Abstract: An electrotherapy delivery device includes an upper member having a handle portion and a pediatric electrode mounted to the bottom surface of the upper member. A base member having an adult electrode is selectively attached to the upper member with a coupling mechanism to conceal the pediatric electrode. The upper member attaches to the base member across diametrically opposed corners of the base member to provide the user with a more ergonomic hand position when accessing the paddles from the defibrillator. The device further include a plurality of switches operable to deliver a charge and to select the level of charge to be delivered to the patient. The paddle is provided with a processing circuit that receives an output from separate energy level increase and decrease switches, processes the output from the switches, and outputs a signal to the defibrillator corresponding to the level of energy selected by the switches.

Abstract: An external defibrillator having an output circuit that allows a defibrillation pulse to be discharged to a patient is provided. The output circuit, charging circuit, preamplifier circuit, impedance measurement circuit, energy storage device, battery, and measurement and control circuits of the defibrillator are all referenced to a common ground. The use of a common ground is simpler and less expensive than previous designs which utilized isolation stages and circuits for isolating the high and low voltage circuitry. The output circuit is in the form of an H-bridge which contains three SCR legs and one IGBT leg. Each of the legs contains a single semiconductor switch. The IGBT is placed in the northwest leg of the H-bridge. The two lower legs each contain SCRs, one or both of which may be driven by DC gate drive signals.

Abstract: A pulse detection apparatus, software, and method that uses signal data obtained from an accelerometer placed on a patient's body to detect the presence of a cardiac pulse. The accelerometer is adapted to sense movement due to a cardiac pulse and produce accelerometer signal data in response thereto. Processing circuitry analyzes the accelerometer signal data for a feature indicative of a cardiac pulse and determines whether a cardiac pulse is present in the patient based on the feature. In one aspect, the feature may be a temporal energy feature, such as a relative change in energy. In another aspect, the feature may be a spectral energy feature such as the energy or frequency of a peak in the energy spectrum of the signal. In yet another aspect, the feature may be obtained by comparing the accelerometer signal data with a previously-identified pattern known to predict the presence of a cardiac pulse. Multiple features may also be obtained and classified to determine the presence of a cardiac pulse.

Abstract: A circuit for generating both a biphasic defibrillation waveform and an external pacing waveform in an external defibrillator is provided. The output circuit of the device utilizes one or more SCR switches for applying energy to a patient. In one embodiment, the output circuit is in the form of an H-bridge, with three SCR legs and one IGBT leg. A drive circuit for one of the SCR legs is provided such that the SCR may be continuously driven on for either a high energy biphasic defibrillation pulse or a low energy pacing pulse. In one embodiment, the output circuit conducts the pacing waveform through a combination of one upper leg SCR of the H-bridge and a current source. The current source is configured to bypass a lower leg SCR of the H-bridge. The output circuit is capable of conducting pacing currents of as low as 10 mA.

Abstract: The present invention provides a therapy-delivering, portable medical device (200) capable of triggering and/or communicating with an alarm system (100), as well as a related system and method therefor. The portable medical device (200) is configured to establish a communication link (107) with an alarm system (100) such as a residential or business alarm, upon the occurrence of a triggering event. Triggering events may be related to the use, operation or deployment of the portable medical device (200) in an emergency situation, or they may be for service, status or maintenance purposes, e.g., to report device failures, system checks, etc. The portable medical device (200) is configured to deliver therapy to a patient, wherein the therapy delivered to the patient may be any or combination of medial therapies, e.g., defibrillation, drugs, etc., for any one or combination of medical applications, such as stroke, cardiac arrest, diabetic shock, etc.

Abstract: The invention provides a method for sequentially activating a medical device and exposing at least a portion of the user interface of the medical device to an operator, in a single action to be performed by the operator. The medical device, for example, an automated external defibrillator (AED), includes a housing having a user interface and a lid that is coupled to the housing. The lid, when closed, is covering at least a portion of the user interface. In one embodiment, the medical device further includes an on/off button. The button is configured such that, when an operator depresses the button, it causes a switch to close to thereby activate the medical device, and further causes the lid to open via a latch mechanism.

