Abstract: Size-specific electrical connector apparatus optimized for e.g., biomedical applications, and which prevents mating to the wrong sized terminals. In one embodiment, the connector apparatus comprises a device having a two piece assembly adapted to pivotally engage and lock a sensor such as those used in impedance cardiography (ICG). The conductor is shaped so as to provide a high degree of specificity in sensor connection as well as signal stability and reliability. In one variant, the pivot comprises a spring-loaded pivot having no external stops and the shape of a sensor engaging aperture is defined by a metal insert associated with one element of the assembly and the pivot is permanently formed within the connector. Thus, a user is obstructed from changing the properties of the connector to accept smaller or larger sensors. Methods of manufacturing and operating the connector are also disclosed. In one embodiment, an opening in the metal insert (212) is sized to exclude oversized sensors.

Abstract: An improved method and apparatus for non-invasively assessing one or more physiologic parameters, such as for example those associated with the circulatory system of a living organism. In one exemplary embodiment, the invention evaluates cardiac events (e.g., beats) present within an ECG waveform to determine which beats should be retained and which rejected. This evaluation is conducted based on a hierarchical method, wherein the ECG noise and morphology, as well as various aspects of the Delta Z (change in thoracic impedance), are utilized to evaluate beats for retention/rejection. In one variant, fuzzy models are used in conducting the foregoing evaluations. Parameter median filtering is also optionally applied. The foregoing techniques increase the accuracy, stability and robustness of any systems (e.g., impedance cardiographic or otherwise) which make use of the events. Improved impedance cardiographic apparatus and methods of treatment are also disclosed.

Abstract: An improved apparatus and method for determining the cardiac output of a living subject. The improved apparatus generally comprises one or more electrode assemblies or patches affixed to the skin of the subject in the vicinity of the thoracic cavity. In one embodiment, the apparatus comprises a constant current source impedance cardiography (ICG) monitor adapted as a stand-alone system. In another embodiment, the apparatus comprises a module adapted for use with a host monitoring system, the latter providing ECG, blood pressure, and/or other inputs to the module. Method of detecting a loss of electrical continuity in one or more of the terminals of the electrode patch, and selecting between a plurality of signal inputs based on signal quality, are also disclosed.

Abstract: Electrical connector apparatus optimized for biomedical applications. In one embodiment, the connector apparatus comprises a low-cost simplified device having a unitary conductor element adapted to interface with an electrode terminal such as used in impedance cardiography (ICG) or electrocardiography (ECG). The unitary conductor is shaped so as to provide a high degree of electrical performance and signal stability, and also be highly reliable. The simplified structure of the connector (including the use of the unitary conductor element) allows it to be manufactured for very low cost, so as to be disposable if desired. Methods of manufacturing and operating the connector are also disclosed.

Abstract: An improved apparatus and method for evaluating the need for, and performing as applicable, defibrillation. In one aspect, an improved defibrillation apparatus utilizing cardiographic impedance waveforms for determining cardiac output and accurately correlating this output to shockable or non-shockable cardiac conditions is disclosed. One exemplary embodiment uses electrodes having optimal spacing to enhance the accuracy of the impedance measurement. Another exemplary embodiment uses time-scale processing of the waveforms to identify fiducial points therein. Yet another embodiment uses advanced decision logic (such as fuzzy logic) to perform the aforementioned evaluation. The use of pacing spike detection and beat parsing based thereon is also disclosed.

Abstract: An improved method and apparatus for assessing time-variant waveforms and identifying artifacts of interest therein. In one exemplary embodiment, an iterative interval search technique is applied to ECG waveform data in order to identify one or more artifacts (e.g., right atrial and right ventricular “spikes”) within the waveform in conjunction with a fuzzy logic noise threshold analysis. This technique allows for robust artifact identification in waveforms where significant variations in noise and artifact periodicity may exist. The identified artifact(s) may then be used as an input to another process, such as being substituted as an ECG “Q” point for subsequent fiducial point detection within a cardiographic impedance waveform. Apparatus including computer programs for implementing the aforementioned techniques are also disclosed.

Abstract: An improved apparatus and method for determining the cardiac output of a living subject. The improved apparatus generally comprises one or more electrode assemblies or patches affixed to the skin of the subject in the vicinity of the thoracic cavity. The terminals of each electrode patch are in contact with an electrolytic gel, and are spaced a predetermined distance from one another within the patch. This predetermined spacing allows for more consistent measurements, and also allows for the detection of a loss of electrical continuity between the terminals of the patch and their associated electrical connectors in the clinical environment. The method generally comprises generating and passing a stimulation current through the terminals and the thoracic cavity of the subject, and measuring the impedance as a function of time.

Abstract: An improved apparatus and method for determining the cardiac output of a living subject. The improved apparatus generally comprises one or more electrode assemblies or patches affixed to the skin of the subject in the vicinity of the thoracic cavity. In one embodiment, the apparatus comprises a constant current source impedance cardiography (ICG) monitor adapted as a stand-alone system. In another embodiment, the apparatus comprises a module adapted for use with a host monitoring system, the latter providing ECG, blood pressure, and/or other inputs to the module. Method of detecting a loss of electrical continuity in one or more of the terminals of the electrode patch, and selecting between a plurality of signal inputs based on signal quality, are also disclosed.

Abstract: An improved method and apparatus for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one exemplary embodiment, the invention comprises a method of measuring cardiac output (CO) using impedance waveforms (and ECG waveforms) which are analyzed via discrete wavelet transforms. These transforms aid in identifying fiducial points within the waveforms, the fiducial points being used to calculate various parameters relating to cardiac stroke volume (such as LVET and dZ/dtmax), from which cardiac output may be determined. The use of wavelet transforms for fiducial point detection increases the accuracy of the CO determination by reducing cross-term artifact, and also significantly reduces the amount and complexity of processing required as compared to prior art time-frequency distribution or empirical techniques. Improved methods of QRS complex detection within the ECG waveform, and median filtering of an input waveform, are also disclosed.