WO1999019020A1 - Magnetically compatible peripheral nerve stimulator - Google Patents

Magnetically compatible peripheral nerve stimulator Download PDF

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Publication number
WO1999019020A1
WO1999019020A1 PCT/US1998/021834 US9821834W WO9919020A1 WO 1999019020 A1 WO1999019020 A1 WO 1999019020A1 US 9821834 W US9821834 W US 9821834W WO 9919020 A1 WO9919020 A1 WO 9919020A1
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WO
WIPO (PCT)
Prior art keywords
signal
voltage
mode
living tissue
electrical signal
Prior art date
Application number
PCT/US1998/021834
Other languages
French (fr)
Inventor
Andrew J. Soltyk
Jimmie B. Allred, Iii
Earl R. Holdren, Iii
Original Assignee
Minrad Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minrad Inc. filed Critical Minrad Inc.
Priority to AU10916/99A priority Critical patent/AU1091699A/en
Publication of WO1999019020A1 publication Critical patent/WO1999019020A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/025—Digital circuitry features of electrotherapy devices, e.g. memory, clocks, processors
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372—Arrangements in connection with the implantation of stimulators
    • A61N1/375—Constructional arrangements, e.g. casings
    • A61N1/3756—Casings with electrodes thereon, e.g. leadless stimulators
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves 
    • A61B5/055—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
    • A61B5/1104—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb induced by stimuli or drugs
    • A61B5/1106—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb induced by stimuli or drugs to assess neuromuscular blockade, e.g. to estimate depth of anaesthesia
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/36014—External stimulators, e.g. with patch electrodes
    • A61N1/3603—Control systems
    • A61N1/36034—Control systems specified by the stimulation parameters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362—Heart stimulators
    • A61N1/37—Monitoring; Protecting
    • A61N1/3718—Monitoring of or protection against external electromagnetic fields or currents
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372—Arrangements in connection with the implantation of stimulators
    • A61N1/378—Electrical supply

