203 results about "Bio impedance" patented technology

Systems and methods for discriminating and locating tissues within a body involve applying a waveform signal to tissue between two electrodes and measuring the electrical characteristics of the signal transmitted through the tissue. At least one of the electrodes is constrained in area so that localized electrical characteristics of the tissue are measured. Such localized electrical characteristics are determined over a portion of a body of the subject by using an array of electrodes or electrodes that can be moved over the body. A controller may implement the process and perform calculations on the measured data to identify tissue types and locations within the measured area, and to present results in graphical form. Results may be combined with other tissue imaging technologies and with image-guided systems.

A method and system for discriminating tissues in a subject, particularly for identifying nerve tissue, includes a processor, a waveform generator, a waveform electrode and a return electrode and an electrical property measuring device such as a volt meter. The electrodes are applied to the skin of the subject and an electrical waveform applied to the tissue via the electrodes. A series of electrical property measurements between the electrodes yield digital data that is used to determine coefficients of an approximating mathematical function, which is then used to derived electrical properties of the tissue. Derived electrical properties are then displayed on a display device.

A method of determining an impedance of at least one lung of a patient having an implanted pacemaker that comprises first and second leads and a case, the method comprising: a) using the leads and the case to acquire at least a first and a second impedance measurement responsive to impedance of the patient's chest that are at least partially independent; and b) using the impedance measurements to determine the impedance of at least one of the lungs substantially independently of impedance of the other lung.

An active implantable medical device, in particular a pacemaker, defibrillator or cardioveter of the multisite type, including a circuit for measuring intercardiac impedance. Electrodes are placed in at least one ventricular site and one atrial site, and are connected to a circuit for the collection of cardiac signals, to detect a depolarization potential, as well as to a stimulation circuit, to apply stimulation pluses to at least some of the aforementioned sites. The measurement of a trans-pulmonary bio-impedance is obtained by injecting a current from an injection circuit (16) between the case (18) of the device and a first atrial (RA-) (or ventricular) site, and measuring a differential potential (20) between the case (18) and a point of measurement located in a second atrial (RA+) (or ventricular) site using a collection circuit. Switches are selectively operable to isolate the case (18) from the current injection and measurement of potential circuits, and to connect them to a common reference potential site, atrial or ventricular (LV-), which is distinct from the sites (RA-,RA+) to which are also connected these circuits, so as to allow a measurement of intracardiac impedance from the signal delivered by the differential potential measuring circuit. The switching is obtained by connections to an electric ground, operating independently of the current injection circuit and the differential potential measuring circuit.

The disclosure describes a wearable, low-cost and low-power Electrical Impedance Tomography system for gesture recognition. The system measures cross-sectional bio-impedance using electrodes on wearers' skin. Using all-pairs measurements, the interior impedance distribution is recovered, which is then fed to a hand gesture classifier. This system also solves the problem of poor accuracy of gesture recognition often observed with other gesture recognition approaches.

Implantable medical devices and techniques are implemented that use bio-impedance to measure aspects of patient physiology. A signal separation method is performed at least in part in an implantable device. The method involves detecting a plurality of impedance signals using a plurality of implantable electrodes coupled to the implantable device. The method further involves separating one or more signals from the plurality of impedance signals using a signal separation technique, such as an algorithm-based separation technique.

A passive element is provided to facilitate passive detection of analytes, such as analytes, using an electromagnetic probe beam. The probe beam may be provided by a radar and/or lidar system. In one example, a passive element comprises a reference dipole and a detection dipole, the detection dipole having an associated analyte-sensitive element, such as a chemoresistive or bioresistive element. When the analyte-sensitive element is in a modified conducting state due to the presence of an analyte, the detection cross section is modified whereas a reference cross section is substantially unchanged by the presence of the analyte. A passive element may comprise a frequency selective surface, for example including a frequency-selective surface (FSS) embedded in a dielectric layer and using an analyte-sensitive impedance layer to modify the electromagnetic absorption properties, allowing analyte detection.

A method for measuring the impedance of a portion of a subject, by passing a known current provided by a current source unit between a first pair of electrodes contacting the skin surface of the subject. The measuring of a voltage with a voltage measuring instrument, between at least one second pair of electrodes contacting the skin surface of the subject when the current source unit is passing the known current through the first pair of electrodes; calculating the bio-impedance of the portion of the subject based on the known current and the calibrated voltage.

The present invention relates to a method for determining the posture of a patient. The method comprises the steps of: initiating (50, 52) a patient posture determining session by performing an electrical bio-impedance measurement session in at least one of a number of different electrode configurations in order to measure an impedance value for the at least one configuration; obtaining reference impedance values (54) stored in advance for the at least one configuration and for at least one potential posture of the patient; comparing (54) the measured impedance value for the at least one configuration with corresponding stored reference impedance values for at least one potential posture of the patient; and determining (56) the present posture of the patient by using results from the comparison between measured impedance values and the stored reference impedance values. Furthermore, the invention relates to a medical device for determining the posture of a patient and a computer readable medium comprising instructions for bringing a computer to perform the inventive method.

An active implantable medical device having a plurality of connection terminals able to be connected to electrodes placed in at least three distinct respective sites in a myocardium; circuits for measuring an intracardiac bio-impedance, comprising circuits for injecting a current and circuits for collecting a voltage at respective poles of a configuration of said connection terminals, and circuits able to deliver at an output a dynamic impedance signal that is a function of the injected current and the collected voltage; and circuits for evaluating an intracardiac volume, receiving at in input the impedance signal and delivering at an output a dynamic value of volume representing an instantaneous absolute value of intracardiac volume.

Embodiments of synchronous detection circuits and methods are provided for extracting magnitude and phase information from a waveform. One embodiment of a synchronous detection circuit includes a driver circuit, an analog-to-digital converter (ADC) and a controller. The driver circuit is configured to supply an input waveform at an input frequency to a load. The ADC is coupled to receive an output waveform from the load, and configured for generating four digital samples, each spaced 90° apart, for every period of the output waveform. The controller is configured for setting an oversampling rate (OSR) of the ADC, so that the ADC generates an integer number, M, of sub-samples for each digital sample generated by the ADC, where the integer number, M, of sub-samples is inversely proportional to the input frequency of the input waveform. The controller is further configured to use the digital samples generated by the ADC to extract magnitude and phase information from the output waveform.

Electrodes for a bio-impedance measuring device or a body composition monitor, the electrodes being integral with or being attached to a surface of at least one device belonging to a group of electronic and/or non-electronic devices used in the preparation of a dialysis treatment or during dialysis, in particular during peritoneal dialysis, the group preferably consisting of organizers of a continuous ambulatory peritoneal dialysis system (CAPD), automated peritoneal dialysis devices, automated peritoneal dialysis-cyclers (APD-Cycler), bioelectrical impedance analyzers (BIA), body composition monitors (BCM), hand-held electrodes holders for the electrodes, and dialysis apparatuses. Devices and methods used during dialysis are also described.