Abstract: A high frequency AC electro-surgery apparatus is equipped with an automatic regulation loop for controlling the output voltage (U.sub.a) rather than the output power. An electrically isolating coupling in the form of an isolation transformer (5) is followed by a voltage converter (6) to provide DC voltage signal (a) proportional to a measure of the high frequency AC output voltage (U.sub.a). The DC voltage signal (a) is supplied to a regulating amplifier (7) to which a reference voltage signal (b) is supplied by a reference voltage source (8), to produce an output signal (c) that is furnished to the control input of an electronically controlled power supply (16). The latter controls the operating voltage (U.sub.b) for the amplifier (2) of the high frequency AC generator in such a manner that the output AC voltage (U.sub.a) at the output terminals (10, 11) corresponds to a desired value set by the reference voltage signal (b).

Abstract: Electrosurgery apparatus includes an r.f. power amplifier with an output to a patient electrode. The amplifier is controlled by the voltage of input signals from a control unit which receives a sample of the voltage and current of the output signal. The voltage and current signals are supplied to A/D converters to provide two digital signals that are used to address a look-up table in an EPROM and provide a digital output representative of impedance. A switch is set by the user to the desired mode/power curve and this provides a digital signal which together with the impedance signal is used to address a second look-up table in an EPROM which contains digital representations of the required output voltage of the amplifier to produce the desired power level. An adder compares the required voltage with a feedback of the actual voltage to produce an error signal that is supplied to the amplifier to control its output.

Abstract: An RF surgical apparatus has an RF power stage, a control circuit for driving the power stage, and an adjustable element for setting a rated value of the output power. To monitor the RF surgical apparatus for the occurrence of an apparatus-caused malfunction, a power measuring unit measures the actual value of the RF power at the output of the RF power stage. Deviations of the actual value from a rated value are monitored. An alarm is generated if the deviation exceeds a selected value. An alarm can be simulated in a test mode by means of an auxiliary circuit.

Abstract: This electronic endoscope apparatus comprises an endoscope provided with an imaging apparatus converting a light information of an object to be imaged to an electric signal and a signal processing apparatus processing the output signal of the imaging apparatus to be a video signal. The signal processing apparatus has an isolating device isolating and transmitting the information from the imaging apparatus from the patient circuit side to the secondary circuit side and a converting device converting the signal from the imaging apparatus to a signal adapted to be transmitted by the isolating device and delivering it to the isolating device.

Abstract: Apparatus for monitoring the resistance of the return part of the patient circuit of either a dual foil or single foil return electrode according to a user's selection is disclosed. The apparatus measures the quality of the contact between the return electrode and the patient. A DC or AC converter provides a substantially DC voltage at its input that varies in relation to the resistance of the return part of the patient circuit at its AC output. Preferably, a constant current fed sinusoidal oscillator with a low pass filter at its DC output provides a substantially DC voltage related to the resistance at its AC input. An analog to digital converter converts the substantially DC voltage to a corresponding binary digital signal that is input to a programmed microprocessor. A manually operable set point switch coupled to the microprocessor is acatuated by the user which actuation establishes a resistance level with the pad (return electrode) in place on the patient.

Abstract: An electrode of at least three elements, useful in particular as a neutral electrode for a high frequency surgical instrument. The electrode elements are placed on a common flexible carrier and are arranged symmetrically and rotationally displaced from each other with respect to an axis of symmetry which extends perpendicular from the carrier. Thus, application of the electrode to a patient with respect to an axis of rotation on the patient is not critical and safe monitoring of proper contact on the patient is ensured.

Abstract: A personal health monitor includes sensors for measuring patient weight, temperature, blood pressure, and ECG waveform. The monitor is coupled to a central unit via modems and includes a computer which is programmed to prompt a patient to take prescribed medication at prescribed times, to use the sensors to measure prescribed health parameters, and to supply answers to selected questions. Medication compliance information, test results, and patient answers are compiled in a composite log which is automatically transmitted to the central unit. The computer is also programmed automatically to disconnect the monitor from an alternating current power source and to rely on internal battery power during certain periods of patient-monitor interaction, such as during use of the ECG module. In this way, danger to the patient and complexity of the ECG module are minimized.