Abstract: A selectively removable charging pack is provided, which is operable to recharge the power source of a portable external defibrillator when coupled thereto. The charging pack comprises an elongate body of generally triangular shaped cross-section having a front region, a back region, a top region, and left and right sides and that form a bottom region at the convergence of left and right sides. The body houses a charging source in the form of charging cells that are operable to recharge the power source of a portable external defibrillator when inserted in its charging well. The front of the charging pack is formed with a latch, which may be utilized by a user to remove the charging pack from the defibrillator. The latch automatically secures the charging pack in the charging well when the charging pack is inserted into the defibrillator.

Abstract: A method and apparatus for performing self-tests on defibrillation and pacing circuits including a patient isolation switch is disclosed. Tests are provided for the defibrillation and pacing circuitry as well as the isolation switch. For testing the defibrillation circuitry, the impedance drive circuits and preamplifier may be utilized such that the energy storage capacitor is not required to be charged and discharged during the test, thus conserving energy. For testing the pacing circuitry and the isolation switch, the defibrillation circuitry is utilized. For certain of the tests, the test stimulus is the output voltage on the energy storage capacitor, while for other tests the test stimulus may be the pace current as indicated by the voltage across the input to the preamplifier. Alternative tests may be performed depending on whether the impedance at the output of the defibrillator is determined to be an open circuit or a short circuit.

Abstract: Medical electrode arrangements are provided for electrotherapy and monitoring applications. In one embodiment, each electrode arrangement includes a smaller electrode that is releasably attached to the back of a larger electrode. For adult applications, the larger electrode is applied to the patient. For pediatric applications, the larger electrode is preferably removed, and the smaller electrode is applied to the patient. Face-to-face and back-to-back electrode arrangement configurations are also provided. In another embodiment, an electrode arrangement is comprised of first and second conductive regions that are separable from each other. In yet further embodiments, an electrode arrangement is comprised of two or more electrodes that are not physically or electrically connected to each other. At least one electrode from each electrode arrangement is placed on the patient. A sensor is also provided to sense which electrodes in each electrode arrangement have been placed on the patient.

Abstract: A method and apparatus for performing self-tests on defibrillation and pacing circuits including a patient isolation switch is disclosed. Following a test of the defibrillation and pacing circuitry, the isolation switch is tested by closing certain switches within the defibrillation circuitry so as to create a circuit path, and then opening and closing the isolation switch. Alternative tests may be performed depending on whether the impedance at the output of the defibrillator is determined to be an open circuit or a short circuit. If the output is determined to be an open circuit, then the test monitors the voltage across the output of the defibrillator as indicated by the voltage of a DC offset of a preamplifier coupled to the output of the defibrillator. For the short circuit test, the voltage on the energy storage capacitor is monitored.

Abstract: A system is described that comprises a medical device on which is installed a version of software and a software agent communicatively coupled to the medical device without regard to the version of software installed on the medical device. An example of the medical device includes a defibrillator. The software agent may reside in a personal digital assistant and can be operated to communicate with the defibrillator to access the data stored in the defibrillator irrespective of the version of software of the defibrillator.

Abstract: The presence of a cardiac pulse in a patient is determined by evaluating fluctuations in an electrical signal that represents a measurement of the patient's transthoracic impedance. Impedance signal data obtained from the patient is analyzed for a feature indicative of the presence of a cardiac pulse. Whether a cardiac pulse is present in the patient is determined based on the feature in the impedance signal data. Electrocardiogram (ECG) data may also be obtained in time coordination with the impedance signal data. Various applications for the pulse detection of the invention include detection of PEA and prompting PEA-specific therapy, prompting defibrillation therapy and/or CPR, and prompting rescue breathing depending on detection of respiration.

Abstract: The present invention provides a system, method and apparatus for obtaining status information from a portable medical device and communicating said status information to a remote system or user. In one embodiment, the system comprises a sensing device that comprises an optical receiver for receiving status information from at least one status indicator of the portable medical device. The optical receiver is positioned in sufficient proximity to the status indicator to allow optical communication between the optical receiver and the status indicator. A circuit couplable to the optical receiver communicates the status information represented by the status indicator to the remote system or user. In another embodiment, the sensing device comprises a microphone to receive audible status signals from the portable medical device. In yet another embodiment, the sensing device is mounted to a housing, which allows sensing device to sense the status information of an enclosed portable medical device.

