Non invasive measurement of blood pressure

• US 20040097815A1
• Filed: 10/28/2003
• Published: 05/20/2004
• Est. Priority Date: 05/14/2001
• Status: Active Grant

• Current Assignee: Microlife Intellectual Property GmbH
• Original Assignee: Microlife Intellectual Property GmbH
• Inventors: Forstner, Klaus
• Granted Patent: US 6,929,610 B2
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence

Abstract

By a method to measure the blood pressure of a patient, a series of measurements for the diastolic, the systolic blood pressure and for the pulse rate are made. The results are analysed in order to determine, and to display whether the patient is properly settled to a rest condition, and whether the patients blood pressure variation is found as being normal. Further it is investigated. whether there are high measurement result alterations due to artefacts. Highly altered results are excluded. If the results are sufficiently similar, an average of the result is made. If the results are not sufficiently similar, but still below pre-defined alteration limits, a weighted average is applied to the systolic and the diastolic blood pressure.

Claims

1. A method for non-invasively measuring the blood pressure of a patient, comprising the steps of

a) measuring the diastolic and the systolic blood pressure value and the pulse rate of the patient, preferably by the oscillometric method;

b) repeating step a) at least once thereby generating a series of consecutive measurement results (S1, S2, S3, D1, D2, D3, P1, P2, P3) of the systolic and diastolic blood pressure and of the pulse rate;

c) automatically analysing said series of consecutive results for determining the validity of said results by verifying whether a first condition (i.) is fulfilled, whereby said first condition (i.) is fulfilled if results of the systolic blood pressure are continuously decreasing and if the results of the diastolic blood pressure are continuously decreasing or increasing and if the results of the pulse rate are continously decreasing.

2. A method according to claim 1, wherein in step c), a variation index (VI) of the diastolic blood pressure, the systolic blood pressure and the pulse rate according to the following formula is calculated:

3. A method according to one of the claims 1 or 2, comprising the further steps of

verifying whether a third condition (iii.) is fulfilled, whereby the third condition (iii.)is fulfilled when the differences between subsequent measurement results of the systolic and of the diastolic blood pressure measurement are below a predetermined or predeterminable similarity limit and

of verifying whether a fourth condition (iv.) is fulfilled, whereby the fourth condition (iv.) is fulfilled when the differences between subsequent measurement results of the systolic and the diastolic blood pressure are above a predetermined or predeterminable alteration limit.

4. A method according to one of the claims 1 to 3, wherein if the first condition (i.) is met,

a signal is generated advising the user to repeat the measurement or

an additional measurement is automatically initiated after a predetermined period of time, and/or

a signal is generated, said signal indicating that the user has not been properly settled to a rest condition in the course of the measurement.

5. A method according to claim 2, wherein if the second condition (ii.) is met, a message is displayed to the user..

6. A method according to claim 3, wherein

if the third condition (iii.) is met, an arithmetic average of the measurement results of the diastolic blood pressure (D1, D2, D3) and of the systolic blood pressure (S1, S2, S3) and of the pulse frequency (P1, P2, P3) is calculated and displayed and

wherein if the fourth condition (iv.),is met, results above the alteration limit are disregarded and a new measurement of the systolic and of the diastolic blood pressure is made and wherein

if the third condition (iii.) is not met, a weighted average of the systolic of the diastolic blood pressure measurement results and the pulse frequency result is calculated,

7. A device for non-invasively measuring the blood pressure of a patient, especially for carrying out a method according to one of the claims 1 to 6, the device comprising

means for non-invasively measuring the systolic and the diastolic blood pressure and pulse rate of a patient;

means for storing a series of consecutive measurement results of the systolic blood pressure, the diastolic blood pressure and the heart rate;

means for analysing the series of measurement results of the diastolic, the systolic blood pressure and the pulse rate,

wherein the means for analysing are adapted to determine whether the results of the systolic blood pressure are continuously decreasing and the results of the diastolic blood pressure are continuously increasing or decreasing and the results of the pulse rate are continuously decreasing.

8. A device according to claim 7, wherein the means for analysing are adapted to calculate a variation index for each of the systolic blood pressure, the diastolic blood pressure and the pulse rate according the following formula:

9. A device according to one of the claims 7 or 8, wherein the means for analysing are further adapted to verify whether the differences between consecutive results of the systolic blood pressure and of the diastolic blood pressure are above a predetermined or predeterminable alteration limit or below a predetermined or predeterminable similarity limit.

10. A device according to one of the claims 7 to 9, wherein the device further comprises means for forming an average of measurement results of the systolic blood pressure and the diastolic blood pressure and means for forming a weighted average of the measurement results of the systolic blood pressure and of the diastolic blood pressure.