Abstract: A protective device for an EKG monitor for use in surgical electrocautery which employs an electrocautery surgical knife supplied with radio frequency power and an EKG monitoring apparatus having an input and including a scope providing an EKG display. Electrodes are provided for attachment to a surgical patient and are connected to the apparatus by the protective device, which includes a radio frequency detector and disabling apparatus which removes signal from the EKG monitor input in the presence of radio frequency energy.

Abstract: A disposable electrosurgical knife handle and blade is provided with a built-in warning light positioned on the top of the handle in the surgeon's line of vision during surgical procedures in order to warn, instantly, of unwanted surges in the electrical system which could bring about tissue damage. Because of the arrangement, the surgeon may remove immediately the blade or other cutting instrument fitted into the handle from the surgical site.

Abstract: A cardiac pacemaker is provided which has combined defibrillation and electrosurgery protection. The pacemaker includes an implantable housing with a pacing circuit located within the housing and means for attaching a lead to the housing. A protection circuit is located between the pacing circuit and the attaching means. The protection circuit comprises a zener diode and a capacitor connected across the zener diode. The capacitor has a value to provide a relatively low impedance with respect to electrosurgery frequencies and a relatively high impedance with respect to cardiac myopotential frequencies.

Abstract: Described is a safety circuit for a high-frequency surgical instrument for the monopolar cutting and coagulating of biological tissue, where the neutral electrode is high-frequency-grounded through a capacitor. The safety circuit monitors the low-frequency leakage current which flows through the capacitor against the ground potential and interrupts the electric connection between this capacitor and ground potential immediately when the low-frequency leakage current exceeds an adjustable limiting value. Simultaneously, an optical signal and an acoustical signal are activated.

Abstract: Having prospectively ascertained a patient's transthoracic resistance upon application of a low amplitude exploration current via the defibrillator electrodes, the capacitor of the defibrillator is charged sufficiently for delivery of a minimal peak current, e.g., 25 amps, preselected by the operator as appropriate for attaining defibrillation, and the capacitor is discharged to effect the defibrillation.

Abstract: Apparatus for partial detection of voltages or charges on the body of a human or animal and for the removal of such voltages or charges, which comprises at least one element which acts as an amplifier or as an electrically controllable switch and has a working-current circuit and a control-current circuit, the latter having a control connection and a common connection for the control-current circuit and working-current circuit; an electrode acting as a probe which is connected to the control connection; an indicating device which is controlled by the current in the working-current circuit; and a voltage control element which, in the absence of external voltage on the probe, maintains the control connection at a predetermined voltage level.

Abstract: The HF-current generator of an electrosurgical apparatus has one terminal connected to an active electrode and an additional terminal connected to a neutral electrode. The neutral electrode consists of at least two partial electrodes which are individually connected via connecting leads to respective current meters for measuing the partial currents in the respective connecting leads. The output side of the current meters are connected to a logic element that is provided for combining the partial currents and which provides a logic signal that is a function of their combination. A ratio generator is preferably provided as the logic element to develop a logic signal that is a function of the ratio of the partial currents. A comparator for comparing the logic signal with pre-set limit value is associated with the logic element. The output signal of the comparator is used as an alarm signal to actuate an alarm or a protective means for a patient in contact with the neutral electrode.

Abstract: An electrical circuit is connected in series with a lead of an implantable heart pacemaker between the pacemaker and the heart to protect the pacemaker against high voltages and currents produced by defibrillators and other sources. The electrical circuit has a sensing resistor arranged between two normally conducting field effect transistors (FETs) all in electrical series with the pacemaker lead. When the voltage drop across the sensing resistor exceeds a predetermined positive or negative amplitude, a transistor becomes conductive and turns off the normal conduction channels of the FETs. An alternate, electrically conductive high-impedance path is switched in to limit the current flow to the pacemaker until the magnitude of the voltage across the sensing resistor drops to a safe level. The transistor then becomes non-conductive and the FETs become conductive re-establishing the normal low-impedance conduction path and effectively switching the alternate high-impedance path out of the circuit.

Abstract: The medical current limiting circuit is for use with medical electrodes and associated diagnostic and therapeutic apparatus. The device protects the apparatus and patient from current flow. The device has circuitry comprising a pair of external connectors, a pair of n-type field effect transistors connected in cascade, a resistor, a p-type field effect transistor, a capacitor to latch the p-FET in a non-conductive state upon its initial activation and a diode to prevent capacitor discharge to the current source.

