Philips dreams up underwear-infused blood pressure monitoring system

Wearable Monitoring System

This invention relates to monitoring systems adapted for continuously or at least regularly monitoring the vital signs of a subject, and particularly to a system for measuring blood pressure.

In all developed countries, car dio -vascular diseases like myocardial infarction, congestive heart failure or hypertension have an increasing impact on mortality and morbidity. There is an increasing demand for long term continuous monitoring of a patient's vital signs, which offers the opportunity to evaluate the performance of the cardio -vascular system. Various different blood pressure measurement systems have commonly been used in the past, which require a pressurised cuff or similar device which must be specially attached to the patient when a measurement is to be taken, and also require a suitably skilled clinician to operate them.

Consequently such devices are usually confined to uses in a doctor's premises or in hospital, for example, and are not adapted for continuous or regular monitoring purposes. Accordingly the present invention seeks to provide a blood pressure measuring system, which utilises Pulse Transit Time methodology for deriving measurements from detected signals such as the ECG, and can also be used for monitoring other vital signs. It is particularly suitable for implementation in a continuously wearable undergarment with integrated measuring sensors or electrodes, so as to be directly in contact with the subject's skin. Preferably the garment includes at least four electrodes in order to allow PTT measurements to be made without additional connections to the patient's body.

Preferably the sensors are of a type which do not require special attachment systems, gels or pastes to make proper electrical contact, for example they -->may be dry electrodes of a type recently developed, made from conductive rubber, which rely only on naturally-produced sweat to make a conductive bridge between the skin and the electrode. Preferably, the undergarment comprises underpants having electrodes arranged internally, at least in the waistband area. Preferably, electrodes are so arranged as to measure the passing of pulses of the central artery, and the left and right femoralis, as well as the ECG.