EP0208520B1
Expired / Lapsed
EP
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Oscillometric blood pressure monitor employing non uniform pressure decrementing steps
Assignee: Ethicon Inc
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Filing: 1986-07-04
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Granted: 1992-04-15
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Expires: 2006-07-04
Abstract
Abstract The deflation of the inflatable and deflatable cuff worn by a subject during automatic sphygmomanometric measurement is accomplished in unequal size decrements and principally in larger steps than 7 Torr. Each step after detection of the initial oscillations is determined in the first instance by reference to a look-up table or en equation as a function of prevailing cuff pressure. This Base Step dimension is augmented by a factor proportional to the last oscillation amplitude, the factor being increased after detection of the maximum oscillation amplitude. A valve mechanism with at least two different effective orifice sizes is used for deflation, the smaller size effective orifice being used first, to maintain control over the decrement step rate while holding the time for decrement within a predetermined limit of 8 mSec. per Torr, i. e., maintaining the rate above 125 Torr per second. The valve mechanism can consist of two valves with unequal orifice size, or it can consist of two equal orifice size valves to be used singly for providing the effective smaller orifice, or in parallel to provide the effective larger orifice. Alternatively a single variable orifice valve can be used.
Inventors
- 👤 Maynard Ramsey Iii
- 👤 Richard Medero
- 👤 Rush W. Hood, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 03:13
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/02; A61B5/021; A61B5/022; A61B5/02225; A61B5/02108; A61B5/02116
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
178 words
Automated sphygmomanometric apparatus comprising in combination: a) an inflatable and deflatable pressure cuff (101); b) inflating means operatively coupled to said cuff for selectably supplying a gaseous medium under pressure to said cuff to inflate and pressurize said cuff; c) cuff pressure sensing means (105) coupled to said cuff for sensing cuff pressure and any oscillations in cuff pressure; d) deflate valve means (102) coupled to said cuff for selectably releasing said gaseous medium from said cuff in successive decrements; and e) processing means (108) responsively coupled to said cuff pressure sensing means, for blood pressure related measurements; characterised in that there is provided (f) control means (108) responsive to pressure sensed by said cuff pressure sensing means for automatically establishing, for a next subsequent cuff pressure decrement, as a function of the prevailing cuff pressure, at least one of (i) cuff pressure decrement size and (ii) the rate of release of said gaseous medium, said control means in combination with said deflate valve means being constructed and arranged to deflate said cuff in non-uniform pressure decrementing steps.
Claim 2
Dependent Claim
109 words
Automated sphygmomanometric apparatus according to claim 1, characterised in that said deflate valve means comprise means for providing at least two different pressure dependent flow rates, one faster and one slower for any given cuff pressure, for releasing said gaseous medium from said cuff, and said control means comprises selector means for initiating release of said gaseous medium from said cuff using said deflate valve means that provides the slower flow rate (103) and continuing to use said slower-flow-rate-providing deflate valve means (103) until the deflation rate has slowed to a predetermined value whereupon said selector means uses said faster-flow-rate-providing deflate valve means (104), or both valve means together.
Claim 3
Dependent Claim
27 words
Automated sphygmomanometric apparatus according to claim 2, wherein said control means includes rate determining means for ascertaining the rate of deflation prevailing during each successive decrement step.
Claim 4
Dependent Claim
79 words
Automated sphygmomanometric apparatus according to claim 2 or claim 3, characterized in that said deflate valve means comprises a first valve (103) with a given size orifice, and a second valve (104) with an orifice larger than said given size orifice; and said selector means is constructed and arranged to commence a deflation cycle using said first valve, and to switch to said second valve if the deflation rate with said first valve is slower than said predetermined value.
Claim 5
Dependent Claim
50 words
Automated sphygmomanometric apparatus according to claim 4, characterised in that said selector means is further constructed and arranged to switch to parallel use of said first and second valves whenever said flow rate using said second valve becomes slower than said predetermined value, until said cuff has attained desired deflation.
Claim 6
Dependent Claim
73 words
Automated sphygmomanometric apparatus according to claim 2 or claim 3 characterised in that said deflate valve means comprises two valves each with the same size orifice; and said selector means is constructed and arranged to commence a deflation cycle using only one of said deflate valves, and to switch to parallel use of both of said two valves if the deflation rate with said one deflate valve is slower than said predetermined value.
Claim 7
Dependent Claim
59 words
Automated sphygmomanometric apparatus according to any one of claims 1 to 6, characterised in that said control means comprises deflate step determining means for causing substantially equal successive pressure decrements after initiation of a cuff deflation procedure and before an arterial pressure oscillation is detected by said processing means and causing increased decrement steps after said oscillation is detected.
Claim 8
Dependent Claim
71 words
Automated sphygmomanometric apparatus according to claim 7, characterised in that said step determining means is constructed and arranged to cause said increased decrement steps in accordance with the relationship: Decrement Step = Base Step + y (x/a) wherein Base Step is a predetermined function of prevailing cuff pressure, "x" is a quantity proportional to the last detected oscillation amplitude, "y" is equal to one or two, and "a" is a constant.
Claim 9
Dependent Claim
29 words
Automated sphygmomanometric apparatus according to claim 8, characterised in that "y" is equal to one during a measurement cycle until a maximum amplitude oscillation has been detected and identified.
Claim 10
Dependent Claim
48 words
Automated sphygmomanometric apparatus according to any one of claims 1 to 6, characterised in that said control means comprises deflate step determining means coupled to said cuff pressure sensing means for causing said pressure decrementing steps to vary in magnitude as a function of the prevailing cuff pressure.
Claim 11
Dependent Claim
48 words
Automated sphygmomanometric apparatus according to claim 10, characterised in that said pressure decrementing steps are determined, at least in part, so as to satisfy the equation: Decrementing Step = k*CP where "CP" = cuff pressure and "k" is a constant having a value on the order of 0.1.
Claim 12
Dependent Claim
58 words
Automated sphygmomanometric apparatus according to claim 10 characterized in that said pressure decrementing steps are determined, at least in part, so as to satisfy the equation: Decrementing Step = k₁ + k₂*CP where "CP" = cuff pressure in Pa and "k₁" and "k₂" are constants having respective values on the order of 533 Pa (4 Torr) and 0.05.
Claim 13
Dependent Claim
41 words
Automated sphygmomanometric apparatus according to any one of claims 7 to 12, characterised in that said deflate step determining means is adapted to cause at least some of said pressure decrementing steps to be in excess of 933 Pa (7 Torr).
Claim 14
Dependent Claim
30 words
Automated sphygmomanometric apparatus according to any one of claims 1 to 13, further including processing means responsively coupled to said cuff pressure sensing means for providing blood pressure related measurements.
References Cited (Backward Citations)
US4360029A
Cited
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