Abstract: Isolation circuitry for use with diagnostic ECG devices provides high common mode rejection and low leakage current using optoisolators in conjunction with an isolating operational amplifier. A predetermined pattern of binary input signals selectively energizes, via the optoisolators, a plurality of switches interposed between electrodes positioned on a patient's skin and the isolating operational amplifier. This selection couples a predetermined combination of electrodes to the isolating operational amplifier to provide the desired ECG output. The output from the isolating operational amplifier may be coupled directly to a recording device or coupled to a circuit which processes the ECG signal before the signal is recorded.

Abstract: A monitoring arrangement is disclosed for a high frequency surgery device, having a control electrode applied on a patient's body, which detects the high frequency voltage existing on the body surface during the treatment and introduces the same to a monitor circuit. The monitor circuit includes a voltage comparator which compares the body surface voltage with a reference voltage U.sub.ref and upon exceeding the reference voltage U.sub.ref, closes a relay which switches off the high frequency surgery device. The reference voltage U.sub.ref is determined individually for each patient beforehand and corresponds to the maximum tolerable body surface voltage of the particular patient.

Abstract: A stimulator apparatus for applying a low frequency pulse train, modulating a high frequency pulse train, to a patient includes electrodes for placement on the patient in the area of stimulation. A programmable microprocessor generates the pulse train and an electrode driver, to which the low frequency pulse train is fed, is connected to the electrodes. An electrode monitor is connected to an output of the electrode driver, and the output of the monitor is fed to an interrupt terminal of the microprocessor whereby to detect an unacceptable electrode connection. The apparatus also includes a display console including a display arrangement and a switch group. The electrode driver, in accordance with the invention, provides an adjustable constant current to the electrodes.

Abstract: An electrical stimulator for biological tissue utilizing an output current monitor. A drive circuit supplies a transformer output stage with the secondary winding of the transformer coupled across the electrode adapted to be connected to biological tissue. A current monitor and a reference impedance, being substantially greater than the load impedance, are coupled in series with each other and in parallel with the secondary winding and the electrode. In one embodiment, an additional current monitor is coupled in conjunction with the primary winding of the transformer and a comparator is used to compare currents measured by both current monitors.

Abstract: A vital signal monitoring system for monitoring the vital signs of a patient, particularly prior to and during anesthesiology, during and after operational procedures, includes first sensor unit including a microphone for mounting on the patient's chest for picking up breath and heart sounds with a filter and automatic gain control circuit, second sensor unit including a microphone for positioning beneath the blood pressure cuff for picking up the blood flow sounds with a filter and automatic gain control circuit, both connected into a system of electronic components with selection means for selecting either of these sound systems and transmitting the sounds by way of an audio IR transmitter to a portable audio IR receiver carried by a monitoring physician, including an earphone for monitoring the selected sounds. Each sensor unit also includes a thermnistor for measuring the patient's external temperature.

Abstract: A dual element electrical connector for body contact has a flexible base with first and second electrodes secured thereto. A cover secured to the base has an aperture which exposes the electrodes. A sponge pad overlies the electrodes and is impregnated with a conductive gel. The cover is secured to the patient, compressing the sponge pad against him for good body contact. A cable and connection circuit couple the first and second electrodes to an electrical treatment apparatus having two terminals each providing or receiving a similar voltage (or ground) to or from the first and second electrodes. The cable and connection circuit are so constructed that if the treatment apparatus is provided with a device to sense the conductivity between the two terminals and the cable becomes disconnected from either the treatment apparatus or the dual element electrical connector, that condition can be detected.

Abstract: Disclosed is a preamplifier which is responsive to a physiological potential developed by a subject and operative to develop a potential suitably isolated therefrom, the preamplifier including a pair of input networks for receiving therebetween the physiological potential, a pair of operational amplifiers each connected in a unity (voltage) gain, voltage follower, configuration and each driven by a respective one of the input networks, a low resistance resistor connected between the voltage followers to directly develop from the potential a current of suitable level for directly driving an optical isolator, and an optical isolator having an input portion which is connected in the feedback path of one of the operational amplifiers so as to be driven by the current and an output portion at which the optical isolator develops the isolated potential.

