US3742947A - Optically isolated electro-medical device - Google Patents

Optically isolated electro-medical device Download PDF

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Publication number
US3742947A
US3742947A US00175121A US3742947DA US3742947A US 3742947 A US3742947 A US 3742947A US 00175121 A US00175121 A US 00175121A US 3742947D A US3742947D A US 3742947DA US 3742947 A US3742947 A US 3742947A
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United States
Prior art keywords
patient
circuitry
transistor
amplifier
light
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Expired - Lifetime
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US00175121A
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English (en)
Inventor
J Hashem
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American Optical Corp
Warner Lambert Co LLC
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American Optical Corp
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Assigned to COOK PACEMAKER CORPORATION reassignment COOK PACEMAKER CORPORATION LICENSE (SEE DOCUMENT FOR DETAILS). EFFECTIVE 03/27/81 Assignors: ATLANTIC RICHFIELD COMPANY
Assigned to WARNER LAMBERT COMPANY A CORP. OF DE reassignment WARNER LAMBERT COMPANY A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: AMERICAN OPTICAL CORPORATION A CORP. OF DE
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/04—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only
    • H03F3/08—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only controlled by light
    • H03F3/087—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only controlled by light with IC amplifier blocks
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
    • A61B5/30—Input circuits therefor
    • A61B5/301—Input circuits therefor providing electrical separation, e.g. by using isolating transformers or optocouplers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
    • A61B5/30—Input circuits therefor
    • A61B5/307—Input circuits therefor specially adapted for particular uses
    • A61B5/308—Input circuits therefor specially adapted for particular uses for electrocardiography [ECG]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S128/00—Surgery
    • Y10S128/908—Patient protection from electric shock

