INTRODUCER SHEATH WITH ELECTRODES

• US 20120220848A1
• Filed: 05/10/2012
• Published: 08/30/2012
• Est. Priority Date: 01/04/2008
• Status: Active Grant

• Current Assignee: Texas Heart Institute
• Original Assignee: Texas Heart Institute
• Inventors: Razavi, Mehdi, Arevalos, Christopher Alexander, Brewer, Maurice Alan
• Granted Patent: US 9,078,627 B2
• Time in Patent Office: Days
• US Class Current: 600/371
• CPC Class Codes: A61B 5/02042 Determining blood loss or bleeding, e.g. during a surgical procedure
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/07 Endoradiosondes
• CPC Class Codes: A61B 5/6851 Guide wires
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/6885 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61M 25/0662 Guide tubes

Abstract

An introducer comprise a sheath for introducing a catheter into a blood vessel, a plurality of electrodes on the sheath, and an impedance assessment unit provided on the sheath and connected to the electrodes. The impedance assessment unit fixes one of a current or voltage across a first pair of the electrodes and measures the other of the current or voltage across a second pair of electrodes.

Claims

1. An introducer, comprising:

a sheath for introducing a catheter into a blood vessel;

a plurality of electrodes on the sheath; and

an impedance assessment unit provided on said sheath and connected to said electrodes, said impedance assessment unit fixes one of a current or voltage across a first pair of the electrodes and measures the other of the current or voltage across a second pair of electrodes.

2. The introducer of claim 1 wherein the impedance assessment unit includes a wireless transmitter.

3. The introducer of claim 2 wherein the impedance assessment unit wirelessly transmits the measured current or voltage to an external device.

4. The introducer of claim 1 wherein the impedance assessment unit computes impedance based on the current and voltage.

5. The introducer of claim 4 wherein the impedance assessment unit includes a wireless transmitter and wirelessly transmits the computed impedance to an external device.

6. The introducer of claim 1 wherein the impedance assessment unit includes a power source.

7. The introducer of claim 1 wherein the fixed current or voltage is an alternating current (AC) current or voltage.

8. The introducer of claim 7 wherein the impedance assessment unit initiates multiple impedance measurements by serially fixing the current or voltage at various pre-defined frequencies while simultaneously measuring the other of the current or voltage.

9. The introducer of claim 8 wherein the impedance measurement unit computes impedances based on multiple currents and voltages, and compares each computed impedance to a baseline impedance.

10. The introducer of claim 1 wherein a magnitude or frequency of the fixed current or voltage is variable by the impedance assessment unit.

11. The introducer of claim 1 wherein the impedance assessment unit includes a bi-directional wireless transceiver that receives a signal from an external device and transmits a value indicative of impedance to the external device.

12. The introducer of claim 11 wherein the received signal includes a command to take an impedance measurement.

13. The introducer of claim 11 wherein the received signal includes a command to program an amplitude or frequency of the fixed current or voltage.

14. The introducer of claim 1 wherein the transmitted value is at least one of current, voltage, and impedance.

15. The introducer of claim 11 wherein the impedance assessment unit transmits an alert signal upon detecting a change in current, voltage or impedance over time that is greater than a threshold.

16. The introducer of claim 1 wherein the impedance assessment unit makes a plurality of impedance measurements and averages the measurements together.

17. The introducer of claim 1 wherein the impedance assessment unit computes an impedance value and compares the computed impedance value to a previously computed impedance value.

18. The introducer of claim 17 wherein the impedance assessment unit computes the time rate of change of the computed impedance value relative to a previously computed impedance value.

19. The introducer of claim 1 further comprising an indicator activated by the impedance assessment unit upon detection that an impedance value or time rate of change of the impedance value exceeds a threshold.

20. The introducer of claim 19 wherein the indicator is at least one of a visual indicator and an audible indicator.

21. The introducer of claim 1 wherein the impedance assessment unit comprises a current source and a voltage monitor.

22. The introducer of claim 1 wherein the impedance assessment unit comprises a voltage source and a current monitor.

23. The introducer of claim 1 wherein sheath has a hub and the impedance assessment unit is provided in the hub.

24. An introducer, comprising:

a sheath for introducing a catheter into a blood vessel;

a plurality of electrodes on the sheath; and

an impedance assessment unit provided on said sheath and connected to said electrodes, said impedance assessment unit includes a wireless transceiver and fixes one of a current or voltage across a first pair of the electrodes and measures the other of the current or voltage across a second pair of electrodes;

wherein the impedance assessment unit transmits a value indicative of impedance to an external apparatus.

25. The introducer of claim 24 wherein the impedance assessment unit comprises a controller, a source unit and a measurement unit, wherein the controller causes the source unit to provide a fixed current or voltage to the first pair of electrodes and receives from the measurement unit a measured value of the current or voltage.

26. The introducer of claim 25 wherein the controller initiates impedance measurements at multiple different frequencies.

27. The introducer of claim 25 wherein the controller receives a command via the wireless transceiver to initiate an impedance measurement.