Galvanic isolation of a medical apparatus

• US 20070073175A1
• Filed: 09/29/2005
• Published: 03/29/2007
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: Welch Allyn Incorporated
• Original Assignee: Welch Allyn Incorporated
• Inventors: McAtamney, Michael, Melquist, John, Kroetz, John, Ruizenaar, Rudolf, Sommers, Daniel, Looije, Alexius, Shortt, Jim
• Granted Patent: US 7,618,377 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/301 providing electrical separation, e.g. by using isolating transformers or optocouplers
• CPC Class Codes: A61B 5/308 for electrocardiography [ECG]

Abstract

A medical device, such as an electrocardiogram (ECG) monitoring apparatus, provides galvanic isolation between low voltage electronics and a plurality of externally exposed ECG (patient contact) lead wires and electrodes. The ECG lead wires and/or electrodes can potentially make unwanted contact with sources of high voltage, such as from defibrillation pulses generated by defibrillation devices. The defibrillation pulses can cause damage to the low voltage electronics within the ECG monitoring apparatus. Electrical resistance is provided outside of the ECG lead wires and electrodes and separate from the low voltage electronics to protect against misdirection of a defibrillation pulse towards the low voltage electronics, and to protect against misdirection of a defibrillation pulse away from the patient for which the benefit of the defibrillation pulse is intended.

Claims

1. A medical apparatus that is configured for providing compact storage of, and electrical isolation between, each of a plurality of signal conductive pathways, comprising:

a front conductive pathway that includes a first and a second end, said first end is configured to be disposed proximate to and to receive electrical signals that are associated with a patient, said second end is configured to make electrical contact with a first end of a rear conductive pathway, said front conductive pathway is detachable from and re-attachable to said rear conductive pathway via an electrical connection located within a housing;

said rear conductive pathway includes a second end that is configured to make electrical contact with electronics that are configured to process said signals, said rear conductive pathway includes a resistor that is located between said first end and said second end of said rear conductive pathway and that is configured to protect said electronics from damaging effects of a voltage surge traveling through said front conductive pathway and into said rear conductive pathway.

2. The apparatus of claim 1 where said front conductive pathway excludes a resistor that is configured to protect said electronics from damaging effects of a voltage surge traveling through said front conductive pathway.

3. The apparatus of claim 1 where said housing includes at least one passageway and where said passageway is configured to enclose an electrically conductive pathway segment including said resistor and said connection between said front and said rear conductive pathways, and where internal structures located within said housing are configured to electrically isolate said electrically conductive pathway segment from other electrically conductive pathways that are located outside of said passageway.

4. The apparatus of claim 3 where said apparatus includes a plurality of front conductive pathways and where said housing includes a plurality of said passageways and where each of said plurality of said passageways enclose an instance of said conductive pathway segment including said portion of each said front conductive pathway and a portion of a respective and separate rear conductive pathway.

5. The apparatus of claim 4 where each of said plurality of passageways is bounded by insolating structures within said housing which are configured to electrically isolate each said conductive pathway segment that is located within each said passageway from another conductive pathway segment that is located within another passageway residing within said housing.

6. The apparatus of claim 1 where said voltage surge is generated from a defibrillation shock.

7. The apparatus of claim 3 where a contact pin is attached to said first end of said rear conductive pathway and mechanically supported in a stationary position within said passageway.

8. The apparatus of claim 7 where said contact pin includes a longitudinal axis and a flat surface that is substantially parallel to said longitudinal axis, said flat surface is configured to correctly orient and seat said contact pin within a recess within said passageway, said recess includes a flat interior surface that is configured to mate with said flat surface of said contact pin.

9. The apparatus of claim 3 where said passageway includes a barrel recess that provides a void within which said resistor of said rear conductive pathway is located.

10. The apparatus of claim 9 where said barrel recess is configured to accommodate a variety of resistor sizes that are configured to protect said electronics from damaging effects of a voltage surge.

11. The apparatus of claim 4 where said isolating structures are implemented as plastic baffles that are located between said pairs of said plurality of passageways.

12. The apparatus of claim 11 where said plastic baffles are manufactured via injection molding.

13. The apparatus of claim 1 where said electronics includes a printed circuit board (PCB) and where said second end is electrically connected to said PCB.

14. The apparatus of claim 13 where said PCB includes a passageway and where a portion of said rear conductive pathway is disposed within said passageway.

15. The apparatus of claim 7 where a patient lead electrode is configured to make electrical contact with said first end of said front conductive pathway and where said second end of said front conductive pathway is configured to make electrical contact with said contact pin.

16. The apparatus of claim 15 where said second end of said front conductive pathway is configured as a female type of electrical connector.

17. The apparatus of claim 1 where said apparatus is configured to function as a medical device that includes low voltage electronics having an electrical connection to a conductive path that can make unwanted contact with outside sources of electrical energy.

18. The apparatus of claim 1 where said apparatus is configured to function as an electrocardiogram (ECG) monitoring device and said signals are ECG signals.

19. The apparatus of claim 1 where said apparatus is configured receive signals from a transducer.

20. An method for providing compact storage of, and electrical isolation between, each of a plurality of ECG signal conductive pathways, comprising the steps of:

providing a front conductive pathway and a rear conductive pathway, said front conductive pathway includes a first and a second end, said first end is configured to be disposed proximate to and to receive ECG signals from a patient, said second end is configured to make electrical contact with a first end of said rear conductive pathway, said front conductive pathway is detachable from and re-attachable to said rear conductive pathway via an electrical connection located within a housing; and

where said rear conductive pathway includes a second end that is configured to make electrical contact with electronics that are configured to process said ECG signals, said rear conductive pathway includes a resistor that is located between said first end and said second end of said rear conductive pathway and that is configured to protect said electronics from damaging effects of a voltage surge traveling through said front conductive pathway and into said rear conductive pathway.