow. In such a way, it is possible to realize a holter system that is free from the inconvenience to wake up the patient during nighttime. With an ensemble of one simple pressure sensor, one audio-frequency microphone (adopted as recommended in literature references) and a low-cost ad-hoc designed electronic circuitry, we derived data from experiments involving 20 patient records, realized in two different days. Data allowed recognizing a Gaussian relationship between pressure and audio signals. This relationship enables taking advantage from the Korotkoff sound to determine the diastolic and systolic blood pressure values.