Abstract: Vestibular stimulation of a patient is effected by applying to the mastoid area metal, disk-like electrodes covered with insulating material, connected in a series resonant circuit including the electrodes and the body tissues therebetween, energizing the series resonant circuit by an ultrasonic frequency carrier, the frequency of which is determined by the series resonant circuit, and modulating the amplitude of the carrier at a frequency in the range from about 0.1 Hz to about 15 Hz to evoke a nystagmus response. The response is recorded as an indication of the condition of the vestibular system of the patient.

Abstract: An electrosurgical device having a generator for producing a radio frequency current. The device senses an RF current leakage and thereby reduces the output of the RF generator so as to limit the amount of RF leakage to levels below a predetermined value.

Abstract: A control device for a high frequency surgical apparatus having circuitry for sensing excessive heat build-up in body tissue is disclosed. The control device comprises a control electrode, squaring circuit, integrating circuit, comparator and a relay, whereby high frequency current is cut off when the body tissue heat build-up becomes excessive.

Abstract: An electrostatic system monitor and method for monitoring the operation of static control equipment such as conductive workbench and floor mats, conductive wrist straps, and the integrity of ground connections and soldering irons and to activate indicators and alarms when the static control equipment deteriorates or malfunctions by having resistances outside of predetermined values and ranges of resistance. The electrostatic system monitor also provides for the detection of unsafe voltage potentials on soldering irons, and for a surface resistance probe for measuring the surface conductivity of conductive surfaces of the static control equipment.

Abstract: A circuit arrangement adapted for checking the position of electrodes on an object includes a treatment generator for periodically supplying treatment energy and a test impulse independent of the treatment energy to the electrodes. A transfer impedance of a certain magnitude exists between the electrodes; a voltage is developed across, and a current flows through the transfer impedance as a result of the test impulse. An evaluator evaluates the magnitude of the transfer impedance, and includes a test circuit connected to the electrodes for accepting the voltage and/or the current developed across, and flowing through the transfer impedance, respectively, and a warning signal emits a warning signal upon the magnitude of the transfer impedance exceeding or dropping below respective predetermined limit values.

Abstract: An electrolysis machine which utilizes an electrically conductive probe to be physically inserted below the surface of the skin to be located next to a hair shaft within the hair follicle. The electrolysis machine includes two completely separate circuits. One circuit uses a direct current, while the other circuit emits a radio frequency. The amperage of the direct current is controlled to not exceed a certain pre-established value. Upon initial establishment of the circuit with the patient, or re-establishing of the circuit with the patient, surges in electrical current are prevented through the use of a circuit which slows the rise of current to the patient.

Abstract: A circuit for detecting and indicating an interruption in the electrical connection between a signal device and a signal processing device, which has been provided with an amplifier at its input. The signal device has a relatively low impedance and the signal processing device has a relatively high impedance. The circuit includes an alarm device which generates an alarm when the predetermined upper limit of the amplifier input voltage has been exceeded. Also included are a supply circuit to feed an auxiliary dc current into the connection between the signal device and the signal processing device. The supplied auxiliary current is controlled by the amplifier input voltage to rise during an increased amplifier input voltage. As a result, a lower current supply can be provided under normal circumstances, which reduces misinterpretations. Preferably, the circuit is used in connection with ECG measuring devices.

Abstract: Epilator apparatus for outputting epilator pulses comprising a radio frequency generator for generating RF energy. A maximum intensity monitor circuit is coupled to the RF generator and a maximum timing monitor circuit is coupled to the RF generator to predetermine the maximum duration of RF energy output. A power supply including an overvoltage control responsive to the maximum timing monitor circuit and responsive to the maximum intensity monitor circuit for cutting off power including the RF energy when a voltage is reached in excess of a pre-set value.

Abstract: This invention concerns a regulated-current source and a controlled-voltage generator comprising an injector (Ir) kept at a constant potential (U.sub.1) by a regulation loop (D.sub.1, C.sub.1) which by means of a unit (C.G.) controls the intensity (i) of the current flowing in a load (R).

Abstract: An electrosurgery safety monitor senses a parameter indicative of the area of contact between the return electrode of an electrosurgery system and the body of the patient. An alarm is provided if the area of contact between the return electrode and the body is less than a predetermined amount.