Definitions

  • This invention relates to externally applying an electrical pulse to the central nervous system, and more particularly to a new and improved peripheral nerve stimulator.
  • Peripheral nerve stimulators are used for monitoring depth of anesthetic during a surgical procedure performed on a patient.
  • the current state of technology of the peripheral nerve stimulator is mature and well understood.
  • a step-up transformer amplifies the signal in the conventional peripheral nerve stimulator.
  • the transformer core makes the instrument sufficiently magnetic to be unsafe for use in the intense magnetic field of an MRI (Magnetic Resonance Imaging) unit.
  • MRI Magnetic Resonance Imaging
  • This is becoming an issue with the advent of interventional MRI, where surgical procedures are performed under real time MRI, and the patient is operated upon in the magnetic field of the MRI unit.
  • the magnetic forces applied to the magnetically susceptible nerve stimulator could interfere with the actions of personnel in the MRI suite.
  • the present invention solves this problem by providing a magnetically compatible peripheral nerve stimulator for providing pain control during a surgical procedure performed on a patient while inside an MRI suite .
  • the present invention provides a peripheral nerve stimulator of low magnetic susceptibility that can be used in the high magnetic field of an MRI suite.
  • Non-magnetic lithium batteries power the peripheral nerve stimulator.
  • a stack of capacitors and diodes (hereinafter "components") forming a voltage multiplier replace the conventional step-up transformer. Each Component is carefully chosen for low content of the magnetic materials. To minimize the number of components
  • a full H-bridge supplies power to the multiplier.
  • the power is an AC signal with voltage equal or plus or minus to the supply voltage. This provides a peak to peak voltage value of two times the available battery voltage.
  • This approach reduces the number of capacitors and diodes to half, compared to the half bridge solution.
  • miniature surface mount Shotky Diodes are used.
  • a high switching frequency (1MHz) mode of operation is employed.
  • Fig. 1 is a schematic circuit diagram of the magnetically compatible peripheral nerve stimulator according to the present invention.
  • Fig. 2 is a schematic circuit diagram of another embodiment of the voltage multiplier in the circuit of Fig. 1 ;
  • Figs . 3A and 3B are graphs including waveforms illustrating operation of the voltage multiplier of Fig. 2;
  • Figs . 4A - 4D are graphs including waveforms illustrating various modes of operation of the stimulator of Fig. 1 ;
  • Fig. 5 is a graph including waveforms further illustrating operation of the stimulator of Fig. 1;
  • Fig. 6 is an elevational view of the magnetically compatible peripheral nerve stimulator apparatus according to the prevent invention.
  • the present invention provides a magnetic resonance imaging (MRI) compatible peripheral nerve stimulator.
  • the stimulator is used for pain control during a surgical procedure performed on a patient while inside an MRI apparatus.
  • the MRI compatible nerve stimulator substitutes the conventional step-up transformer with a diode-capacitor voltage multiplier array. Thereby, the device reduces its magnetic susceptibility.
  • the trigger circuit for the device includes common 555 timers. Further refinements include the use of a full H-bridge power supply, a 1 Mhz switching frequency to the diode-capacitor voltage multiplier, the use of the surface-mount Shotky diodes, and a lithium battery pack. These refinements reduce the number of components, overall size, and further reduce the magnetic susceptibility of the nerve stimulator.
  • Fig. 1 which is a schematic circuit diagram of the magnetically compatible peripheral nerve stimulator 10 of the present invention
  • the diode-capacitor voltage multiplier is shown at 12 and the trigger circuit is designated 14.
  • the stimulator output pulses are provided across terminals 16 and 18.
  • Fig. 2 is a schematic circuit diagram of an alternative form of diode-capacitor voltage multiplier 20 which can be utilized in the circuit of Fig. 1.
  • Figs. 4A-4D show different output pulse trains corresponding to four operational modes of the stimulator of Fig. 1.
  • Pulses 30 in Fig. 4A are a train of four mode and pulses 32 in Fig.
  • Fig. 4B are a tetanus mode.
  • Pulses 34 in Fig. 4C are a twitch mode and pulses 36 in Fig. 4D are a double burst mode. These modes will be described in further detail presently.
  • the curves 40, 42 and 44 in Fig. 5 illustrate output impedance characteristics for the stimulator of Fig. 1 in response to variation in operational parameters.
  • Fig. 6 is an elevational view of the stimulator 10 of Fig. 1 contained in a rectangular housing 50.
  • Output ball electrodes 52 and 54 are connected to terminals 16 and 18, respectively, of the circuit of Fig. 1.
  • the apparatus includes a battery L.E.D. indicator 58 and an output stimulator pulse
  • L.E.D. indicator 60 An on-off switch for the apparatus is designated 62.
  • the four modes of operation are controlled by twitch key 64, train of four key 66, double burst stimulation key 68 and tetanus key 70.
  • the apparatus is intended for monitoring the effects of skeletal muscle relaxants in an MR or interventional MR environment, not to exceed a 1.5 Telsa field strength. It has been tested and shown to be safe and effective for normal use in a 1.5T GE Signa System. The apparatus is not intended to be used in the magnet bore while imaging due to potential distortion of the MR image .
