System And Method For Evaluating Physiological Parameter Data

• US 20090210163A1
• Filed: 02/18/2009
• Published: 08/20/2009
• Est. Priority Date: 02/19/2008
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Amundson, Scott, Ochs, James, Batchelder, Keith
• Granted Patent: US 8,275,553 B2
• Time in Patent Office: Days
• US Class Current: 702/19
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

Embodiments disclosed herein may include systems and methods for evaluating physiological parameter data. Embodiments of methods may include monitoring a patient to produce a signal comprising a sequence of numerical values for a physiological parameter over a time period, calculating an index from the signal, comparing the index to a reported index, and if the index is greater than the reported index, setting the reported index to the value of the index. Embodiments of methods may include calculating a modulation of the signal, comparing the modulation to a previous value of the modulation to identify a trend in the modulation and if the trend corresponds to an undesirable condition, using a first function to increase the reported index. Embodiments of methods may include providing an indication of a physiological status based on the reported index.

Claims

1. A method of evaluating physiological parameter data, comprising:

monitoring a patient to produce a signal comprising a sequence of numerical values for a physiological parameter over a time period;

calculating an index based at least in part upon the signal;

comparing the calculated index to a reported index, and if the calculated index is greater than the reported index, setting the reported index to the value of the calculated index;

calculating a modulation of the signal;

comparing the modulation to a previous value of the modulation of the signal to identify a trend in the modulation, and if the trend corresponds to an undesirable condition, using a first function capable of increasing the reported index; and

providing an indication of a physiological status based at least in part upon the reported index.

2. The method of claim 1, wherein the modulation comprises the difference between a maximum value of the signal and a minimum value of the signal divided by a mean value of the signal over a period of time.

3. The method of claim 1, comprising applying a second function capable of decreasing the reported index, if the trend does not correspond to an unfavorable condition.

4. The method of claim 1, wherein the first function comprises a parabolic growth function, and/or an exponential growth function.

5. The method of claim 1, comprising filtering the reported index by a third function.

6. The method of claim 5, wherein the third function comprises an infinite impulse response filter.

7. The method of claim 1, wherein the index comprises an airway instability index.

8. The method of claim 2, wherein the period of time comprises a period of time over which a qualified pattern is occurring.

9. A medical device, comprising:

a microprocessor configured to process a signal associated with at least one physiological parameter of a patient; and

a memory configured to store machine readable instructions which, if executed, are capable of causing the microprocessor to;

calculate an index from the signal;

compare the calculated index to a reported index, and if the calculated index is greater than the reported index, set the reported index to the value of the calculated index;

calculate a modulation of the numerical signal;

compare the modulation to a previous value of the modulation to identify a trend in the modulation, and if the trend corresponds to an undesirable condition, increase the reported index using a first function; and

provide an indication of a physiological status based on the reported index.

10. The medical device of claim 9, wherein the modulation comprises the difference between a maximum value of the numerical signal and a minimum value of the numerical signal divided by a mean value of the numerical signal over a period of time.

11. The medical device of claim 9, wherein the contents of the memory comprises machine readable instructions which, if executed, are capable of causing the microprocessor to apply a second function to decrease the reported index, if the trend does not correspond to an unfavorable condition.

12. The medical device of claim 9, comprising a network interface unit capable of sending information comprising the numerical signal, and/or the reported index, to a device located on a local area network.

13. The medical device of claim 9, wherein the machine readable instructions, if executed, are capable of causing the microprocessor to filter the reported index by a third function.

14. The medical device of claim 9, wherein the first function comprises a parabolic growth function, and/or an exponential growth function.

15. The medical device of claim 13, wherein the third function comprises an infinite impulse response filter.

16. The medical device of claim 9, wherein the index comprises an airway instability index.

17. A method of evaluating physiological parameter data, comprising:

monitoring a patient to produce a signal comprising a sequence of numerical values for a physiological parameter over a time period;

detecting potential reciprocations by detecting potential reciprocation peaks and nadirs in the sequence of numerical values;

determining whether the potential reciprocations are qualified by comparing metrics of the potential reciprocations with a set of limits and performing a linear qualification function;

tracking a number of qualified reciprocations identified within a window of time and calculating an index when the number of qualified reciprocations identified within the window of time reaches or surpasses a limit;

comparing the calculated index to a reported index, and if the calculated index is greater than the reported index, setting the reported index to the value of the calculated index; and

providing an indication of a physiological status based at least in part upon the reported index.

18. The method of claim 17, comprising:

calculating a modulation of the signal; and

comparing the modulation to a previous value of the modulation to identify a trend in the modulation and if the trend corresponds to an undesirable condition, using a first function capable of increasing the reported index.

19. The method of claim 17, comprising calculating the index based at least in part upon an average magnitude of all qualified reciprocations within a time period relative to the current time, an average of a fixed number of the highest reciprocation peaks of qualified reciprocations within the time period, and/or an average of a fixed number of the highest reciprocation nadirs of qualified reciprocations within the time period, and/or combinations thereof.

20. The method of claim 17, wherein the window of time may be defined based on historical values.