Definitions

  • Patent 1191 Hashem OPTICALLY ISOLATED ELECTRO-MEDICAL DEVICE [75] Inventor: James F. Hashem, Malden, Mass.
  • ABSTRACT An optically isolated electro-medical device.
  • An electronic device is disclosed that is used for monitoring physiological functions of a patient.
  • the device is electrically connected to the patient and establishes electrical isolation from other patient-connected circuitry by optical coupling.
  • the isolation substantially reduces the hazards of electrocuting a hospitalized, bed-ridden patient who may be connected to several different pieces of electro-medical equipment simultaneously.
  • the optical coupling includes a light-emitting diode in operative connection with a light-sensing transistor (photo-transistor) and is arranged to minitor the EKG of a patient.
  • a light-sensing transistor photo-transistor
  • This invention relates to electro-medical equipment, and more particularly relates to monitoring equipment which is electrically conductively connected to a patient but is electrically isolated from: (1.) other circuitry necessary to provide a usable output and (2.) other simultaneously connected electro-medical equipment.
  • the patent also discloses a high-speed relay switch that closes upon external electrical command to provide a conductive path. Ordinarily, the relay switch remains open to provide isolation.
  • This relay switch scheme of isolation does not permit linear coupling of signal between the isolated command and stimulator circuits.
  • linear coupling is not needed in a heart stimulator (the shape of the heart stimulation pulse is not at all that critical). But,,,by contrast, substantially linear coupling is required for accurate monitoring and the present invention provides such coupling.
  • a problem may arise when monitoring a patient in a hospital bed when that patient is electrically connected to several independent pieces of electronic apparatus.
  • a heart monitor and a respiration monitor may be connected simultaneously to the patient where both monitors are powered from line voltage. If the equipment is not grounded properly, the patient may be placed in a ground loop. This could be a dangerous situation where the patient may be electrically shocked by current flow from one piece of equipment to another through the patient.
  • stray ground loop currents flowing through the heart can kill the patient.
  • the present invention is a solution to the isolation problem of electro-medical monitoring apparatus.
  • the present invention includes optical coupling to provide electrical isolation.
  • An illustrative embodiment of the present invention is arranged to work with an ECG signal from the heart of a patient.
  • a preamplifier receives and amplifies the ECG signal from the patients heart.
  • the output of the amplifier is used to modulate current flowing a lightemitting diode. All of this patient-connected circuitry is powered by an isolated power supply such as a battery or an output from a DC to DC converter.
  • the modulated light-emitting diode provides a lightenergy output that linearly varies in intensity with modulating signal.
  • the remaining monitoring circuitry is electrically isolated from the patient-connected circuitry. It is powered from a second battery or a conventional regulated power supply.
  • the circuitry includes a photo-coupled device such as a photo-transistor.
  • the photo-trasistor receives a light input from the lightemitting diode and provides an electrical input to the remaining circuitry.
  • electrical isolation of the signal path is accomplished by optical coupling and electrical isolation of the power supplies is accomplished by using a DC to DC converter.
  • An advantage of the present invention is that it provides a simple and efficient way to monitor electrical signals representative of physiological functions of the body without danger of electrical shock.
  • a further advantage of the present invention is an inherent increase in reliability over other isolation schemes because of the few number of components used herein.
  • FIG. 1 is a schematic diagram of an illustrative embodiment of the present invention.
  • FIG.'2 is a block diagram of a power supply to be used in conjunction with the present invention.
  • the circuitry to the left of reference line 40 is hereafter referred to as patient-connected circuitry.
  • the circuitry to the right of reference line 40 is hereafter referred to as optically coupled circuitry.
  • the patient-connected circuitry is electrically isolated from the optically coupled circuitry as will be explained herein below.
  • Electrode 10 and 11 are attached between the patient (not shown) being monitored and the input to amplifier A Electrode 12 is connected between the patient and isolated ground 13, about which ground additional description is presented in succeeding paragraphs.
  • the output of amplifier A is coupled via conductor 14 to the base of transistor 15.
  • the emitter of transistor 15 is connected to one end of resistor 16, the other end being connected to isolated negative 15 volts (-l5 V
  • the collector of transistor 15 iss connected to the cathode side of light-emitting diode (LED) 17, the anode of whicl is connected to isolated positive 15 volts (+15 I V,).
  • LED light-emitting diode
  • Amplifier A is powered by V Optical coupling from the patient-connected circuitry to the optically coupled circuitry is depicted by light energy symbol l8.
  • Photo-transistor 19' is influenced by incident light energy 18.