  • the four pulse stimulation modes previously described have the following characteristics.
  • DOUBLE BURST is two groups of three 200uS impulses, pulses every 20mS, and groups separated by 1 second.
  • TWITCH is 200uS pulses every 1 second continuous.
  • TENANUS is 200 uS pulses every 20mS continuous.
  • TRAIN-OF-FOUR is four 200uS pulses every 1/2
  • the yellow pulse LED 60 flashes each time a pulse is generated.
  • the green battery LED 58 indicates that the power is on, and the battery voltage is sufficient.
  • the apparatus is powered by one Greatbatch Scientific Battery Pack No. GN-7B0194. Housing 50 can be high impact ABS plastic, 2.75" x 4.50" x 1.50". The apparatus has a weight of 11.3 oz . , including battery.
  • the stimulator apparatus is controlled by the four push buttons or keys 64, 66, 68 and 70 on the case 50, and by the combination potentiometer control knob and switch 62 also on the case 50.
  • the green LED 58 labeled BATTERY, indicates the power is on, and the battery voltage is sufficient.
  • the yellow LED 60 labeled PULSE, indicates output impulses, and will flash each time an output stimulus pulse is generated.
  • An audio indicator located inside the case 50 gives audio indication of output impulses along with the yellow LED 60.
  • the device is activated by turning the potentiometer control knob 62 until a light click is heard. The maximum counter-clockwise position of the control knob is power off.
  • the Potentiometer adjusts the amplitude of the impulses from zero to 400 Volts.
  • the ball electrodes 52 and 54 are placed in direct contact with the patient.
  • the Double Burst Stimulation (DBS) button 68 delivers two groups of three impulses each.
  • the impulses are 200 microseconds long, spaced 20 milliseconds apart within the group, with the groups spaced 1 second apart.
  • the yellow PULSE LED 60 indicates the impulses being generated. Before the next group of impulses can be generated, the DBS button 68 must be released. Additional sets of pulses can be generated by depressing the DBS button 68.
  • the TWITCH button 64 delivers a continuous waveform of impulses 200 microseconds each, spaced 1 second apart as long as the button is depressed.
  • the yellow PULSE LED 60 indicates the impulses are being generated.
  • the TETANUS button 70 delivers a continuous waveform of impulses 200 microseconds each, spaced 20 milliseconds apart as long as the button is depressed.
  • the yellow PULSE LED 60 indicates the impulses are being generated.
  • the Train-of-Four (TOF) button 66 delivers a train of four impulses 200 microseconds each, spaced 500 milliseconds apart.
  • the yellow PULSE LED 60 indicates the impulses are being generated. Depressing the button will deliver only a single train of four impulses.
  • the TOF button 66 Before the next group of impulses can be generated the TOF button 66 must be released.
  • the series of train-of- four pulses can be repeated as often as one wishes by repeated depressing of the TOF button 66.
  • One use involves the neuromuscular junction.
  • the impulse passing down a motor nerve is transmitted to a muscle across the motor end plate or neuromuscular junction.
  • the transmission of this impulse is medicated via acetylcholine which becomes attached to specific receptors sites on the motor end plate.
  • it is the blockade of transmission across the neuromuscular junction by muscle relaxants that produce muscle relaxations. Although all muscle relaxants act on the neuromuscular junction, the mode and duration of action and intensity of blockade differ for different agents.
  • These specific aspects of the action of neuromuscular agents can be differentiated by nerve stimulation using the magnetically compatible peripheral nerve stimulator of the present invention.
  • Another use relates to depolarizing and non- depolarizing blockade.
  • Physiological conduction across the neuromuscular junction is by depolarization of the motor end plate by acthycholine .
  • This depolarization is of exceedingly short duration.
  • Depolarizing relaxants such as succinylcholine chloride cause depolarization of the end plate but the recovery period is much greater and extends to minutes rather than milliseconds.
  • Prolonged depolarization causes neuromuscular blockade.
  • Non-depolarizing relaxants such as d-tubocurarine chloride do not cause depolarization; rather they occupy the specific receptor sites on the motor end plate. This prevents acetylcholine from attaching to the receptor sites.
  • the duration of action of these drugs is probably dependent on how long they occupy the receptor sites.
  • the difference in the type of blockade produced by the depolarizing or non-depolarizing relaxants accounts for their differing response to nerve stimulation, such as that provided by the magnetically compatible peripheral nerve stimulator of the present
  • the magnetically compatible peripheral nerve stimulator of the present invention can be used in detection of the type of neuromuscular blockade.
  • the response to a brief train of stimuli is a more sensitive index of receptor blockade by a competitive neuromuscular blocking agent than is the response to a single twitch.
  • the Train-of-Four stimulus may produce less discomfort in a conscious patient than a tetanic stimulus.
  • Double Burst Stimulation is a pattern of stimulation developed to reveal residual neuromuscular blockade. DBS was developed with the specific aim of allowing manual (tactile) detection of small amounts of residual neuromuscular blockade under clinical conditions.

