Devices and methods for measuring temperature of a patient

• US 6,383,144 B1
• Filed: 01/18/2000
• Issued: 05/07/2002
• Est. Priority Date: 01/18/2000
• Status: Expired due to Term

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Edwards Lifesciences Corporation
• Inventors: Konno, Mark, Mooney, Charles R.
• Primary Examiner(s): Shaver, Kevin
• Assistant Examiner(s): MARMOR II, CHARLES ALAN
• Application Number:
  US09/484,555
• Time in Patent Office: 840 Days
• Field of Search: 600/433-435, 600/504, 600/505, 600/526, 600/549, 604/246, 604/93.01, 604/523, 604/290, 374/100
• US Class Current: 600/549
• CPC Class Codes: A61B 1/012 characterised by internal passages or accessories therefor
• CPC Class Codes: A61B 1/018 for receiving instruments
• CPC Class Codes: A61B 2018/00166 Multiple lumina
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/028 by thermo-dilution

Abstract

An access device such as a catheter, or introducer, or any combination of the above is provided. Within the access device is at least one lumen, channel or instrument that carries or itself is a thermally active mass, such as infusion fluids, control wires, etc. A temperature sensor such as a thermistor is secured to the access device in order to measure the temperature of a temperature medium, typically blood; in a patient. Various insulating lumens, insulating members and mounting and extrusion configurations are provided by the invention to insulate the temperature sensor thermally from the thermal mass, which might otherwise degrade the accuracy of the temperature measurement. The invention also provides an arrangement whereby the temperature sensor is connected to an external monitor for display of the patient'"'"'s temperature.

Claims

1. A device for measuring the temperature of a temperature medium of a patient comprising:

an access device that is insertable into the patient at a location of the temperature medium, including at least one thermal mass other than the temperature medium, such at least one thermal mass being located within a thermal lumen of the access device;

a pair of ports formed in an outer wall of the access device;

a temperature sensor supported by the access device;

at least one insulating structure insulating the temperature sensor from the thermal mass; and

a flow channel formed within the access device and extending between the pair of ports wherein the temperature medium occupies the flow channel, wherein the flow channel is located between the temperature sensor and the thermal lumen, the flow channel thereby both increasing thermal contact between the temperature sensor and the temperature medium and also thermally isolating the temperature sensor further from the thermal lumen.

2. A device as defined in claim 1, wherein the temperature sensor is located externally to an outer surface of the access device.

3. A device as defined in claim 1, wherein the temperature sensor is mounted in a carrier.

4. A device as defined in claim 3, in which the access device has more than one lumen, the insulating structure is formed as a barrier within the carrier and the carrier is held in one of the lumens of the access device with the barrier extending between the temperature sensor and the thermal lumen.

5. A device as defined in claim 4, in which the carrier is removably insertable in the lumen of the access device.

6. A device as defined in claim 3, in which the carrier is removably insertable in the lumen of the access device.

7. A device as defined in claim 1, in which each insulating structure extends between the temperature sensor and each thermal lumen.

8. A device as defined in claim 1, wherein the flow channel is located between the insulating structure and the thermal lumen.

9. A device as defined in claim 1, in which the temperature sensor is attached to the access device.

10. A device as defined in claim 1, wherein the insulating structure comprises at least one interior insulating lumen formed within the access device and extending between the temperature sensor and the thermal mass.

11. A device as defined in claim 1, wherein

the access device includes a plurality of lumens;

the temperature sensor is mounted within a recess in an insulating member; and

the insulating member, together with the temperature sensor, are mounted within one of the lumens of the access device so that the insulating member extends between the temperature sensor and the thermal lumen.

12. A device as defined in claim 1, wherein the insulating structure includes an insulating material co-extruded with the access device and surrounding at least a portion of each thermal lumen.

13. A device as defined in claim 1, wherein the insulating structure includes an insulating material co-extruded with the access device and surrounding the temperature sensor.

14. A device as defined in claim 1, wherein the insulating structure is expandable to increase the distance between the temperature sensor and the thermal mass.

15. A method for measuring the body temperature of a patient comprising the following steps:

supporting a temperature sensor on an access device;

inserting the access device into a blood vessel;

introducing at least one thermal mass into the access device; and

insulating the temperature sensor from the thermal mass by providing

a pair of ports formed in an outer wall of the access device; and

a flow channel formed within the access device and extending between the pair of ports, in which a temperature medium occupies the flow channel, wherein the flow channel is located between the temperature sensor and the thermal mass.

16. A method as defined in claim 15 further providing a signal conductor from the temperature sensor to an external patient temperature monitor.

17. A method as defined in claim 15, further including the following steps:

introducing the thermal mass via a thermal lumen located within the access device;

mounting the temperature sensor in a sensor lumen within the access device; and

forming at least one additional thermally insulating structure between the temperature sensor and the thermal lumen.

18. A method as defined in claim 15, further including the following steps:

forming an insulating structure as at least one insulating lumen within the access device; and

introducing a thermally insulating material into the insulating lumen.

