Abstract: An external defibrillator estimates the phase of ventricular defibrillation (VF) by deriving, from an ECG exhibiting VF, at least one quality marker representing the morphology of the ECG and, therefore, the duration of the VF. The duration of the VF is calculated as a function of the value (s) of the quality marker (s). The quality marker (s) may comprise any one or more of the median slope of the ECG, the average slope of the ECG, the ratio of the power in relatively high and low frequency bands of the ECG, and a measure of the density and amplitude of peaks in the ECG, over a predetermined period.

Abstract: An external defibrillator estimates the phase of ventricular defibrillation (VF) by deriving, from an ECG exhibiting VF, at least one quality marker representing the morphology of the ECG and, therefore, the duration of the VF. The duration of the VF is calculated as a function of the value (s) of the quality marker (s). The quality marker (s) may comprise any one or more of the median slope of the ECG, the average slope of the ECG, the ratio of the power in relatively high and low frequency bands of the ECG, and a measure of the density and amplitude of peaks in the ECG, over a predetermined period.

Abstract: There is provided a chest-based oximeter for measuring oxygen saturation of hemoglobin in blood of the chest of a subject, including at least one radiation source adapted to emit radiation onto the chest, at least one radiation detector adapted to detect radiation reflected from the chest, and a pressure device adapted to apply pressure to the oximeter to connect the oximeter to the chest.

Abstract: An external defibrillator estimates the phase of ventricular defibrillation (VF) by deriving, from an ECG exhibiting VF, at least one quality marker representing the morphology of the ECG and, therefore, the duration of the VF. The duration of the VF is calculated as a function of the value (s) of the quality marker (s). The quality marker (s) may comprise any one or more of the median slope of the ECG, the average slope of the ECG, the ratio of the power in relatively high and low frequency bands of the ECG, and a measure of the density and amplitude of peaks in the ECG, over a predetermined period.

Abstract: A cardiopulmonary resuscitation (CPR) compression force indicator includes circuitry (20, 26, 28, 30) for monitoring a patient's transthoracic impedance while the patient is being given CPR and generating a corresponding impedance signal, circuitry (32, 34, 36) for processing the impedance signal to provide an ongoing measurement of cardiac hemodynamic output, a microprocessor (24) for determining if the measurement falls outside pre-set limits, and indicator(s) (38) for indicating such determination externally to the person giving the CPR.

Abstract: An external defibrillator estimates the phase of ventricular defibrillation (VF) by deriving, from an ECG exhibiting VF, at least one quality marker representing the morphology of the ECG and, therefore, the duration of the VF. The duration of the VF is calculated as a function of the value (s) of the quality marker (s). The quality marker (s) may comprise any one or more of the median slope of the ECG, the average slope of the ECG, the ratio of the power in relatively high and low frequency bands of the ECG, and a measure of the density and amplitude of peaks in the ECG, over a predetermined period.

Abstract: An external defibrillator estimates the phase of ventricular defibrillation (VF) by deriving, from an ECG exhibiting VF, at least one quality marker representing the morphology of the ECG and, therefore, the duration of the VF. The duration of the VF is calculated as a function of the value (s) of the quality marker (s). The quality marker (s) may comprise any one or more of the median slope of the ECG, the average slope of the ECG, the ratio of the power in relatively high and low frequency bands of the ECG, and a measure of the density and amplitude of peaks in the ECG, over a predetermined period.

Abstract: An external defibrillator includes patient electrodes (20) for obtaining the patient's electrocardiogram (ECG) and for applying a shock to the patient. A microprocessor (24) analyses the patient's ECU using a diagnostic algorithm to detect if the patient's heart is in a shockable rhythm, and shock delivery circuitry (10) is enabled when a shockable rhythm is detected by the diagnostic algorithm. The patient electrodes also allow obtaining a signal (Z) which is a measure of the patient's transthoracic impedance and the microprocessor is responsive to Z to detect conditions likely to cause the diagnostic algorithm to generate a false detection of a shockable rhythm. If such detection is made, the microprocessor prevents detection of a shockable rhythm by the diagnostic algorithm, at least for a period of time.

Abstract: An apparatus for indicating cardiac output comprises means for monitoring a patient's transthoracic impedance and generating a corresponding impedance signal, and signal processing means for (a) deriving a signal S1 which is a measure of the average amplitude of the impedance signal, (b) filtering the impedance signal at a plurality of different wavelengths within a predetermined frequency band, (c) for each filter deriving a signal S2 which is a measure of the average amplitude of the respective filter output, (d) calculating the ratio of the maximum one of the signals S2 derived from step (c) to the signal S1 derived from step (a), and (e) using the ratio from step (d) in a decision tree to provide a signal indicating cardiac output or not.

Abstract: A method of determining information concerning the identity of an individual comprising measuring at least one biometric of the individual comprising at least one bio-potential waveform generated by the individual's heart, extracting a plurality of characteristics from the bio-potential waveform comprising any of an approximate location of a point of a P peak, an approximate location of a Q-point of a QRS peak system, an approximate location of an R-point of a QRS peak system, an approximate location of an S-point of a QRS peak system, an approximate location of a point of a T peak, using the characteristics to calculate at least one waveform parameter, comparing at least one calculated waveform parameter with at least one previously-acquired waveform parameter to generate a score, and using the score to determine information concerning the identity of the individual.

