Method of automated blood pressure detection

• US 4,543,962 A
• Filed: 07/09/1984
• Issued: 10/01/1985
• Est. Priority Date: 07/09/1984
• Status: Expired due to Term

• Current Assignee: Critikon Co. LLC
• Original Assignee: Critikon, Inc.
• Inventors: Medero, Richard, Apple, Howard P., Ramsey, Maynard III, Hood, Rush W.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Sykes, Angela D.
• Application Number:
  US06/628,861
• Time in Patent Office: 449 Days
• Field of Search: 128/672, 128/677, 128/680-683
• US Class Current: 600/495
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/02225 using the oscillometric method

Abstract

A pressure cuff on the patient is inflated to a predetermined pressure above systolic, and then is deflated incrementally. At each decrement, oscillatory complexes are detected, and respective peaks are compared and evaluated as "true" complexes if they are within certain size matching criteria. After such "true" complexes are identified at a predetermined number of levels (e.g. 2 or 3), only a single complex is investigated at subsequent levels, provided specified size and timing criteria are met.

Claims

1. In an automatic oscillometric blood pressure system measurement method utilizing successive decremental arterial counterpressures to measure blood pressure complexes through detection of counterpressure oscillation, an improved detection method comprising:

(a) establishing a predetermined counterpressure above systolic pressure;

(b) decrementing said counterpressure in predetermined decrements to different pressure levels, each such pressure level being maintained for at least a predetermined duration;

(c) sensing more than one complex at a first predetermined number of pressure levels, and comparing successive complex peak amplitudes at each such level to detect onset of true blood pressure complexes; and

(d) after said detection of true complexes at a predetermined number of successive such pressure levels, commencing sensing but one complex at each level.

2. A method as described in claim 1 wherein said step of sensing but one complex per level includes comparing each such complex at each such level with predetermined validity criteria based on immediately prior complexes.

3. A method as described in claim 2, wherein said validity criteria include amplitude criteria based on the amplitude of the peak height of previous complexes, and timing window criteria based on heart rate as determined from the rate of occurrence of previous complexes.

4. A method as described in claim 1, wherein counterpressure is established by inflation pressure of a cuff on the subject.