Abstract

The present invention provides a peripheral nerve stimulator (10) of low magnetic susceptibility that can be used in the high magnetic field of an MRI suite. Non-magnetic lithium batteries power the peripheral nerve stimulator. A stack of capacitors, and diodes (hereinafter 'components') forming a voltage multiplier (20) replace the conventional step-up transformer. Each component is carefully chosen for low content of the magnetic materials. To minimise the number of components, and enable the magnetically compatible peripheral nerve stimulator to be a handheld instrument, a full H bridge supplies power to the multiplier. The power is an AC signal with voltage equal or plus or minus to the supply voltage. This provides a peak to peak voltage value of two times the available battery voltage. This approach reduces the number of capacitors, and diodes to half compared to the half bridge solution.

Description

MAGNETICALLY COMPATIBLE PERIPHERAL NERVE STIMULATOR
CROSS REFERENCE TO A RELATED APPLICATION
This application claims priority of earlier filed provisional patent application Serial No. 60/063,996, filed on October 15, 1997, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to externally applying an electrical pulse to the central nervous system, and more particularly to a new and improved peripheral nerve stimulator.
2. Background of the Invention
Peripheral nerve stimulators are used for monitoring depth of anesthetic during a surgical procedure performed on a patient. The current state of technology of the peripheral nerve stimulator is mature and well understood. A step-up transformer amplifies the signal in the conventional peripheral nerve stimulator. The transformer core makes the instrument sufficiently magnetic to be unsafe for use in the intense magnetic field of an MRI (Magnetic Resonance Imaging) unit. This is becoming an issue with the advent of interventional MRI, where surgical procedures are performed under real time MRI, and the patient is operated upon in the magnetic field of the MRI unit. The magnetic forces applied to the magnetically susceptible nerve stimulator could interfere with the actions of personnel in the MRI suite. The present invention solves this problem by providing a magnetically compatible peripheral nerve stimulator for providing pain control during a surgical procedure performed on a patient while inside an MRI suite .
SUMMARY OF THE INVENTION
The present invention provides a peripheral nerve stimulator of low magnetic susceptibility that can be used in the high magnetic field of an MRI suite. Non-magnetic lithium batteries power the peripheral nerve stimulator. A stack of capacitors and diodes (hereinafter "components") forming a voltage multiplier replace the conventional step-up transformer. Each Component is carefully chosen for low content of the magnetic materials. To minimize the number of
Components, and enable the magnetically compatible peripheral nerve stimulator to be a hand-held instrument, a full H-bridge supplies power to the multiplier. The power is an AC signal with voltage equal or plus or minus to the supply voltage. This provides a peak to peak voltage value of two times the available battery voltage. This approach reduces the number of capacitors and diodes to half, compared to the half bridge solution. To increase efficiency of the diodes, miniature surface mount Shotky Diodes are used. To reduce the size of the capacitors, a high switching frequency (1MHz) mode of operation is employed.
The following detailed description of the invention, when read in conjunction with the accompanying drawings wherein the same reference numerals denote the same or similar parts throughout the several views, is in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains, or with which it is mostly nearly connected, to make and use the invention. BRIEF DESCRIPTION OF THE DRAWING FIGURES
Fig. 1 is a schematic circuit diagram of the magnetically compatible peripheral nerve stimulator according to the present invention;
Fig. 2 is a schematic circuit diagram of another embodiment of the voltage multiplier in the circuit of Fig. 1 ;
Figs . 3A and 3B are graphs including waveforms illustrating operation of the voltage multiplier of Fig. 2;
Figs . 4A - 4D are graphs including waveforms illustrating various modes of operation of the stimulator of Fig. 1 ; Fig. 5 is a graph including waveforms further illustrating operation of the stimulator of Fig. 1; and
Fig. 6 is an elevational view of the magnetically compatible peripheral nerve stimulator apparatus according to the prevent invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a magnetic resonance imaging (MRI) compatible peripheral nerve stimulator. The stimulator is used for pain control during a surgical procedure performed on a patient while inside an MRI apparatus. The MRI compatible nerve stimulator substitutes the conventional step-up transformer with a diode-capacitor voltage multiplier array. Thereby, the device reduces its magnetic susceptibility. The trigger circuit for the device includes common 555 timers. Further refinements include the use of a full H-bridge power supply, a 1 Mhz switching frequency to the diode-capacitor voltage multiplier, the use of the surface-mount Shotky diodes, and a lithium battery pack. These refinements reduce the number of components, overall size, and further reduce the magnetic susceptibility of the nerve stimulator.
Referring to Fig. 1 which is a schematic circuit diagram of the magnetically compatible peripheral nerve stimulator 10 of the present invention, the diode-capacitor voltage multiplier is shown at 12 and the trigger circuit is designated 14. The stimulator output pulses are provided across terminals 16 and 18. Fig. 2 is a schematic circuit diagram of an alternative form of diode-capacitor voltage multiplier 20 which can be utilized in the circuit of Fig. 1. The waveforms 22 and 24 in Figs. 3A and 3B, respectively, illustrate the operation of the voltage multiplier 20. Figs. 4A-4D show different output pulse trains corresponding to four operational modes of the stimulator of Fig. 1. Pulses 30 in Fig. 4A are a train of four mode and pulses 32 in Fig. 4B are a tetanus mode. Pulses 34 in Fig. 4C are a twitch mode and pulses 36 in Fig. 4D are a double burst mode. These modes will be described in further detail presently. The curves 40, 42 and 44 in Fig. 5 illustrate output impedance characteristics for the stimulator of Fig. 1 in response to variation in operational parameters. Fig. 6 is an elevational view of the stimulator 10 of Fig. 1 contained in a rectangular housing 50. Output ball electrodes 52 and 54 are connected to terminals 16 and 18, respectively, of the circuit of Fig. 1. The apparatus includes a battery L.E.D. indicator 58 and an output stimulator pulse
