CARDIOVASCULAR CATHETER FOR THERMAL DILUTION MEASUREMENT

• US 3,726,269 A
• Filed: 11/24/1971
• Issued: 04/10/1973
• Est. Priority Date: 11/24/1971
• Status: Expired due to Term

• Current Assignee: Wilton W. Webster Jr
• Original Assignee: Wilton W. Webster Jr
• Inventors: Webster, Wilton W. Jr.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/201,791
• Time in Patent Office: 503 Days
• Field of Search: 128/2.5D,2.5E,2.5F,2.5R,348-351 73/204,194M
• US Class Current: 600/526
• CPC Class Codes: A61B 5/028 by thermo-dilution
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61M 25/04 in the body, e.g. expansible A61M25/10, A61M16/0488 take precedence

Abstract

A catheter for use in measuring blood massflow or ventricular volume by thermal dilution techniques is of the double lumen type in which the inner lumen is of very small diameter and is essentially flaccid. The inner lumen extends for the major portion of its length along a coolant liquid flow passage formed in a larger, more robust outer lumen of the catheter, but terminates in an anterior terminal portion outside the outer lumen adjacent the anterior end of the catheter. Apertures are formed through the outer lumen from the coolant flow passage. A dilution temperature sensor, such as a thermistor, is carried by the external anterior portion of the inner lumen in such relation to the apertures that the sensor is spaced from the apertures along a blood vessel, for example, regardless of whether the anterior terminal portion of the outer lumen trails back along the catheter in retrograde flow cases or forwardly toward the anterior end of the catheter in antegrade flow cases. The posterior end of the catheter carries means for injecting coolant liquid into the outer lumen and for connecting the temperature sensor to appropriate readout equipment, such as Wheatstone bridge circuit.

Claims

1. A catheter comprising an elongate slender flexible tube, a slender flexible and flaccid probe disposed within the tube through a substantial portion of the length of the tube, the probe having an outer diameter sufficiently less than the inner diameter of the tube to provide a liquid flow passage within the tube around the probe to an anterior end thereof adjacent an anterior end of the tube, means coupled to the posterior end of the tube for injecting a coolant liquid into the passage, coolant liquid discharge means from the passage adjacent the anterior end of the passage, the probe extending through the tube adjacent the coolant liquid discharge means to a terminal portion thereof disposed externalLy of the tube, and an electrical temperature sensing device mounted to the terminal portion of the probe for sensing the temperature of liquid flowing therepast.

2. A catheter according to claim 1 including a second temperature sensing device operatively disposed in the passage for sensing the temperature of liquid flowing therepast.

3. A catheter according to claim 2 wherein the second temperature sensing device is disposed in the passage adjacent the coolant liquid discharge means.

4. A catheter according to claim 2 wherein the second temperature sensing device is carried by the probe.

5. A catheter according to claim 1 wherein the probe terminal portion extends to an anterior end disposed externally of the tube and movable relative to the tube.

6. A catheter according to claim 1 wherein the probe terminal portion is movable relative to the tube externally of the tube.

7. A catheter according to claim 1 wherein the temperature sensing device is disposed at the anterior end of the probe.

8. A catheter according to claim 1 wherein the temperature sensing device is disposed intermediate the elongate extent of the probe terminal portion.

9. A catheter according to claim 1 including a second electrical temperature sensing device mounted to the probe terminal portion and spaced therealong from the first sensing device.

10. A catheter according to claim 1 wherein the spacing of the sensing device along the probe terminal portion from the location at which the probe extends through the tube is greater than the spacing of said location along the tube from the coolant liquid discharge means.

11. A catheter according to claim 10 wherein said location is spaced posteriorly along the tube from the coolant liquid discharge means.

12. A catheter according to claim 1 wherein the sensing device is a thermistor.

13. A catheter according to claim 1 including conductor means connected to the sensing device and extending posteriorly thereof within the probe to a posterior end of the probe disposed externally of the tube.

14. A catheter according to claim 1 wherein the tube and passage anterior ends are spaced along the tube and the tube therebetween defines a duct to the tube anterior end, the duct having a diameter which is substantially reduced from the diameter of the passage.

15. A catheter according to claim 14 wherein the duct has a diameter which corresponds to the diameter of a guidewire for the catheter.

16. A catheter according to claim 14 wherein the tube anteriorly from the anterior end of the passage is arranged normally to define a loop configuration which is deformable to substantially coaxial alignment with the adjacent portions of the tube.

17. A catheter according to claim 1 wherein the probe is fixedly connected to the tube proximate the location at which the probe extends through the tube to the probe terminal portion.

18. A flowmeter catheter comprising an elongate slender flexible tube, a slender flexible and flaccid probe disposed within the tube through a substantial portion of the length of the tube, the probe having an outer diameter sufficiently less than the inner diameter of the tube to provide a liquid flow passage within the tube around the probe to an anterior end thereof adjacent an anterior end of the tube, means coupled to the posterior end of the tube for injecting a coolant liquid into the passage, coolant liquid discharge means from the passage adjacent the anterior end of the passage, the probe extending through the tube posteriorly of but adjacent the coolant liquid discharge means to a terminal portion thereof disposed externally of the tube, a first thermistor mounted to the end of the terminal portion of the probe for sensing the temperature of liquid flowing therepast, the spacing of the first thermistor along the probe from the location at which the probe extends through the tube being greater than the spacing of said location along the tube from the coolant liquid discharge means, a second Thermistor carried by the probe within the tube adjacent the coolant liquid discharge means for sensing the temperature of liquid flowing therepast in the passage, and conductor means extending from the thermistors within the probe to the posterior end of the probe externally of the tube.

19. A flowmeter catheter comprising an elongate slender flexible tube, a slender flexible and flaccid probe disposed within the tube through a substantial portion of the length of the tube, the probe having an outer diameter sufficiently less than the inner diameter of the tube to provide a liquid flow passage within the tube around the probe to an anterior end thereof adjacent an anterior end of the tube, means coupled to the posterior end of the tube for injecting a coolant liquid into the passage, coolant liquid discharge means from the passage adjacent the anterior end of the passage, the probe extending through the tube posteriorly of but adjacent the coolant liquid discharge means to a terminal portion thereof disposed externally of the tube, spaced first and second thermistors mounted to the terminal portion of the probe intermediate the length of the terminal portion for sensing the temperature of liquid flowing therepast, the spacing of the first and second thermistors along the probe from the location at which the probe extends through the tube being greater than the spacing of said location from the coolant liquid discharge means, a third thermistor carried by the probe within the tube adjacent the coolant liquid discharge means for sensing the temperature of liquid flowing therepast in the passage, and conductor means extending from the thermistors within the probe to the posterior end of the probe externally of the tube.