Multi-level averaging scheme for acquiring hemodynamic data

• US 7,766,826 B2
• Filed: 11/26/2003
• Issued: 08/03/2010
• Est. Priority Date: 11/26/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Lee, Brian B., Bennett, Tommy D.
• Primary Examiner(s): Johnson, III; Henry M
• Assistant Examiner(s): Rajan; Kai
• Application Number:
  US10/723,364
• Publication Number:
  US 20050113647A1
• Time in Patent Office: 2,442 Days
• Field of Search: 600/300, 600/481, 600483-486, 600508-526, 600500-504, 600/301, 607 23- 26
• US Class Current: 600/300
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/335 using integrated circuit memory devices

Abstract

A system and method for storing and processing physiological data in a medical recording device that allows continuous data collection and storage of such data in multiple time-resolved levels are provided. The method includes: sampling one or more physiological signals at a selected sampling rate; deriving physiological parameter values from the sampled signal; storing the parameter values as they are determined in a temporary memory buffer for a predetermined storage interval; determining a statistical aspect of the stored parameter values upon expiration of the storage interval; and writing the statistical aspect to a long-term memory buffer. A number of long-term memory buffers may be designated for storing a statistical aspect of a physiological parameter at uniquely different time resolutions. The resolution of each long-term memory buffer is determined by the storage interval defined for an associated temporary memory buffer, which stores parameter values from which statistical aspects are computed.

Claims

1. A method performed by a processor for storing and processing physiological mechanical data in an implantable medical recording device, the method comprising:

sampling one or more physiological signals at a selected sampling rate;

deriving physiological parameter values from the sampled signal to obtain parameterized signal data at a rate lower than the selected sampling rate of the physiological signal;

storing the parameter values as they are determined in a temporary memory buffer for a predetermined storage interval;

determining a statistical aspect of the stored parameter values in the temporary buffer upon expiration of the storage interval; and

writing the statistical aspect as it is determined for a plurality of the predetermined storage intervals to a long-term memory buffer, the long-term memory buffer storing the statistical aspects for a long-term storage interval, the long-term memory buffer thereby storing statistical aspects having a temporal resolution of the parameter values corresponding to the predetermined storage interval of the temporary memory buffer, further comprising;

allocating the temporary memory buffer into at least two different temporary memory buffers and programming a unique storage interval to each of the two different temporary memory buffers.

2. A method according to claim 1, further comprising allocating the long-term memory buffer into at least two different long-term memory buffers each having a unique temporal resolution, wherein the unique temporal resolution of each long-term memory buffer is determined by the predetermined storage interval of a respective one of the temporary memory buffers.

3. A method according to claim 2, wherein the at least two long-term memory buffers comprise digital memory buffers.

4. A method according to claim 2, wherein the unique temporal resolution comprises at least a one of:

a coarse resolution having a relatively low temporal resolution, a medium resolution having a higher temporal resolution than said course resolution, and a fine resolution having the highest temporal resolution compared to said coarse resolution and said medium resolution.

5. A method according to claim 4, wherein upon expiration of a predetermined storage interval or upon exceeding available memory storage of a given long-term storage buffer the following step is performed:

transferring a set of data comprising the statistical aspect or the stored parameter values from one of said fine resolution and said medium resolution to said coarse resolution and from said fine resolution to said medium resolution.

6. A method according to claim 4, further comprising:

allocating available memory for the stored parameters based at least in part upon a respective temporal resolution assigned to each of the stored parameters, wherein said respective temporal resolution comprise said coarse resolution, said medium resolution, said fine resolution.

7. A method according to claim 6, wherein the allocating further comprises automatic partitioning of available memory based upon the number of stored parameters or the temporal resolution of the stored parameters.