L.E.D. indicator 60. An on-off switch for the apparatus is designated 62. The four modes of operation are controlled by twitch key 64, train of four key 66, double burst stimulation key 68 and tetanus key 70. The apparatus is intended for monitoring the effects of skeletal muscle relaxants in an MR or interventional MR environment, not to exceed a 1.5 Telsa field strength. It has been tested and shown to be safe and effective for normal use in a 1.5T GE Signa System. The apparatus is not intended to be used in the magnet bore while imaging due to potential distortion of the MR image . The four pulse stimulation modes previously described have the following characteristics. DOUBLE BURST is two groups of three 200uS impulses, pulses every 20mS, and groups separated by 1 second. TWITCH is 200uS pulses every 1 second continuous. TENANUS is 200 uS pulses every 20mS continuous. TRAIN-OF-FOUR is four 200uS pulses every 1/2 second.
The yellow pulse LED 60 flashes each time a pulse is generated. The green battery LED 58 indicates that the power is on, and the battery voltage is sufficient. The apparatus is powered by one Greatbatch Scientific Battery Pack No. GN-7B0194. Housing 50 can be high impact ABS plastic, 2.75" x 4.50" x 1.50". The apparatus has a weight of 11.3 oz . , including battery. The stimulator apparatus is controlled by the four push buttons or keys 64, 66, 68 and 70 on the case 50, and by the combination potentiometer control knob and switch 62 also on the case 50. The green LED 58, labeled BATTERY, indicates the power is on, and the battery voltage is sufficient. If the green BATTERY LED 58 does not light when the switch is turned on, the battery should be replaced. The yellow LED 60, labeled PULSE, indicates output impulses, and will flash each time an output stimulus pulse is generated. An audio indicator located inside the case 50 gives audio indication of output impulses along with the yellow LED 60. The device is activated by turning the potentiometer control knob 62 until a light click is heard. The maximum counter-clockwise position of the control knob is power off. The Potentiometer adjusts the amplitude of the impulses from zero to 400 Volts. The ball electrodes 52 and 54 are placed in direct contact with the patient.
The Double Burst Stimulation (DBS) button 68 delivers two groups of three impulses each. The impulses are 200 microseconds long, spaced 20 milliseconds apart within the group, with the groups spaced 1 second apart. The yellow PULSE LED 60, indicates the impulses being generated. Before the next group of impulses can be generated, the DBS button 68 must be released. Additional sets of pulses can be generated by depressing the DBS button 68.
The TWITCH button 64 delivers a continuous waveform of impulses 200 microseconds each, spaced 1 second apart as long as the button is depressed. The yellow PULSE LED 60 indicates the impulses are being generated.
The TETANUS button 70 delivers a continuous waveform of impulses 200 microseconds each, spaced 20 milliseconds apart as long as the button is depressed. The yellow PULSE LED 60 indicates the impulses are being generated.
The Train-of-Four (TOF) button 66 delivers a train of four impulses 200 microseconds each, spaced 500 milliseconds apart. The yellow PULSE LED 60 indicates the impulses are being generated. Depressing the button will deliver only a single train of four impulses.
Before the next group of impulses can be generated the TOF button 66 must be released. The series of train-of- four pulses can be repeated as often as one wishes by repeated depressing of the TOF button 66. The following is a brief description of clinical use of the magnetically compatible peripheral nerve stimulator of the present invention. One use involves the neuromuscular junction. The impulse passing down a motor nerve is transmitted to a muscle across the motor end plate or neuromuscular junction. The transmission of this impulse is medicated via acetylcholine which becomes attached to specific receptors sites on the motor end plate. In general terms, it is the blockade of transmission across the neuromuscular junction by muscle relaxants that produce muscle relaxations. Although all muscle relaxants act on the neuromuscular junction, the mode and duration of action and intensity of blockade differ for different agents. These specific aspects of the action of neuromuscular agents can be differentiated by nerve stimulation using the magnetically compatible peripheral nerve stimulator of the present invention.
Another use relates to depolarizing and non- depolarizing blockade. Physiological conduction across the neuromuscular junction is by depolarization of the motor end plate by acthycholine . This depolarization is of exceedingly short duration. Depolarizing relaxants such as succinylcholine chloride cause depolarization of the end plate but the recovery period is much greater and extends to minutes rather than milliseconds. Prolonged depolarization causes neuromuscular blockade. Non-depolarizing relaxants such as d-tubocurarine chloride do not cause depolarization; rather they occupy the specific receptor sites on the motor end plate. This prevents acetylcholine from attaching to the receptor sites. The duration of action of these drugs is probably dependent on how long they occupy the receptor sites. The difference in the type of blockade produced by the depolarizing or non-depolarizing relaxants accounts for their differing response to nerve stimulation, such as that provided by the magnetically compatible peripheral nerve stimulator of the present invention.
The magnetically compatible peripheral nerve stimulator of the present invention can be used in detection of the type of neuromuscular blockade. The response to a brief train of stimuli is a more sensitive index of receptor blockade by a competitive neuromuscular blocking agent than is the response to a single twitch. Also, the Train-of-Four stimulus may produce less discomfort in a conscious patient than a tetanic stimulus. Double Burst Stimulation (DBS) is a pattern of stimulation developed to reveal residual neuromuscular blockade. DBS was developed with the specific aim of allowing manual (tactile) detection of small amounts of residual neuromuscular blockade under clinical conditions.

