Blood pressure measuring apparatus

• US 3,926,179 A
• Filed: 04/03/1974
• Issued: 12/16/1975
• Est. Priority Date: 04/03/1974
• Status: Expired due to Term

• Current Assignee: Dennis E. Bahr, Jeffrey C. Petzke
• Original Assignee: Dennis E. Bahr, Jeffrey C. Petzke
• Inventors: Bahr, Dennis E., Petzke, Jeffrey C.
• Primary Examiner(s): Howell, Kyle L.
• Application Number:
  US05/457,485
• Time in Patent Office: 622 Days
• Field of Search: 128/2.5N,2.5M,2.5A,2.5E,2.5P,2.5T,2.6F,2T 73/80
• 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 7/00 Instruments for auscultation

Abstract

This invention provides apparatus for accurately measuring and continuously monitoring blood pressure. The apparatus comprises a blood pressure probe adapted to engage a body member such as one arm of the patient. The probe includes a pressure applying member for engaging the surface of the body member, over an artery which is near the surface. For example, the pressure applying member may be located over the radial artery in the wrist of the patient'"'"''"'"'s arm. The probe also includes pressure exerting means, such as a solenoid, for pressing the pressure applying member against the surface of the body member, so as to produce partial flattening of the artery. The pressure applying member includes a pressure sensor adapted to engage the surface of the body member over the artery for sensing the blood pressure pulses in the artery. The sensor includes a transducer for producing electrical signals corresponding to the blood pressure pulses. The apparatus includes control means for operating the pressure exerting means to maximize the electrical signals corresponding to the pulse pressure. For example, a feedback circuit may be provided to energize the solenoid to such an extent as to maximize the pulse pressure signals. Generally, the signals will be maximized when the artery is flattened approximately halfway. The true or corrected waveform of the blood pressure signals may be derived and displayed on an oscilloscope for continuously monitoring the blood pressure variations. Means may also be provided for deriving and indicating the systolic and diastolic blood pressure values, and also the pulse pressure. The blood pressure measuring apparatus is highly accurate, continuous in operation, and noninvasive, in that it is not necessary to invade the artery. Moreover, the function of the artery is not impaired, since the device is nonocclusive. The blood pressure probe, together with the supporting apparatus, is called a tonometer.

Claims

1. Apparatus for measuring the blood pressure in an artery near the surface of a body member, comprising a blood pressure probe having a housing for engaging the body member, said probe including a pressure applying member movably mounted in said housing for engaging the surface of the body member over said artery, power operated pressure exerting means on said probe for pressing said pressure applying member against the surface of said body member to produce a degree of flattening of said artery, a sensor in said pressure applying member for engaging the surface of said body member over said artery to sense the pressure pulses in said artery, said sensor including a transducer for producing electrical signals corresponding to said pressure pulses, and control means having an input circuit for receiving said electrical signals and power output regulating means connected to said pressure exerting means and responsive to said electrical signals for operating said pressure exerting means in a variable manner to maximize said electrical signals corresponding to said pressure pulses.

2. Apparatus according to claim 1, in which said pressure applying member is formed with an opening, said sensor being mounted in said opening for responding to the pressure pulses in said artery.

3. Apparatus according to claim 1, in which said pressure exerting means comprises a solenoid for exerting a variable amount of force on said pressure applying member.

4. Apparatus according to claim 3, in which said control means comprises a feedback circuit for receiving said electrical signals and energizing said solenoid to maximize such electrical signals.

5. Apparatus according to claim 1, in which said control means includes a feedback circuit for receiving said electrical signals and energizing said power operated pressure exerting means to maximize said signals.

6. Apparatus according to claim 5, including measuring means for indicating the values of said electrical signals.

7. Apparatus according to claim 1, including measuring means for indicating the values of said electrical signals.

8. Apparatus according to claim 1, said housing having an opening therein, said pressure applying member being disposed in said opening and being movable therein for engagement with the surface of said body member.

9. Apparatus according to claim 1, in which said pressure exerting means is connected between said housing and said pressure applying member for exerting force upon said pressure applying member for transmission to the body member.

10. Apparatus according to claim 1, in which said pressure exerting means is mounted on said housing and is connected to said pressure applying member for exerting pressure thereon.

11. Apparatus according to claim 1, in which said power operated pressure exerting means comprises a solenoid for exerting variable pressure upon said pressure applying member for transmission to the body member.