  • Light-emitting diode 17 and photo-transistor 19 may both be encapsulated together and this is depicted by block 28 representing a photocoupled device.
  • the collector of photo-transistor 19 is connected to positive 15 volts (+15 V).
  • the emitter of transistor 19 is connected to both capacitor 21 and one end of resistor 20.
  • the other end of resistor 20 is connected to third wire ground 23. This ground differs from isolated ground 13 and will be explained more fully elow.
  • the other side of capacitor 21 is connected to an input of amplifier A and to one end of resistor 22.
  • the other end of resistor 22 is connected to third wire ground 23.
  • the output of amplifier A is obtained on terminal 27.
  • Resistors 24 and 26, and potentiometer 25 are in a series connections between the output of amplifier A and third wire ground 23.
  • the wiper of potentiometer 25 is conductively connected to another input of amplifier A as a feedback path.
  • Amplifier A is powered by 1-15 V.
  • DC to DC converter and regulated power supply 31 are shown as having various DC outputs and grounds. The voltages and grounds shown correspond to those shown in FIG. 1.
  • DC to DC converter 30 is the power supply for the patient-connected circuitry of FIG. 1, is commerically available, and is of conventional design.
  • DC to DC converter 30 is powered by a conventional regulated power supply 31 which provides +15 V and 1S V inputs to converter 30.
  • supply 31 is powered by ll5 rrns power.
  • Supply 31 is the power supply for the optically coupled circuitry.
  • the circuitry internal to converter 30 includes transformer circuitry which provides Isolation between the various inputs and outputs.
  • the voltage outputs +15 V,, -1 5 V,, and ground 13 are electrically isolated from voltage outputs +15 V, l5 V, and third wire ground 23.
  • current flow was less than 1 microampere when 115 volts RMS was applied between any 15 V terminal (either or and any 15 V, terminal (again, either or or between isolated ground 13 and third wire ground 23.
  • the monitored signal (in this case, an EKG signal but could be other signals) is fed to the input of amplifier A via terminals 10, 11 and 12.
  • the signal is amplified in amplifier A and the output of A is applied to the base of transistor 15.
  • Transistor 15 permits current flow there-through in accordance with the electrical signal input on its base. Current flows from +15 V, through the series circuit of LED 17, transistor 15, and resistor 16 to l 5 V,. The flow of current through LED 17 causes emission of light 18 which is the optical or light input to photo-transistor 19.
  • the variation of current or voltage applied to the base of transistor 15 is linearly related to the current flow through LED 17.
  • the current flow through LED 17 is linearly related to the intensity of light 18 that is emitted.
  • the intensity of light 18 is linearly related to the flow of current through photo-transistor 19.
  • an electrical signal in the circuitry to the right of line 40 linearly corresponds to the electrical signal in the circuitry to the left of line 40.
  • the signals are connected or coupled by light-intensity variations. Electrical isolation is achieved to the extent that in equipment constructed in accordance with the principles of the present invention less than 5.0 microamperes typically will flow when l 15 volts RMS is applied between any combination of input electrode terminals 10, 11, 12 and third wire ground 23 in FIG. 1.
  • Variations of current flow through photo-transistor 19 create voltage variations across resistor 20.
  • This voltage variation, or signal is A.C. coupled through capacitor 21, which removes any D.C. component.
  • the resultant A.C. signal is equivalent to the signal obtained on terminals 10, 11, and 12 and is applied-to amplifier A
  • the amplitude of the signal is controlled by setting feedback potentiometer 25 as desired. It should be understood that amplifiers A and A may comprise considerable circuitry and may not necessarily be a single transistor or amplifying device.
  • amplifier A is a preamplifier which amplifies an ECG signal from the patient.
  • the output of A feeds the base of transistor 15 which amplitude modulates the current passing through light-emitting diode 17. Because of the properties of light-emitting diodes, modulating this current modulates the light being emitted by light-emitting diode 17.
  • This modulated light 18 is sensed by photo-transistor l9 in'side photo-coupled device 28. Photo-transistor l9 reconverts modulated light 18 into modulated current.
  • the modulated current develops signal voltage across resistor 20, which is a reconverted ECG signal. It is then coupled through capacitor 21 to remove any DC component, and amplified by amplifier A which makes up for any loss of signal amplitude.
  • A also acts as a buffer amplifier to increase output drive capabIlity.
  • the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.
  • ultrasonic coupling may be substituted for optical coupling, the substitution incorporating appropriate circuitry changes.
  • a single piezoelectric crystal could be used with two pairs of electrical connectionsone pair conductively connected to the patient and electrically isolated from the other pair conductively connected to the other equipment or apparatus.
  • optical coupling means comprising a light-emitting 5 diode in operative connection with a phototransistor for electrically isolating the output signal of said amplifier from said plurality of other electrical apparatus and for linearly coupling said output signal to at least one of said plurality of other electrical apparatus,