Claims

We claim :
1. An electrical stimulation device for applying a stimulation signal to living tissue, the electrical stimulation device comprising: a non-magnetic power source that provides an electrical signal; an array of a first capacitor and a second capacitor in series and a first diode and a second diode in series to form a voltage multiplier, the voltage multiplier receives the electrical signal and multiplies the voltage of the electrical signal; and an electrode receives the multiplied signal and transmits the multiplied signal to the living tissue ; wherein the stimulation device is compatible with a magnetic resonance field.
2. The device of claim 1 wherein the electrical signal has its amplitude equal to the supply voltage.
3. The device of claim 1 wherein the power source is a lithium battery.
4. The device of claim 1 wherein the device is a hand-held instrument.
5. The device of claim 1 wherein the device depolarizes the living tissue.
6. The device of claim 1 wherein the device non-depolarizes the living tissue.
7. The device of claim 1 wherein the amplitude of the multiplied signal is adjustable.
8. The device of claim 1 wherein the device alters the transmission of the multiplied signal.
9. The device of claim 8 wherein the transmission is selected from the group consisting of tetanus mode, train of four mode, twitch mode and double burst mode .
10. The method of using an electrical stimulation device for applying a stimulation signal to living tissue, the method comprising the steps of: generating an electrical signal from a nonmagnetic power source; multiplying the voltage of the electrical signal in an array of a first capacitor and a second capacitor in series and a first diode and a second diode in series that form a voltage multiplier, the voltage multiplier receives the electrical signal and then multiplies the voltage of the electrical signal; and applying the multiplied signal to the living tissue through an electrode; wherein the stimulation device is compatible with a magnetic resonance field.
11. The method of claim 10 wherein the electrical signal has its amplitude equal to the supply voltage .
12. The method of claim 10 wherein the power source is a lithium battery.
13. The method of claim 10 wherein the device is a hand-held instrument.
14. The method of claim 10 wherein the device depolarizes the living tissue.
15. The method of claim 10 wherein the device non-depolarizes the living tissue.
16. The method of claim 10 wherein the amplitude of the multiplied signal is adjustable.
17. The method of claim 10 wherein the device alters the transmission of the multiplied signal.
18. The method of claim 17 wherein the transmission is selected from the group consisting of tetanus mode, train of four mode, twitch mode and double burst mode .
19. The method of claim 10 further comprising the step of monitoring the effects of skeletal muscle relaxants .
20. An non-magnetic hand-held electrical stimulation device for applying a stimulation signal to living tissue, the electrical stimulation device comprising : a non-magnetic lithium battery that provides an electrical signal; an array of a first capacitor and a second capacitor in series and a first diode and a second diode in series to form a voltage multiplier, the voltage multiplier receives the electrical signal and multiplies the voltage of the electrical signal; and an electrode receives the multiplied signal and transmits the multiplied signal to the living tissue in one of four modes, the four modes are selected from the group consisting of tetanus mode, train of four mode, twitch mode and double burst mode; wherein the stimulation device is compatible with a magnetic resonance field.
PCT/US1998/021834 1997-10-15 1998-10-15 Magnetically compatible peripheral nerve stimulator WO1999019020A1 (en)