Abstract: A flexible biomedical surface electrode comprises an insulating substrate (10), a conductive electrode layer (12) screen-printed on the substrate, and an insulating masking layer (14) on the electrode layer. The masking layer is configured to expose selected regions (16) of the electrode layer. An electrically conductive adhesive gel layer (18) on the masking layer makes electrical contact with the exposed regions of the electrode layer.

Abstract: An external defibrillator includes patient electrodes (20) for obtaining the patient's electrocardiogram (ECG) and for applying a shock to the patient. A microprocessor (24) analyses the patient's ECG using a diagnostic algorithm to detect if the patient's heart is in a shockable rhythm, and shock delivery circuitry (10) is enabled when a shockable rhythm is detected by the diagnostic algorithm. The patient electrodes also allow obtaining a signal (Z) which is a measure of the patient's transthoracic impedance and the microprocessor is responsive to Z to detect conditions likely to cause the diagnostic algorithm to generate a false detection of a shockable rhythm. If such detection is made, the microprocessor prevents detection of a shockable rhythm by the diagnostic algorithm, at least for a period of time.

Abstract: A two-part sensor (1) comprising a first part comprising a sensing device (3) which senses information, a second part comprising a receiving device (5) which receives a measure of the information, and a connector (7) comprising at least one first portion (21) which is magnetic and is attached to one of the sensing device and the receiving device, and at least one second portion (23) which is magnetizable and is attached to an other of the sensing device and the receiving device, wherein the first portion and the second portion are connectable and disconnectable to connect and disconnect the sensing device and the receiving device.

Abstract: An H-bridge switching circuit for an automated external defibrillator comprises an SCR (D8) in one of the high legs of the circuit and a control means (D1-D7) associated with the SCR which is operative to switch the SCR on automatically in response to a voltage change across the SCR corresponding to the switching device in the diagonally opposite leg of the H-bridge turning on. The control means comprises a capacitor (D1) and the voltage on the capacitor changes when the diagonally opposite switching device turns on, the change in capacitor voltage lagging the change in voltage across the SCR and the SCR being turned on when the difference between the capacitor voltage and the voltage across the SCR exceeds a predetermined threshold.

Abstract: An external defibrillator estimates the phase of ventricular defibrillation (VF) by deriving, from an ECG exhibiting VF, at least one quality marker representing the morphology of the ECG and, therefore, the duration of the VF. The duration of the VF is calculated as a function of the value (s) of the quality marker (s). The quality marker (s) may comprise any one or more of the median slope of the ECG, the average slope of the ECG, the ratio of the power in relatively high and low frequency bands of the ECG, and a measure of the density and amplitude of peaks in the ECG, over a predetermined period.

Abstract: An apparatus for indicating cardiac output comprises means for monitoring a patient's transthoracic impedance and generating a corresponding impedance signal, and signal processing means for (a) deriving a signal S1 which is a measure of the average amplitude of the impedance signal, (b) filtering the impedance signal at a plurality of different wavelengths within a predetermined frequency band, (c) for each filter deriving a signal S2 which is a measure of the average amplitude of the respective filter output, (d) calculating the ratio of the maximum one of the signals S2 derived from step (c) to the signal S1 derived from step (a), and (e) using the ratio from step (d) in a decision tree to provide a signal indicating cardiac output or not.

Abstract: The invention provides a chest-based oximeter (1) for measuring oxygen saturation of haemoglobin in blood of the chest of a subject, comprising at least one radiation source (5,7) adapted to emit radiation onto the chest, at least one radiation detector (9) adapted to detect radiation reflected from the chest, and a pressure device (11) adapted to apply pressure to the oximeter to connect the oximeter to the chest.

Abstract: A cardiopulmonary resuscitation (CPR) compression force indicator comprises means (20, 26,? 28, 30) for monitoring a patient's transthoracic impedance while the patient is being given CPR and generating a corresponding impedance signal, means (32, 34, 36) for processing the impedance signal to provide an ongoing measurement of cardiac haeraodynamic output, means (24) for determining if the measurement falls outside pre-set limits, and means (38) for indicating such determination externally to the person giving the CPR.

Abstract: A sealed medical electrode package comprises first and second electrodes each comprising a conductive layer (14) disposed on one major surface of a flexible nonconductive backing sheet (10). The electrodes are disposed with their conductive layers (14) face-to-face and their backing sheets separably sealed together around their peripheral edges so that the backing sheets form a substantially gas-impermeable enclosure containing the conductive layers. In an alternative embodiment (FIG. 6) a respective electrical contact extends through each backing sheet into electrical contact with the respective conductive layer, and a substantially gas-impermeable packaging material encloses the electrodes. The packaging material has a respective aperture exposing each electrical contact, the periphery of each aperture being sealed to the backing sheet around the respective contact.

Abstract: A two-part sensor (1) comprising a first part comprising a sensing device (3) which senses information, a second part comprising a receiving device (5) which receives a measure of the information, and a connector (7) comprising at least one first portion (21) which is magnetic and is attached to one of the sensing device and the receiving device, and at least one second portion (23) which is magnetisable and is attached to an other of the sensing device and the receiving device, wherein the first portion and the second portion are connectable and disconnectable to connect and disconnect the sensing device and the receiving device.