Abstract: The presence of a cardiac pulse in a patient is determined by evaluating physiological signals in the patient. In one embodiment, a medical device evaluates two or more different physiological signals, such as phonocardiogram (PCG) signals, electrocardiogram (ECG) signals, patient impedance signals, piezoelectric signals, and accelerometer signals for features indicative of the presence of a cardiac pulse. Using these features, the medical device determines whether a cardiac pulse is present in the patient. The medical device may also be configured to report whether the patient is in a VF, VT, asystole, or PEA condition, in addition to being in a pulseless condition, and prompt different therapies, such as chest compressions, rescue breathing, defibrillation, and PEA-specific electrotherapy, depending on the analysis of the physiological signals. Auto-capture of a cardiac pulse using pacing stimuli is further provided.

Abstract: An energy adjusting circuit for use with a defibrillator. The energy adjusting circuit reduces the defibrillation pulse energy that would otherwise be applied to the patient by the defibrillator. The energy adjusting circuit can be part of the defibrillator itself, or part of an adapter coupled to the output ports of a conventional defibrillator. In an adapter designed for pediatric defibrillation, the adapter may include paddles configured for use on babies and small children. The energy adjusting circuit may be formed entirely from passive components and may include a divider circuit with two resistors. The resistance of the two resistors is selected so as to absorb a predetermined percentage of the defibrillation pulse energy that would otherwise be applied to the patient. An isolation circuit may be further included to assist with the measurement of ECG signals through the electrodes.

Abstract: The invention provides a wireless automatic location identification (ALI) capable system (10), including a medical device (12) having a wireless data communicator (14), a wireless communication network (16), and a remote locating service (18) for remotely locating and monitoring one or more medical devices over the wireless communication network. When the medical device is linked to the remote locating service over the communication network, the ALI-capable system identifies the location of the medical device and relays the location information to the remote locating service. The system permits reliable determination of the location of the medical device wherever the medical device is situated. The medical device may further be configured to transmit signals indicative of its status, condition, or self-test results, to the remote locating service. This feature allows the remote locating service to centrally monitor the status or condition of a plurality of medical devices.

Abstract: A medical device constructed according to the invention includes electrodes (12a, 12b), a measuring unit (24) for measuring a patient-dependent electrical parameter (e.g., impedance) of the patient, an electrotherapy generator (26) for delivering electrotherapy to the patient, and a processing unit (20) for controlling the delivery of electrotherapy to the patient. Electrotherapy is preferably delivered to the patient based on the measured patient-dependent electrical parameter and a predetermined response of a reference patient to a nominal electrotherapy. The actual electrotherapy delivered to the patient is controlled so that the electrotherapy has a probability of success for the patient that is equivalent to the probability of success of the nominal electrotherapy for the reference patient. A consistent shock efficacy across different patients is achieved.

Abstract: An external defibrillator with an output circuit having four legs arrayed in the form of an “H” (an “H-bridge”) is disclosed. The output circuit is designed to be able to conduct a range of defibrillation pulse energies, from below 50 joules to above 200 joules. Each leg of the output circuit contains a solid-state switch. By selectively switching on pairs of switches in the H-bridge, a biphasic defibrillation pulse may be applied to a patient. The switches in three of the legs of the H-bridge output circuit are preferably silicon controlled rectifiers (SCRs). Gate drive circuits are coupled to the SCRs to bias the SCRs with a voltage that allows the SCRs to remain turned-on even when conducting low current. The switch in the fourth leg is preferably a pair of insulated gate bipolar transistors (IGBTs) coupled in series. A gate drive circuit is coupled to the gate of the IGBTs to provide a slow turn-on and a fast turn-off of the IGBTs.

Abstract: A method and apparatus determines the presence of a cardiac pulse in a patient by evaluating a physiological signal in the patient, preferably for the presence of characteristic heart sounds. The presence of a heart sound in a patient is determined by analyzing phonocardiogram (PCG) data obtained from the patient. Analyzing the PCG data may include evaluating temporal energy in the PCG data or evaluating spectral energy in the PCG data. Evaluating temporal energy in the PCG data may include estimating a first and second energy in the PCG data and comparing the first and second energy to determine a relative change in energy between them. Evaluating spectral energy in the PCG data may include calculating an energy spectrum of the PCG data and evaluating either the energy value or the frequency of a peak energy in the energy spectrum. The presence of a heart sound may also be determined by combining an evaluation of temporal energy with an evaluation of spectral energy in the PCG data.