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US60/063,996 1997-10-15

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US7684860B2 (en) 2006-03-24 2010-03-23 Medtronic, Inc. Components for reducing image distortion
US8989840B2 (en) 2004-03-30 2015-03-24 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US9044593B2 (en) 2007-02-14 2015-06-02 Medtronic, Inc. Discontinuous conductive filler polymer-matrix composites for electromagnetic shielding
US9155877B2 (en) 2004-03-30 2015-10-13 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US9186499B2 (en) 2009-04-30 2015-11-17 Medtronic, Inc. Grounding of a shield within an implantable medical lead
US9259572B2 (en) 2007-04-25 2016-02-16 Medtronic, Inc. Lead or lead extension having a conductive body and conductive body contact
US9302101B2 (en) 2004-03-30 2016-04-05 Medtronic, Inc. MRI-safe implantable lead
US9463317B2 (en) 2012-04-19 2016-10-11 Medtronic, Inc. Paired medical lead bodies with braided conductive shields having different physical parameter values
US9731119B2 (en) 2008-03-12 2017-08-15 Medtronic, Inc. System and method for implantable medical device lead shielding
US9993638B2 (en) 2013-12-14 2018-06-12 Medtronic, Inc. Devices, systems and methods to reduce coupling of a shield and a conductor within an implantable medical lead
US10084250B2 (en) 2005-02-01 2018-09-25 Medtronic, Inc. Extensible implantable medical lead
US10155111B2 (en) 2014-07-24 2018-12-18 Medtronic, Inc. Methods of shielding implantable medical leads and implantable medical lead extensions
US10279171B2 (en) 2014-07-23 2019-05-07 Medtronic, Inc. Methods of shielding implantable medical leads and implantable medical lead extensions
US10537730B2 (en) 2007-02-14 2020-01-21 Medtronic, Inc. Continuous conductive materials for electromagnetic shielding
US11083908B2 (en) 2016-01-19 2021-08-10 Epitech Mag Ltd. Enhancing epithelial integrity by a sequence of magnetic pulses
US11247065B2 (en) 2017-07-26 2022-02-15 Epitech Mag Ltd. Magnetic device for treating living tissues

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4917092A (en) * 1988-07-13 1990-04-17 Medical Designs, Inc. Transcutaneous nerve stimulator for treatment of sympathetic nerve dysfunction
US5217010A (en) * 1991-05-28 1993-06-08 The Johns Hopkins University Ecg amplifier and cardiac pacemaker for use during magnetic resonance imaging

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4917092A (en) * 1988-07-13 1990-04-17 Medical Designs, Inc. Transcutaneous nerve stimulator for treatment of sympathetic nerve dysfunction
US5217010A (en) * 1991-05-28 1993-06-08 The Johns Hopkins University Ecg amplifier and cardiac pacemaker for use during magnetic resonance imaging

