Non-invasive continuous blood pressure monitoring system

• US 5,303,711 A
• Filed: 07/09/1991
• Issued: 04/19/1994
• Est. Priority Date: 07/09/1991
• Status: Expired due to Fees

• Current Assignee: Sciarra, Michael J.
• Original Assignee: Sciarra, Michael J.
• Inventors: Sciarra, Michael J.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): NASSER, ROBERT L
• Application Number:
  US07/727,074
• Time in Patent Office: 1,015 Days
• Field of Search: 128/677, 128/680-686, 364/413.03
• US Class Current: 600/493
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers

Abstract

Apparatus for the continuous non-invasive monitoring of blood is disclosed which includes an inflatable cuff, transducers for detecting blood volume changes in the blood by detecting changes in pressure in the cuff, and a central processing unit which converts the detected blood volume changes to a measurement of blood pressure and a CRT display for displaying the pressures in a readable format.

Claims

1. Apparatus for the continuous non-invasive monitoring of blood pressure comprising, an inflatable cuff adapted to surround a limb of a patient, transducer means for detecting pressure in the cuff and producing separate A.C. and D.C. signals respectively representing a) peaks and troughs of cuff pressure and b) static pressure in the cuff;

means for initially inflating the cuff to a pressure sufficient to occlude blood flow in the limb, means for detecting systolic and diastolic blood pressure points of the patient;

means for calculating mean blood pressure of the patient based on the detected systolic and diastolic pressures;

means for reducing the pressure in the cuff to a predetermined pressure lower than diastolic occlusion pressure, means for assigning to the DC signal from the transducer means produced by said lower predetermined pressure the calculated mean blood pressure of the patient and means for monitoring the D.C. signal produced while the pressure in the cuff remains lower than said diastolic occlusion pressure to produce an output reading of the patient'"'"'s blood pressure.

2. Apparatus for the continuous non-invasive monitoring of blood pressure comprising an inflatable cuff adapted to surround a limb of a patient, means for initially inflating said cuff to a pressure sufficient to occlude blood flow in said limb;

means for detecting systolic and diastolic blood pressure points of the patient and for sensing separation between the systolic and diastolic pressures;

means for calculating a mean blood pressure of the patient as a function of the detected systolic and diastolic pressures;

means for reducing the pressure in the cuff to a predetermined pressure lower than diastolic occlusion pressure;

means for producing an A.C. signal and a D.C. signal repectively representing a) the peaks and troughs of cuff pressure and b) the mean pressure in the cuff following the reduction of pressure in said cuff to said predetermined pressure;

means for determining the separation of the peaks and troughs of said A.C. signal;

means for comparing said separation of the peaks and troughs to said separation between the systolic and diastolic pressures and means for utilizing the comparison and the D.C. signal to produce an indication of the blood pressure of the patient.

3. Apparatus for the continuous non-invasive monitoring of blood pressure comprising an inflatable cuff adapted to surround a limb of a patient;

means for initially inflating the cuff to a pressure sufficient to occlude blood pressure points of the patient;

means for detecting systolic and diastolic pressures of the patient and for calculating mean blood pressure as a function thereof;

controllable valve means opened to reduce the pressure in the cuff to a predetermined pressure lower than diastolic occlusion pressure and subsequently closed to permit the cuff pressure to vary as the patient'"'"'s pressure varies;

means for producing a D.C. signal representing the mean pressure in the cuff following the reduction of pressure in said cuff to said predetermined pressure;

means for assigning the calculated mean blood pressure to said D.C. signal when the pressure in the cuff has been reduced to said predetermined pressure; and

means for monitoring said D.C. signal as an indication of the patient'"'"'s blood pressure after the pressure in the cuff has been reduced to said predetermined pressure and said valve means remains closed.

4. The apparatus of claim 3, further comprising means for storing the monitored D.C. signal;

means for sensing when the monitored D.C. signal changes from its initial value by more than a predetermined amount;

means responsive to said sensing means for opening said valve means to restore the pressure in the cuff to said predetermined pressure; and

means for inhibiting the monitored D.C. signal from being stored while the pressure in the cuff is restored.

5. The apparatus of claim 4, further including means for producing an A.C. signal representing peaks and troughs of cuff pressure;

means for determining the separation between said peaks and troughs after said valve means is closed and said predetermined pressure is reached; and

means for monitoring changes in said separation to indicate changes in the systolic and diastolic pressures of the patient.

6. Apparatus for the non-invasive monitoring of blood pressure comprising an inflatable cuff adapted to surround a limb of a patient, transducer means for detecting pressure in the cuff and producing A.C. signals representing peaks and troughs of cuff pressure;

means for initially inflating the cuff to a pressure sufficient to occlude blood flow in the limb and for thereafter reducing the pressure in the cuff to a predetermined pressure lower than a diastolic occlusion pressure;

means for determining a separation between the peaks and troughs of said A.C. signal following the reduction of pressure in said cuff to said predetermined pressure;

means for monitoring changes in said separation between the peaks and troughs; and

means for indicating changes in said separation.