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Molecular Biology (AREA)
  • General Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Physics & Mathematics (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • Biophysics (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Cardiology (AREA)
  • Measuring And Recording Apparatus For Diagnosis (AREA)
  • Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
  • Amplifiers (AREA)
  • Electrotherapy Devices (AREA)
US00175121A 1971-08-26 1971-08-26 Optically isolated electro-medical device Expired - Lifetime US3742947A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US17512171A 1971-08-26 1971-08-26

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US00175121A Expired - Lifetime US3742947A (en) 1971-08-26 1971-08-26 Optically isolated electro-medical device

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US (1) US3742947A (de)
JP (1) JPS4832390A (de)
CA (1) CA995761A (de)
DE (1) DE2236002A1 (de)
GB (1) GB1363196A (de)

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3825896A (en) * 1972-05-01 1974-07-23 Texas Instruments Inc Computer input/output interface systems using optically coupled isolators
US3880146A (en) * 1973-06-04 1975-04-29 Donald B Everett Noise compensation techniques for bioelectric potential sensing
US3894229A (en) * 1972-07-28 1975-07-08 Matsushita Electric Ind Co Ltd Signal generator
US3912951A (en) * 1973-04-19 1975-10-14 Nippon Electric Co Optically coupled circuit arrangement
US4211934A (en) * 1976-07-08 1980-07-08 Bbc Brown Boveri & Company Limited Current-measuring input for an electronic relay
US4384775A (en) * 1980-03-19 1983-05-24 Olympus Optical Co., Ltd. Light supply device for an endoscope
US4715384A (en) * 1982-02-03 1987-12-29 Kabushiki Kaisha Daini Seikosha Pulsimeter
US4752693A (en) * 1983-03-31 1988-06-21 Tokyo Shibaura Denki Kabushiki Kaisha Circuit with a photo coupler
US4976681A (en) * 1988-04-27 1990-12-11 Aries Medical, Inc. Pacer interface device
US4987902A (en) * 1988-12-30 1991-01-29 Physio-Control Corporation Apparatus for transmitting patient physiological signals
US5108389A (en) * 1990-05-23 1992-04-28 Ioan Cosmescu Automatic smoke evacuator activator system for a surgical laser apparatus and method therefor
US5226431A (en) * 1991-06-20 1993-07-13 Caliber Medical Corporation Optical/electrical transceiver
US5307817A (en) * 1989-01-27 1994-05-03 Medese Ag Biotelemetry method for the transmission of bioelectric potential defferences, and a device for the transmission of ECG signals
US5322069A (en) * 1991-11-12 1994-06-21 Stuart Medical Inc. Ambulatory ECG triggered blood pressure monitoring system and method therefor
US5522865A (en) * 1989-09-22 1996-06-04 Alfred E. Mann Foundation For Scientific Research Voltage/current control system for a human tissue stimulator
US5626619A (en) * 1993-10-08 1997-05-06 Jacobson; Peter Optically isolated shock circuit for implantable defibrillator
US5680104A (en) * 1996-05-31 1997-10-21 Volution Fiber optic security system
US6391102B1 (en) 2000-03-21 2002-05-21 Stackhouse, Inc. Air filtration system with filter efficiency management
US6493485B1 (en) 1999-08-03 2002-12-10 Astro Terra Corporation Systems and methods for aligning a laser beam with an optical fiber
US20040160719A1 (en) * 2003-02-18 2004-08-19 Adc Dsl Systems, Inc. High-speed isolated port
EP1494124A2 (de) * 2003-06-30 2005-01-05 Becton Dickinson and Company Selbstgespeistes seriell-serielles oder USB-serielles Kabel mit Rückkopplung und Isolierung
US20080294046A1 (en) * 1995-06-29 2008-11-27 Teratech Corporation Portable ultrasound imaging system
US20080300490A1 (en) * 1995-06-29 2008-12-04 Teratech Corporation Portable ultrasound imaging system
US20090112091A1 (en) * 1995-06-29 2009-04-30 Teratech Corporation Portable ultrasound imaging data
WO2009126384A1 (en) * 2008-04-10 2009-10-15 Smiths Medical Md, Inc. Ambulatory medical device with electrical isolation from connected peripheral device
US20100169513A1 (en) * 2008-12-31 2010-07-01 Fresenius Medical Care Holdings, Inc. Identifying A Self-Powered Device Connected To A Medical Device
US20100168653A1 (en) * 2008-12-31 2010-07-01 Fresenius Medical Care Holdings, Inc. Identifying a Self-Powered Device Connected to a Medical Device

