Method and apparatus for determining pulse rate

• US 4,790,326 A
• Filed: 04/01/1987
• Issued: 12/13/1988
• Est. Priority Date: 04/01/1987
• Status: Expired due to Term

• Current Assignee: Colin Electronics Co., Ltd.
• Original Assignee: Nippon Colin Company Limited
• Inventors: Wenzel, Dennis J., Fox, William C., Mather, Bruce C., Peel, Harry H.
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US07/033,407
• Time in Patent Office: 622 Days
• Field of Search: 128/687-690, 128/702, 128/706, 128/714, 364/417
• US Class Current: 600/502
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/6831 Straps, bands or harnesses

Abstract

A method for determining the pulse rate of a person. The method of the present invention is implemented in two phases. The first phase involes the determination of pulse intervals and the second phase provides an indication of the pulse rate based on the data produced during the first phase. The first phase is implemented by an algorithm which produces a pulse distribution profile from an array of pulses obtained from an appropriate transducer. In the second phase of the measurement, the distribution is searched to locate the region of maximum density. The pulse rate within the maximally dense region are then averaged to determine pulse rate. The pulse rate detection method of the present invention eliminates a significant number of erroneous pulse signals before calculation of pulse rate, thus providing a more accurate indication of the true pulse rate. The processing algorithm used in the preferred embodiment is based on an integer distribution the measurement can be obtained with a minimum amount of system memory and processor time.

Claims

1. A method for determining the pulse rate of a person, comprising the steps of:

obtaining a set of data corresponding to pulsatile variations in a blood vessel of said person;

processing said data to obtain a pulse distribution profile of said pulse rates, said step of processing said data comprising the steps of forming an array of time position indices corresponding to the said data points and calculating pulse rates for each of said time position indices;

locating the region of maximum density in said pulse distribution profile; and

determining said person'"'"'s pulse rate from said region of maximum density in said pulse distribution profile.

2. The method according to claim 1, said step of locating said region of maximum pulse density comprising the step of sampling said pulse distribution profile with a moving window summing algorithm, said moving window having a predetermined width of between 5 and 20 indices.

3. The method according to claim 2, said step of correlating said region of maximum pulse density with said person'"'"'s pulse rate further comprising the step of averaging the pulse rates in said region of maximum density.

4. A method of determining the pulse rate of a person, comprising the steps of:

obtaining a set of data points corresponding to pulsatile variations detected by a transducer in pressure communication with a blood vessel of said person, said data set containing actual pulse data and spurious pulse data;

processing said data set to obtain an array of time position indices corresponding to said pulsatile variations;

calculating pulse rates for each of said time position indices;

forming a pulse distribution profile of said pulse rates;

locating the region of maximum density in said pulse distribution profile, said spurious pulse data being substantially eliminated from said region of maximum density; and

computing a weighted average of the pulse rates in said region of maximum density to obtain an indication of the person'"'"'s pulse rate.

5. The method according to claim 4, said step of locating said region of maximum pulse density comprising the step of sampling said pulse distribution profile with a moving window summing algorithm, said moving window having a predetermined width.

6. The method according to claim 5, said window having a width of between 5 and 20 indices.

7. The method according to claim 6, said window having a width of nine indices.