19. A device for measuring the temperature of a temperature medium of a patient comprising:

an access device that is insertable into the patient at a location of the temperature medium, including at least one thermal mass other than the temperature medium, such at least one thermal mass being located within a thermal lumen of the access device;

a pair of ports formed in an outer wall of the access device;

a temperature sensor supported by the access device; and

an insulating structure insulating the temperature sensor from the thermal mass,

wherein the insulating structure comprises a flow channel formed within the access device and extending between the pair of ports so that the temperature medium occupies the flow channel, the flow channel is located between the temperature sensor and the thermal lumen, the flow channel thereby both increasing thermal contact between the temperature sensor and the temperature medium and also thermally isolating the temperature sensor further from the thermal lumen.

20. A device as defined in claim 19, wherein the flow channel is a chamber located near the temperature sensor.

21. A device as defined in claim 19, wherein the flow channel is a lumen passing through any portion of the length of the access device.

22. A device as defined in claim 19, wherein the temperature sensor is positioned within an indentation in an outer wall of the access device.

23. A device as defined in claim 19, wherein the insulating structure further comprises at least one interior insulating lumen formed within the access device and extending between the temperature sensor and the thermal mass.

24. A device as defined in claim 19, wherein the insulating structure further comprises an insulating material surrounding the temperature sensor.

25. A device for measuring the temperature of a temperature medium of a patient comprising:

an access device that is insertable into the patient at a location of the temperature medium, the access device having a plurality of lumens including at least one thermal lumen with a thermal mass other than the temperature medium;

a temperature sensor supported by the access device; and

at least one insulating gap extending near the location of the temperature sensor and between the temperature sensor and the plurality of lumens to thermally isolate the temperature sensor from the thermal mass.

26. A device as defined in claim 25, wherein the temperature sensor is located within a sensor lumen of the access device.

27. A device as defined in claim 25, in which:

the access device has an opening in an outer wall; and

the temperature sensor, when in a deployed position, extends into the opening, thereby increasing thermal contact between the temperature sensor and the temperature medium and further insulating the temperature sensor from the thermal mass.

28. A device as defined in claim 27, in which:

the temperature sensor is mounted on a carrier;

ends of the carrier are secured within the access device; and

the carrier is positioned between the temperature sensor and each thermal lumen, thereby forming the insulating structure.

29. A device as defined in claim 27, in which the temperature sensor is a right-angle thermistor mounted to extend out of the opening mainly perpendicular to a central axis of the access device.

30. A device as defined in claim 27, wherein:

the temperature sensor is mounted within a carrier which protrudes as a loop out through the opening in the outer wall of the access device and ends of the carrier are secured within the access device;

the insulating gap comprises a flow channel for the temperature medium which is formed between the carrier and the access device at the position of the opening, and thus between the temperature sensor and the thermal mass; and

the temperature sensor is exposed substantially over its entire outer circumference to the temperature medium, via only the carrier.

31. A device as defined in claim 25, in which the temperature sensor is adhesively attached and the adhesive is dissolvable at body temperature, the temperature sensor thereby increasing contact with the temperature medium when in position within the patient.

32. A device as defined in claim 25, wherein:

the access device has a lumen and a sensor port; and

the temperature sensor is mounted on a distal tip of a probe which is insertable into the lumen of the access device so that the temperature sensor extends through the sensor port.

33. A device as defined in claim 25, wherein:

the insulating gap comprises a distal tip of the access device formed from an insulating material as a separate member; and

the temperature sensor is mounted within the distal tip.

34. A device as defined in claim 25, in which:

the access device has a distal tip with a lengthwise extending slit;

the temperature sensor is mounted on a first side of the distal tip;

the plurality of lumens including at least one thermal lumen carrying the thermal mass extend through a second side of the distal tip; and

the distal tip, once in a deployed position, is separated along the slit, with the first and second sides of the tip being located on either side of the slit.

35. A device as defined in claim 25, in which:

the access device is a central venous catheter;

the temperature medium is blood;

the thermal mass is an infusion fluid that is carried within one of the lumens; and

the temperature sensor is a thermistor.

36. A device as defined in claim 25, wherein the temperature sensor is located within an indentation in an outer wall of the access device.

37. A device as defined in claim 25, wherein the temperature sensor is located externally to an outer surface of the access device.

38. A device as defined in claim 25, wherein the temperature sensor is mounted in a carrier.

39. A device as defined in claim 38, wherein the carrier is removably insertable in one of the lumens of the access device.

40. A device as defined in claim 38, wherein the insulating gap is formed as a barrier within the carrier.

41. A device as defined in claim 25, wherein the insulating gap comprises a generally elongated slit extending at least along a portion of the length of the access device.

42. A device as defined in claim 25, wherein the insulating gap is shaped to surround the temperature sensor.

43. A device as defined in claim 25, wherein the insulating gap is expandable.

44. A device as defined in claim 25, wherein the temperature sensor is mounted on the access device by a dissolvable potting compound.