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5098584U (de) * 1974-01-11 1975-08-16
JPS50119484A (de) * 1974-03-06 1975-09-18
JPS55145956A (en) * 1979-04-24 1980-11-13 Nippon Telegr & Teleph Corp <Ntt> Method of correcting meandering
JPS61178357A (ja) * 1985-01-30 1986-08-11 Graphtec Corp 用紙自動整列装置
JPS63272325A (ja) * 1986-12-19 1988-11-09 Fukuda Denshi Co Ltd 生体信号処理装置
JPS63272324A (ja) * 1986-12-19 1988-11-09 Fukuda Denshi Co Ltd 生体信号処理装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3488586A (en) * 1965-06-02 1970-01-06 Gen Electric Frequency modulated light coupled data link
US3598909A (en) * 1967-07-25 1971-08-10 Matsushita Electric Ind Co Ltd A high-voltage generator circuit configuration utilizing a ceramic transformer

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3488586A (en) * 1965-06-02 1970-01-06 Gen Electric Frequency modulated light coupled data link
US3598909A (en) * 1967-07-25 1971-08-10 Matsushita Electric Ind Co Ltd A high-voltage generator circuit configuration utilizing a ceramic transformer

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Kebo, I.E.E.E. Transactions on Biomedical Electronics, Vol. 17, No. 2, April, 1970, pp. 163 166 *
Van der Weide et al., Medical & Biological Engineering, Vol. 6, No. 4, August, 1968, pp. 447 and 448 *

