Portable blood pressure recorder

• US 4,252,127 A
• Filed: 06/19/1979
• Issued: 02/24/1981
• Est. Priority Date: 06/19/1979
• Status: Expired due to Term

• Current Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Original Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Inventors: Gemelke, Ronnie L.
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Jaworski, Francis J.
• Application Number:
  US06/050,135
• Time in Patent Office: 616 Days
• Field of Search: 128/679-683, 128/710, 128/900, 346/33 ME
• US Class Current: 600/493
• CPC Class Codes: A61B 5/02208 using the Korotkoff method
• CPC Class Codes: Y10S 128/90 Blood pressure recorder

Abstract

A portable blood pressure recorder device for an ambulatory subject having an inflatable occluding cuff, a pump for inflating the cuff, a sensor for detecting Korotkoff sounds, a transducer for detecting pressure in the cuff, a variable voltage reference and signal circuitry system for encoding a pressure signal from the transducer into pressure segments, a recording system for combining the Korotkoff sounds with the encoded pressure segments, circuitry for activating and deactivating components of the device, and a data retrieval system for interpreting recorded data.

Claims

1. A portable blood pressure recorder device for an ambulatory subject comprising:

an inflatable occluding cuff;

pump means for inflating said cuff;

sensor means for detecting Korotkoff sounds in an artery occluded by said cuff;

transducer means for detecting pressure in said cuff;

variable voltage reference means for encoding a pressure signal from said transducer means into pressure segments having upper and lower level limits;

recording means for combining said Korotkoff sounds with said encoded pressure signal and processing the combined signal;

switching circuitry means for setting the initial level of said variable voltage reference means and for activating and deactivating the signal means, the pumping means, and the recording means;

signal circuitry means for comparing and summing the said signal from the transducer means and the signal from the variable voltage reference means to develop encoded pressure segments, said level of the variable voltage reference means being reset for the next lower pressure segment when the output of the transducer means exceeds the magnitude of the upper limit level and said level being subsequently reset to the next lower segment each time the output of the transducer means reaches the magnitude of said level until the lowest level is reached thereby deactivating the signal circuitry means and recording means;

and decoder data retrieval means interconnected to said recording means for interpreting recorded data.

2. The device of claim 1 wherein said pump means includes a small orifice for pressure deflation.

3. The device of claim 1 wherein said sensor means includes a crystal microphone, a buffer amplifier, and noise-reduction means for reducing noise occurring between measured heartbeats.

4. The device of claim 3 wherein said noise-reduction means includes filtering means for eliminating direct current pressure signal from the output signal of said pressure transducer, means for identifying heartbeat induced pressure pulses, and means for transmitting a signal only when the heartbeat pulse is present.

5. The device of claim 1 wherein said variable voltage reference includes means for setting upper and lower level limits for said pressure segments, means for changing levels, and means for converting a digital signal to an analog signal.

6. The device of claim 1 wherein said recording means includes a summing amplifier, a voltage-to-frequency converter, and a tape recorder.

7. The device of claim 1 wherein said decoder data retrieval means includes comparator means, rectifying means, a frequency-to-voltage converter, filtering means for said recorded data, and a two-channel recorder.