Carotid thermodilution catheter

• US 4,240,441 A
• Filed: 10/10/1978
• Issued: 12/23/1980
• Est. Priority Date: 10/10/1978
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Khalil, Hassan H.
• Primary Examiner(s): Howell, Kyle L.
• Application Number:
  US05/950,196
• Time in Patent Office: 805 Days
• Field of Search: 128/670, 128/692, 128/713, 128/642, 128/700, 73/204
• US Class Current: 600/505
• CPC Class Codes: A61B 5/028 by thermo-dilution
• CPC Class Codes: A61M 25/005 with embedded materials for reinforcement, e.g. wires, coils, braids

Abstract

A thermodilution catheter having a proximal high frequency heating coil of fine wires, heat measuring thermocouples, and a distal resistance thermometer, all wound externally on a catheter for measuring arterial blood flow. The device also incorporates electrodes for electrocardiogram tracing.

Claims

1. In a bioelectric measuring apparatus for insertion within an internal carotid artery of a living organism, including in combination, an elongated, flexible body, an electrical heater mounted thereon, and a temperature sensing device also mounted on said catheter body, the improvement comprising:

temperature transducing means mounted on said catheter body for sensing the temperature rise of said catheter body produced by said electrical heater; and

wherein said temperature sensing device and said electrical heater include wire windings having dimensions to facilitate compact placement within said organism and to achieve a predetermined surface area to blood volume flow ratio of from about 0.08 mm² /ml/min. to about 0.42 mm² /ml/min.

2. An improved bioelectric measuring apparatus for insertion within a living organism according to claim 1 wherein said electrical heater wire is bifilarly wound.

3. An improved bioelectric measuring apparatus for insertion within a living organism according to claim 1 further comprising:

conducting means, mounted on said catheter body, for electrical contact with said living organism.

4. An improved bioelectric measuring apparatus for insertion within a living organism according to claim 3 wherein said conducting means comprises one or more electrodes.

5. An improved bioelectric measuring apparatus for insertion within a living organism according to claim 4 wherein said electrodes comprise bare platinum wire electrodes.

6. An improved bioelectric measuring apparatus for insertion within a living organism according to claim 1 wherein said temperature transducing means comprises;

a first thermocouple positioned on said catheter body along said electrical heater wire winding;

a reference thermocouple positioned on said catheter body in series with said first thermocouple and proximal to said electric heater wire winding.

7. An improved bioelectric measuring apparatus for insertion within a living organism according to claim 6 wherein said thermocouples are copper constantan thermocouples.

8. An improved bioelectric measuring apparatus for insertion within a living organism according to claim 1 wherein said temperature sensing wire winding comprises 99.99% pure platinum wires.