METHOD AND APPARATUS FOR CONTINUOUSLY MONITORING BLOOD PRESSURE

• US 3,880,145 A
• Filed: 10/02/1972
• Issued: 04/29/1975
• Est. Priority Date: 10/02/1972
• Status: Expired due to Term

• Current Assignee: Edward F. Blick
• Original Assignee: Edward F. Blick
• Inventors: Blick, Edward F.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/293,991
• Time in Patent Office: 939 Days
• Field of Search: 128/2.5E,2.5N,2.5P,2.5R,2.5S,2.5T,2.5V,2.6E,2.6R,2R,2T 73/419,420,408
• US Class Current: 600/485
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02444 Details of sensor A61B5/02427 takes precedence
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: G01L 9/0002 using variations in ohmic resistance G01L9/0051 takes precedence

Abstract

An electro-mechanical force sensing transducer for use with suitable receiving and recording means for measuring intraarterial blood pressure which includes a housing having a bore formed therethrough with a force sensing head disposed in the lower portion of the bore for engaging the surface of the skin over a superficial artery to sense blood pressure variations. A positioning member is threadedly secured in the upper portion of the bore and a compression spring is disposed between the positioning member and the force sensing head for urging the force sensing head into contact with the surface of the skin. The force sensing head includes a conventional strain gage enclosed therein with electrical conduit means extending therefrom for connection to the receiving and recording means. Another aspect of the present invention is a transducer assembly including the force sensing transducer carried in a supporting frame and attachable to a patient by means of a strap secured to the supporting frame. In another form the transducer assembly includes two force sensing transducers. In still another form the force sensing transducer assembly includes three force sensing transducers. In yet another form the transducer assembly includes four force sensing transducers. Also disclosed are methods for continuously monitoring blood pressure utilizing the transducer assemblies disclosed.

Claims

1. A non-invasive method of providing a continuous direct indication of the arterial blood pressure of a patient at a continuously unoccluded superficial artery without the necessity of detecting Korotkov sounds, comprising the steps of:

positioning a first force sensing transducer on the skin surface of the patient directly over and not occluding the continuously unoccluded superficial artery;

positioning a second force sensing transducer on the skin surface of the patient alongside, but not over, the superficial artery;

directly sensing, with the first force sensing transducer, physical arterial geometric distorions of the superficial artery indicative of blood pressure variations within the superficial artery in addition to force components not originating as a result of arterial blood pressure variations;

directly sensing, with the second force sensing transducer, said force components not originating as a result of said arterial blood pressure variations;

sending a continuous first signal from the first force sensing transducer, with the first force signal including a component indicative of the pressure of blood in the superficial artery and a component representing said force components not orginating as a result of said arterial blood pressure variations;

sending a continuous second signal from the second force sensing transducer, the second signal including a component indicative of said force components not originating as a result of said arterial blood pressure variations;

receiving the continuous first signal from the first force sensing transducer;

receiving the continuous second signal from the second force sensing transducer;

continuously subtracting the second signal from the first signal thereby cancelling the components indicative of force components not originating as a result of said arterial blood pressure variations; and

utilizing the remaining component indicative of the pressure of blood in the artery obtained from continuously subtracting the second signal from the first signal to provide a continuous indication of arterial blood pressure.

2. A method of continuously monitoring the arterial blood pressure of a patient comprising the steps of:

positioning a first force sensing transducer on the skin surface of the patient directly over a superficial artery;

positioning a second force sensing transducer on the skin surface of the patient over one edge portion of a superficial artery;

positioning a third force sensing transducer on the skin surface of the patient over the opposite edge portion of the superficial artery;

receiving a continuous first signal from the first force sensing transducer;

receiving a continuous second signal from the second force sensing transducer;

receiving a continuous third signal from the third force sensing transducer;

continuously summing the first, second and third signals;

continuously dividing the sum of the first, second and third signals by three And;

utilizing the results obtained from continuously dividing the sum of the first, second and third signals by three to provide an indication of arterial blood pressure.

3. The method of continuously monitoring the arterial blood pressure of a patient as defined in the claim 2 characterized further to include the additional steps of:

positioning a fourth force sensing transducer on the skin surface of the patient a small distance from the superficial artery;

receiving a continuous fourth signal from the fourth force sensing transducer;

continuously subtracting the fourth signal from the resulting signal obtained by continuously dividing the sum of the first, second and third signals by three; and

utilizing the results of continuously subtracting the fourth signal from the resulting signal obtained by continuously dividing the sum of the first, second and third signals by three to provide indication of arterial blood pressure.