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8989840B2 (en) 2004-03-30 2015-03-24 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US9302101B2 (en) 2004-03-30 2016-04-05 Medtronic, Inc. MRI-safe implantable lead
US9155877B2 (en) 2004-03-30 2015-10-13 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US10084250B2 (en) 2005-02-01 2018-09-25 Medtronic, Inc. Extensible implantable medical lead
US8548591B2 (en) 2006-03-24 2013-10-01 Medtronic Inc. Implantable medical device
US8923969B2 (en) 2006-03-24 2014-12-30 Medtronic, Inc. Implantable medical device
US9393408B2 (en) 2006-03-24 2016-07-19 Medtronic, Inc. Implantable medical device
US8131368B2 (en) 2006-03-24 2012-03-06 Medtronic, Inc. Implantable medical device with material for reducing MRI image distortion
US7927737B2 (en) * 2006-03-24 2011-04-19 Medtronic, Inc. Implantable medical device and lithium battery
US7684860B2 (en) 2006-03-24 2010-03-23 Medtronic, Inc. Components for reducing image distortion
US7890165B2 (en) 2006-03-24 2011-02-15 Medtronic, Inc. Implantable medical device with reduced MRI image distortion
US9044593B2 (en) 2007-02-14 2015-06-02 Medtronic, Inc. Discontinuous conductive filler polymer-matrix composites for electromagnetic shielding
US10537730B2 (en) 2007-02-14 2020-01-21 Medtronic, Inc. Continuous conductive materials for electromagnetic shielding
US10398893B2 (en) 2007-02-14 2019-09-03 Medtronic, Inc. Discontinuous conductive filler polymer-matrix composites for electromagnetic shielding
US9259572B2 (en) 2007-04-25 2016-02-16 Medtronic, Inc. Lead or lead extension having a conductive body and conductive body contact
US9731119B2 (en) 2008-03-12 2017-08-15 Medtronic, Inc. System and method for implantable medical device lead shielding
US9272136B2 (en) 2009-04-30 2016-03-01 Medtronic, Inc. Grounding of a shield within an implantable medical lead
US9216286B2 (en) 2009-04-30 2015-12-22 Medtronic, Inc. Shielded implantable medical lead with guarded termination
US9186499B2 (en) 2009-04-30 2015-11-17 Medtronic, Inc. Grounding of a shield within an implantable medical lead
US9629998B2 (en) 2009-04-30 2017-04-25 Medtronics, Inc. Establishing continuity between a shield within an implantable medical lead and a shield within an implantable lead extension
US9220893B2 (en) 2009-04-30 2015-12-29 Medtronic, Inc. Shielded implantable medical lead with reduced torsional stiffness
US9205253B2 (en) 2009-04-30 2015-12-08 Medtronic, Inc. Shielding an implantable medical lead
US10035014B2 (en) 2009-04-30 2018-07-31 Medtronic, Inc. Steering an implantable medical lead via a rotational coupling to a stylet
US9452284B2 (en) 2009-04-30 2016-09-27 Medtronic, Inc. Termination of a shield within an implantable medical lead
US10086194B2 (en) 2009-04-30 2018-10-02 Medtronic, Inc. Termination of a shield within an implantable medical lead
US9463317B2 (en) 2012-04-19 2016-10-11 Medtronic, Inc. Paired medical lead bodies with braided conductive shields having different physical parameter values
US9993638B2 (en) 2013-12-14 2018-06-12 Medtronic, Inc. Devices, systems and methods to reduce coupling of a shield and a conductor within an implantable medical lead
US10279171B2 (en) 2014-07-23 2019-05-07 Medtronic, Inc. Methods of shielding implantable medical leads and implantable medical lead extensions
US10155111B2 (en) 2014-07-24 2018-12-18 Medtronic, Inc. Methods of shielding implantable medical leads and implantable medical lead extensions
US11083908B2 (en) 2016-01-19 2021-08-10 Epitech Mag Ltd. Enhancing epithelial integrity by a sequence of magnetic pulses
US11247065B2 (en) 2017-07-26 2022-02-15 Epitech Mag Ltd. Magnetic device for treating living tissues

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