Cited By (41)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3825896A (en) * 1972-05-01 1974-07-23 Texas Instruments Inc Computer input/output interface systems using optically coupled isolators
US3894229A (en) * 1972-07-28 1975-07-08 Matsushita Electric Ind Co Ltd Signal generator
US3912951A (en) * 1973-04-19 1975-10-14 Nippon Electric Co Optically coupled circuit arrangement
US3880146A (en) * 1973-06-04 1975-04-29 Donald B Everett Noise compensation techniques for bioelectric potential sensing
US4211934A (en) * 1976-07-08 1980-07-08 Bbc Brown Boveri & Company Limited Current-measuring input for an electronic relay
US4384775A (en) * 1980-03-19 1983-05-24 Olympus Optical Co., Ltd. Light supply device for an endoscope
US4715384A (en) * 1982-02-03 1987-12-29 Kabushiki Kaisha Daini Seikosha Pulsimeter
US4752693A (en) * 1983-03-31 1988-06-21 Tokyo Shibaura Denki Kabushiki Kaisha Circuit with a photo coupler
US4976681A (en) * 1988-04-27 1990-12-11 Aries Medical, Inc. Pacer interface device
US4987902A (en) * 1988-12-30 1991-01-29 Physio-Control Corporation Apparatus for transmitting patient physiological signals
US5307817A (en) * 1989-01-27 1994-05-03 Medese Ag Biotelemetry method for the transmission of bioelectric potential defferences, and a device for the transmission of ECG signals
US5522865A (en) * 1989-09-22 1996-06-04 Alfred E. Mann Foundation For Scientific Research Voltage/current control system for a human tissue stimulator
US5108389A (en) * 1990-05-23 1992-04-28 Ioan Cosmescu Automatic smoke evacuator activator system for a surgical laser apparatus and method therefor
US5226431A (en) * 1991-06-20 1993-07-13 Caliber Medical Corporation Optical/electrical transceiver
US5322069A (en) * 1991-11-12 1994-06-21 Stuart Medical Inc. Ambulatory ECG triggered blood pressure monitoring system and method therefor
US5568814A (en) * 1991-11-12 1996-10-29 Protocol Systems, Inc. Ambulatory patient monitoring system
US5626619A (en) * 1993-10-08 1997-05-06 Jacobson; Peter Optically isolated shock circuit for implantable defibrillator
US8469893B2 (en) 1995-06-29 2013-06-25 Teratech Corp. Portable ultrasound imaging system
US8628474B2 (en) 1995-06-29 2014-01-14 Teratech Corporation Portable ultrasound imaging system
US20080300490A1 (en) * 1995-06-29 2008-12-04 Teratech Corporation Portable ultrasound imaging system
US8241217B2 (en) 1995-06-29 2012-08-14 Teratech Corporation Portable ultrasound imaging data
US20090112091A1 (en) * 1995-06-29 2009-04-30 Teratech Corporation Portable ultrasound imaging data
US20080294046A1 (en) * 1995-06-29 2008-11-27 Teratech Corporation Portable ultrasound imaging system
US5680104A (en) * 1996-05-31 1997-10-21 Volution Fiber optic security system
US6493485B1 (en) 1999-08-03 2002-12-10 Astro Terra Corporation Systems and methods for aligning a laser beam with an optical fiber
US6391102B1 (en) 2000-03-21 2002-05-21 Stackhouse, Inc. Air filtration system with filter efficiency management
US20040160719A1 (en) * 2003-02-18 2004-08-19 Adc Dsl Systems, Inc. High-speed isolated port
US6977540B2 (en) * 2003-02-18 2005-12-20 Adc Dsl Systems, Inc. High-speed isolated port
US20050001179A1 (en) * 2003-06-30 2005-01-06 Scott Gisler Self powered serial-to-serial or USB-to-serial cable with loopback and isolation
US9529762B2 (en) 2003-06-30 2016-12-27 Becton, Dickinson And Company Self powered serial-to-serial or USB-to-serial cable with loopback and isolation
EP1494124A3 (de) * 2003-06-30 2006-09-06 Becton Dickinson and Company Selbstgespeistes seriell-serielles oder USB-serielles Kabel mit Rückkopplung und Isolierung
EP1494124A2 (de) * 2003-06-30 2005-01-05 Becton Dickinson and Company Selbstgespeistes seriell-serielles oder USB-serielles Kabel mit Rückkopplung und Isolierung
WO2009126384A1 (en) * 2008-04-10 2009-10-15 Smiths Medical Md, Inc. Ambulatory medical device with electrical isolation from connected peripheral device
US20090256527A1 (en) * 2008-04-10 2009-10-15 Michael Welsch Ambulatory medical device with electrical isolation from connected peripheral device
US8716979B2 (en) 2008-04-10 2014-05-06 Smiths Medical Asd, Inc. Ambulatory medical device with electrical isolation from connected peripheral device
US8030891B2 (en) 2008-04-10 2011-10-04 Smiths Medical Asd, Inc. Ambulatory medical device with electrical isolation from connected peripheral device
US8135876B2 (en) * 2008-12-31 2012-03-13 Fresenius Medical Care Holdings, Inc. Identifying when a USB self-powered device is connected to a medical device by triggering an alert about a potential risk to patient
US8255585B2 (en) 2008-12-31 2012-08-28 Fresenius Medical Care Holdings, Inc. Identifying when a self-powered device is connected to a medical device by triggering an alert about a potential risk to patient
US8145800B2 (en) 2008-12-31 2012-03-27 Fresenius Medical Card Holdings, Inc. Identifying when a USB self-powered device is connected to a medical device by triggering an alert about a potential risk to patient
US20100168653A1 (en) * 2008-12-31 2010-07-01 Fresenius Medical Care Holdings, Inc. Identifying a Self-Powered Device Connected to a Medical Device
US20100169513A1 (en) * 2008-12-31 2010-07-01 Fresenius Medical Care Holdings, Inc. Identifying A Self-Powered Device Connected To A Medical Device

Also Published As

Publication number Publication date
DE2236002A1 (de) 1973-03-01
GB1363196A (en) 1974-08-14
JPS4832390A (de) 1973-04-28
CA995761A (en) 1976-08-24

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Owner name: COOK PACEMAKER CORPORATION, INDIANA

Free format text: LICENSE;ASSIGNOR:ATLANTIC RICHFIELD COMPANY;REEL/FRAME:003852/0285

Effective date: 19810327

Owner name: COOK PACEMAKER CORPORATION, P.O. BOX 99, BLOOMINGT

Free format text: LICENSE;ASSIGNOR:ATLANTIC RICHFIELD COMPANY;REEL/FRAME:003852/0285

Effective date: 19810327

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Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:AMERICAN OPTICAL CORPORATION A CORP. OF DE;REEL/FRAME:004054/0502

Effective date: 19820315