Abstract: A system for coupling a plurality of physiological signals across an isolation barrier. A plurality of physiological signals received at a number of signal inputs on the isolated side of the barrier are sampled during separate time periods and coupled to the primary winding of a transformer. The direction of signal flow through the primary winding is reversed during each said period. A pair of serial pulses of opposed polarities are induced in the secondary winding for each sampled signal. The pairs of serial pulses induced in the secondary winding are reconverted to the plurality of physiological signals on the non-isolated side of the barrier.

Abstract: An electrical inhibitor system is disclosed for suppressing the application of transcutaneous nerve stimulator (TNS) signals during the T-wave portion of a heartbeat. The system includes a sensing circuit which is coupled to detect the R-S waveform produced by the heart during its normal beating pattern. Upon detection of the R-S portion of the waveform, an electrical signal is produced and coupled to timing circuitry to produce a timing signal having a duration in excess of the normal period of the T-wave portion of the heartbeat. The timing signal is to inhibit the output of a transcutaneous nerve stimulator during the T-wave portion of the heartbeat. When the inhibiting circuit and transcutaneous nerve stimulator are coupled to a patient, the system provides an inhibiting signal beginning during the R-S portion of the waveform and extending through the T-wave portion of the hearbeat to prevent application of the output from the transcutaneous nerve stimulator during the vulnerable period of the heart.

Abstract: The invention relates to an apparatus for combining pacing and cardioverting functions in a single implanted device, circuitry being provided not only to interface the defibrillator to the ECG amplifier and other elements of the device, but also to provide protection of the ECG amplifier from the defibrillator output pulses, from loading by the defibrillator itself, and from overloading by externally generated defibrillator pulses. A specific embodiment of the invention combines a defibrillator, a pacer and an ECG amplifier in a single implanted device utilizing two terminal-electrode lead combinations for connection to the patient, while further embodiments employ three and four terminal-electrode lead combinations. The invention employs a high-frequency transformer coupling technique for pacing, or, alternatively, high-frequency transformer coupling with modulation-demodulation.

Abstract: Leakage cancelling apparatus suitable for use in electrosurgery apparatus to prevent electrical burns is disclosed. The apparatus comprises a transformer which is connected in the electrical circuit between the electrosurgical source and the patient. The transformer has a primary winding connected in series with the active surgical electrode and a secondary winding connected in series with the return path to the electrosurgical generator. The connections to the windings are polarized so that during normal operation the magnetic fields in the transformer core generated by current flow are almost completely cancelled. Consequently, the transformer windings present very small impedances in series with the electrosurgical circuit.

Abstract: A return electrode monitoring system for use with a split patient return electrode having two, electrically isolated electrode elements adapted for contacting a patient, the system comprising means responsive to the impedance between the two electrode elements for producing a signal which is a function of the impedance; means for establishing a desired range having an upper limit and a lower limit for the impedance when the patient is in contact with the electrode elements; determining means responsive to the signal for determining whether the impedance is within the desired range; and adjusting means for adjusting the upper limit to adapt the system to the particular impedance of the patient in response to the particular impedance occurring within the desired range.

Abstract: In the case of current stimulation apparatus, in particular, protection installations are necessary which, in every instance, disconnect the patient from the operating voltage of the apparatus when maximally permissible patient currents are exceeded. For this purpose, for example, safety fuses or also electromagnetic disconnection devices (relays) are known. In accordance with the disclosure, a safety circuit for disconnecting the patient output from the operating voltage is employed as the protection installation which also responds when the patient current deviates from a preselected desired value adjusted on an intensity adjustment member. For this purpose, an output stage as current waveform generator for constant-current stimulation current is connected with the safety circuit.

Abstract: Current stimulation apparatus, in particular, exhibits an output stage as the current waveform generator for producing an output current through a patient's body as the load resistance. Such apparatus operates with a specifiable operating voltage and controls the patient current in a constant-current fashion in the case of a varying load resistance. Preferably, the patient current is here measured through determination of the voltage across defined resistance terminals, whereby magnitude as well as peak values can be displayed on the display units associated with the output stage. Up to the present time, the measuring and display units had been fed by power supply units which deliver a supply voltage in relation to operating potential. According to the disclosure, all units for measuring, further processing, and/or display of the patient current are decoupled from the operating voltage circuit and receive supply voltages which are directly defined in relation to ground potential.

