Abstract: An apparatus a method for determining stroke volume by bioimpedance from a person having two or more spaced apart alternating current flow electrodes positionable on a person and two or more spaced apart voltage sensing electrodes positionable on the person and between the alternating current flow electrodes. A constant magnitude alternating current source is electrically connectable to the alternating current flow electrodes. A voltmeter is electrically connectable to the voltage sensing electrodes and configured to generate a voltage signal Z from a voltage sensed by the voltage sensing electrodes. A processing unit is electrically connectable with the voltmeter and configured to determine a stroke volume (SV) using the voltage signal Z and at least one of six equations.

Abstract: An apparatus a method for determining stroke volume by bioimpedance from a person having two or more spaced apart alternating current flow electrodes positionable on a person and two or more spaced apart voltage sensing electrodes positionable on the person and between the alternating current flow electrodes. A constant magnitude alternating current source is electrically connectable to the alternating current flow electrodes. A voltmeter is electrically connectable to the voltage sensing electrodes and configured to generate a voltage signal Z from a voltage sensed by the voltage sensing electrodes. A processing unit is electrically connectable with the voltmeter and configured to determine a stroke volume (SV) using the voltage signal Z and at least one of six equations.

Abstract: An apparatus and method for determining stroke volume by bioimpedance from a person that includes two or more spaced apart alternating current flow electrodes positionable on a person's forearm, two or more spaced apart voltage sensing electrodes positionable on the person's forearm and between the alternating current flow electrodes, an alternating current source providing an alternating current to the current flow electrodes, a voltmeter configured to generate a voltage signal from a voltage sensed by the voltage sensing electrodes, and a processing unit configured to determine a stroke volume (SV) using the voltage signal and at least one of two equations that include, among other terms, the person's weight, a peak time rate of change of a transradioulnar impedance pulse variation (dZ/dtmax), a transradioulnar quasi-static base impedance (Z0), a systolic flow time (TSF), and a volume conductor (Vc).

Abstract: In order to reliably determine the left-ventricular ejection time TLVE of a heart of a subject, at least two different measuring methods are employed. This includes in any case the derivation of a first waveform related to thoracic electrical bioimpedance or bioadmittance. A second waveform can be determined by using pulse oximetry, Doppler velocimetry, measurement of arterial blood pressure and measurement of peripheral electrical bioimpedance or bioadmittance. Depending on signal quality, the results obtained by each method are weighted and then averaged. The weighted average for left-ventricular ejection time is used as an input variable for cardiovascular monitoring methods, which determine objective measurements of cardiovascular function and performance. Such measurements include, but are not limited to, left ventricular ejection fraction, stroke volume, cardiac output, systolic time ratio, and indices of ventricular contractility.

Abstract: In order to reliably determine the left-ventricular ejection time TLVE of a heart of a subject, at least two different measuring methods are employed. This includes in any case the derivation of a first waveform related to thoracic electrical bioimpedance or bioadmittance. A second waveform can be determined by using pulse oximetry, Doppler velocimetry, measurement of arterial blood pressure and measurement of peripheral electrical bioimpedance or bioadmittance. Depending on signal quality, the results obtained by each method are weighted and then averaged. The weighted average for left-ventricular ejection time is used as an input variable for cardiovascular monitoring methods, which determine objective measurements of cardiovascular function and performance. Such measurements include, but are not limited to, left ventricular ejection fraction, stroke volume, cardiac output, systolic time ratio, and indices of ventricular contractility.

Abstract: In order to reliably determine the left-ventricular ejection time TLVE of a heart of a subject, at least two different measuring methods are employed. This includes in any case the derivation of a first waveform related to thoracic electrical bioimpedance or bioadmittance. A second waveform can be determined by using pulse oximetry, Doppler velocimetry, measurement of arterial blood pressure and measurement of peripheral electrical bioimpedance or bioadmittance. Depending on signal quality, the results obtained by each method are weighted and then averaged. The weighted average for left-ventricular ejection time is used as an input variable for cardiovascular monitoring methods, which determine objective measurements of cardiovascular function and performance. Such measurements include, but are not limited to, left ventricular ejection fraction, stroke volume, cardiac output, systolic time ratio, and indices of ventricular contractility.

Abstract: In order to reliably determine the left-ventricular ejection time TLVE of a heart of a subject, at least two different measuring methods are employed. This includes in any case the derivation of a first waveform related to thoracic electrical bioimpedance or bioadmittance. A second waveform can be determined by using pulse oximetry, Doppler velocimetry, measurement of arterial blood pressure and measurement of peripheral electrical bioimpedance or bioadmittance. Depending on signal quality, the results obtained by each method are weighted and then averaged. The weighted average for left-ventricular ejection time is used as an input variable for cardiovascular monitoring methods, which determine objective measurements of cardiovascular function and performance. Such measurements include, but are not limited to, left ventricular ejection fraction, stroke volume, cardiac output, systolic time ratio, and indices of ventricular contractility.

