CATHETER SYSTEM

• US 3,822,695 A
• Filed: 12/27/1972
• Issued: 07/09/1974
• Est. Priority Date: 12/29/1971
• Status: Expired due to Term

• Current Assignee: Syuichi Takayama
• Original Assignee: Syuichi Takayama
• Inventors: Takayama, Syuichi
• Primary Examiner(s): Howell, Kyle L.
• Application Number:
  US05/318,994
• Time in Patent Office: 559 Days
• Field of Search: 128/2L,2A,2G,2.5D,2.5G,2.5R 356/41
• US Class Current: 600/325
• CPC Class Codes: A61B 5/02154 by optical transmission
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence

Abstract

A catheter system in which an optical fiber bundle has one end divided into first, second and third sections and the other end so shaped as to be covered with an elastic film which is elastically deflectable under an external force and permit insertion into the blood vessel. When light including light signals of 8,050 A, 6,600 A and 5,300 A is transmitted from said first section to said other end, the light signals of 8,050 A and 6,600 A are reflected from the blood to said second section through said elastic film and the light signal of 5,300 A is reflected from said elastic film to said third section. A first detector associated with said second section alternately detects the light signals of 8,050 A and 6,600 A and produces first and second corresponding electrical signals as a serial output which is corrected by an electrical signal corresponding to the light signal of 5,300 A and generated from a second detector to provide an electrical signal required for obtaining information on the percentage content of oxygen contained in the blood. Since the elastic film may elastically deflect with variation in the blood pressure to vary the amount of the light of 5,300 A reflected from the elastic film, information on the blood pressure may be obtained from the second detector.

Claims

1. A catheter system for simultaneously measuring in vivo the oxygen content and pressure of blood comprising:

an optical fiber bundle adapted to be inserted into a blood vessel, said bundle being divided into three sections, the first optically connected to a source emitting light signals of 8,050 A, 6,600 A, and 5,300 A, the second for receiving inflected light signals of 8,050 A and 6,600 A, and the third for receiving reflected light signals of 5,300 A;

an elastic, deformable film spaced from and covering the end of said bundle opposing the light source and capable of transmitting light signals of 8,050 A and 6,600 A but reflecting signals of 5,300 A;

a first detecting means associated with said second fiber bundle section for alternately receiving, detecting and converting into corresponding electrical signals, light signals of 8,050 A and 6,600 A from said second fiber bundle section reflected from the blood and including an error component reflected from said elastic film;

a second detecting means associated with said third fiber bundle section for receiving, detecting and converting into corresponding electrical signals, light signals of 5,300 A from said third fiber bundle section reflected from said elastic film;

correcting means connected with the output electrical signals from each of the two aforesaid detecting means for subtracting from the electrical signals generated by the reflected light of 8,050 A and 6,600 A the electrical signals generated by the reflected light of 5,300 A which corresponds to the error component reflected from said elastic film at 8,050 A and 6,600 A;

first means for receiving signals from said correcting means and converting the same into signals representing the percentage content of oxygen contained in the blood; and

second means connected to the second detecting means for providing electrical signals corresponding to those reflected from the elastic film at 5,300 A representing blood pressure.

2. A catheter system according to claim 1 wherein said elastic film is made of a material selected from the group consisting of polyester, polyurethane and silicone resin and has a reflection surface on its inner surface which passes light signals of 8,050 A and 6,600 A and reflects a light signal of 5,300 A. 3 A catheter system according to claim 2 wherein said reflection surface is formed of a thin film of metal compound selected from the group consisting of magnesium fluoride, selenium dioxide and sodium fluoroaluminate.

4. A catheter system according to claim 1 wherein said first detecting means includes a motor-driven, rotatable disc having a first filter which can pass only the light signal of 6,600 A and a first phototube disposed opposite the end face of said second fiber bundle section and said disc being disposed there between with said filters in optical alignment with said phototube upon rotation of the disc.

5. A catheter system according to claim 1 wherein said correcting means includes first and second factor multipliers means for adjusting a level of the signal produced by reflection at 5,300 A in proportiion to an error component in the signals corresponding to light signals of 8,050 A and 6,600 A reflected from said elastic film and contained in the output from said first detecting means and a substractor means for substracting the outputs of said first and second factor multiplier means from the output of said first detecting means.

6. A catheter system according to claim 1 wherein said first means for receiving signals comprises a first gate means for deriving the electrical signals corresponding to the 8,050 A light signal and a second gate means for deriving the electrical signal corresponding to the 6,600 A light signal from the output of said correcting means and a calculator means for producing therefrom a signal representing the percentage content of oxygen contained in the blood;

and said second means connected to the second detecting means comprises an operational amplifier means for amplifying the output of said second detecting unit, level shifter means for shifting the output of said operational amplifier means, and an inverter means for inverting the output from said level shifter to provide a signal representing the blood pressure.