Abstract: A pair of toroidally wound cores are maintained in a generally parallel, vertical, spaced apart relationship by a tubular insulating member passing through the toroid centers. The tubular member insulates the windings from a coupling loop which passes through the tube and which closes outside the toroidal windings. One winding is the primary of the isolation circuit, connecting the source of signals through a FET device to ground, and the other winding is secondary winding, which is also connected to ground through a FET, and which is coupled to a utilization device through a low pass filter. The FET devices are synchronously pulsed at a frequency above the signal frequency and the filter pass band.

Abstract: A current-limiter device is placed in series circuit between a pacemaker and the proximal end of an electrode to prevent tissue damage adjacent the distal end of the electrode which otherwise may have occurred during defibrillation, cardioversion, or diathermy.

Abstract: An electrical surgical knife which may be inserted into a body cavity of a patient through an endoscope in which electrical shock to the patient or user of the knife is prevented. A positive polarity electrode of the knife is disposed inside a flexible insulating tube. Around all but an end protruding active portion of the positive polarity electrode there is disposed a conductive metal sheath which is insulated therefrom. The metal sheath is electrically connected to a metal plate electrode which is adapted to be disposed in electrical contact with the skin of a patient.

Abstract: An electrosurgery safety monitor senses a parameter indicative of the area of contact between the return electrode of an electrosurgery system and the body of the patient. An alarm is provided if the area of contact between the return electrode and the body is less than a predetermined amount.

Abstract: An electrosurge generator, which is energized by a power supply to produce n output voltage of a desired level, includes a failsafe system at its output to prevent any excessive high DC voltage output which may result from a failure in the electrosurge generator. The failsafe system has a detection element coupled to the output of the electrosurge generator which detects any output above a predetermined threshold. A switching circuit is activated by the detection element. The switching circuit is connected across the power supply, and when activated, removes the power supplied from the power supply to the electrosurge generator.

Abstract: An apparatus for use in a system for transmitting information in the form of electric stimuli to a subject through the medium of a multiplicity of electrodes attached to the subject, which apparatus comprises analogue switches provided one each for the electrodes at their respective input sides and a decoder adapted to effect the "ON-OFF" control of these analogue switches. The pulse signals generated by a stimulator to represent a given piece of information are transmitted to the analogue switches, and then the pulse signals are applied to the subject only through the electrodes which are in their "ON" state at the time of the reception of the signals, giving required electric stimuli to the subject.

Abstract: In an exemplary embodiment a multiplexer unit is arranged in the first device unit in the input channels for electric physiological signals and a demultiplexer unit is arranged in the second device unit on the side of the output channels for the time-shared scanning of the signals in the input or, respectively, output channel; and a pulse amplitude modulator and a single galvanically separating coupling location are inserted in series between the multiplexer unit of the first device unit and the demultiplexer unit of the second device unit at the interface between both device units for the de-coupled signal transmission in the time multiplex mode. By this arrangement the minimized number of coupling locations holds coupling capacitance and leakage current to a minimum with only a modest outlay for appertaining control circuitry.

Abstract: In signal measurement circuits which are referred to a floating ground and which derive their input signals from electrodes attached to a patient's body, the effects of common mode potentials on the patient's body are minimized without requiring any patient electrodes other than those acting as signal sources, by using an operational amplifier to drive the floating ground toward the common mode potential on the patient's body.This process is accomplished without significantly degrading the isolation impedance between the measurement circuits and true ground.The patient is protected from hazardous electrical shock by incorporating a current limiting impedance in the amplifier circuit.

Abstract: In signal measurement circuits which are referred to a floating ground and which derive their input signals from electrodes attached to a patient's body, the effects of common mode potentials on the patient's body are minimized without requiring any patient electrodes other than those acting as signal sources by using a unity gain amplifier to drive the floating ground toward the common mode potential on the patient's body.This process is accomplished without significantly degrading the isolation impedance between the measurement circuits and true ground.The patient is protected from hazardous electrical shock by referencing the unity gain amplifier to a given point and connecting a large impedance between that point and true ground.

Abstract: In a surgical system for high frequency electrical cutting and cauterizing circuitry to prevent stray currents from harming the surgeon or the patient. This circuitry provides a preferred path for undesirable currents, and to indicate to a surgeon when the undesirable currents are too intense.