APPARATUS FOR OBTAINING CARDIOVASCULAR INFORMATION BY MEASURING BETWEEN TWO EXTREMITIES

摘要

An apparatus for obtaining information on a cardiovascular system based exclusively on measurements between two limbs and effected with a pair of distal electrodes on each limb. The measurement is made by causing an alternating current to flow between one electrode of each limb and measuring the potential difference between the other two electrodes, one also on each limb. This potential difference has a low frequency component which is an electrocardiogram (ECG) and another component having a frequency of the injected alternating current and from which an impedance plethysmogram (IPG) is extracted. The cardiovascular information is determined by measuring the time interval between any predefined characteristic element of the ECG and IPG.

主权项

1. An apparatus for obtaining information on a cardiovascular system, comprising:
a) only two pairs of electrodes, each pair on a respective limb, one electrode of each pair being a measuring electrode and the other electrode of each pair being a current injector electrode; b) an alternative current source to provide an alternating current having a frequency to the current injector electrodes; c) a device for measuring potential differences in voltage including a detector to separate, from the measured potential differences, a first component corresponding to an electrocardiogram, and a second component having the frequency of said alternating current, wherein the second component has an impedance including a continuous component and a variable component, said variable component corresponding to an impedance plethysmogram; d) a separator for separating said continuous component from said variable component, e) a digitizer to digitize said first component and said variable component, f) an identifier to identify predefined elements in each of said first component and said variable component, respectively; g) a calculator to calculate a propagation time of a pulse wave by measuring time intervals between said predefined elements; and h) an estimator to estimate the cardiovascular system information from said measured time intervals.