Abstract: Provided herein are methods and apparatus for stroke volume determination by bioimpedance from a patient's upper arm, or brachium, or a patient's thorax, utilizing pulsations of the arteries contained therein. The apparatus includes two or more spaced apart alternating current flow electrodes positioned on the patient's arm or thorax and two or more spaced apart voltage sensing electrodes positioned on the patient's arm or thorax and in-between alternating current flow electrodes. The system and method utilizes the mean value of the second time-derivative of the cardiogenically induced impedance variation of the patient using the measured voltage from the voltage sensors in calculating the stroke volume of the patient.

Abstract: Provided herein are methods and apparatus for stroke volume determination by bioimpedance from a patient's upper arm, or brachium, or a patient's thorax, utilizing pulsations of the arteries contained therein. The apparatus includes two or more spaced apart alternating current flow electrodes positioned on the patient's arm or thorax and two or more spaced apart voltage sensing electrodes positioned on the patient's arm or thorax and in-between alternating current flow electrodes. The system and method utilizes voltage sensed by the voltage sensing electrodes to calculate a cardiogenically induced impedance variation value of the patient, and to determine a stroke volume of the patient by multiplying the cardiogenically induced impedance variation value by a volume conductor VC and by a left ventricular ejection time TLVE.

Abstract: Provided herein are methods and apparatus for stroke volume determination by bioimpedance from a patient's upper arm, or brachium, or a patient's thorax, utilizing pulsations of the arteries contained therein. The apparatus includes two or more spaced apart alternating current flow electrodes positioned on the patient's arm or thorax and two or more spaced apart voltage sensing electrodes positioned on the patient's arm or thorax and in-between alternating current flow electrodes. The system and method utilizes voltage sensed by the voltage sensing electrodes to calculate a cardiogenically induced impedance variation value of the patient, and to determine a stroke volume of the patient by multiplying the cardiogenicaly induced impedance variation value by a volume conductor VC and by a left ventricular ejection time TLVE.

Abstract: Doppler Velocimetry is a widely used method for estimating stroke volume (SV). The accuracy and reliability of its measurement however, is dependant on a) the correct assessment of the aortic valve cross-sectional area (CSA), and b) the maximal systolic velocity integral (SVI). The invention avoids the conventional assessment of aortic valve CSA by using a calibration method: a reference stroke volume SVREF is determined by a method different from Doppler velocimetry, e.g. by thoracic electrical bioimpedance (TEB), or thoracic electrical bioadmittance, measured via surface thorax electrodes (transthoracic approach) or via electrodes located directly on an esophageal catheter/probe (esophageal approach). In the latter case, if esophageal Doppler velocimetry is used, the same catheter can be used for the placement of the electrodes and for an ultrasound transducer.

Abstract: In order to reliably determine the left-ventricular ejection time TLVE of a heart of a subject, at least two different measuring methods are employed. This includes in any case the derivation of a first waveform related to thoracic electrical bioimpedance or bioadmittance. A second waveform can be determined by using pulse oximetry, Doppler velocimetry, measurement of arterial blood pressure and measurement of peripheral electrical bioimpedance or bioadmittance. Depending on signal quality, the results obtained by each method are weighted and then averaged. The weighted average for left-ventricular ejection time is used as an input variable for cardiovascular monitoring methods, which determine objective measurements of cardiovascular function and performance. Such measurements include, but are not limited to, left ventricular ejection fraction, stroke volume, cardiac output, systolic time ratio, and indices of ventricular contractility.

Abstract: Doppler Velocimetry is a widely used method for estimating stroke volume (SV).

Abstract: The invention relates to an apparatus and a method for determining an approximate value for the stroke volume and the cardiac output of a person's heart. The apparatus and method employ a measured electrical impedance, or admittance, of a part of a person's body, namely, the thorax. This part of a person's body is chosen because its electrical impedance, or admittance, changes with time as a consequence of the periodic beating of the heart. Accordingly, the measured electrical admittance or impedance can provide information about the performance of the heart as a pump.

Abstract: The invention relates to an apparatus and a method for determining an approximate value for the stroke volume and the cardiac output of a person's heart. The apparatus and method employ a measured electrical impedance, or admittance, of a part of a person's body, namely, the thorax. This part of a person's body is chosen because its electrical impedance, or admittance, changes with time as a consequence of the periodic beating of the heart. Accordingly, the measured electrical admittance or impedance can provide information about the performance of the heart as a pump.