Systems and methods for monitoring heart rate and blood pressure correlation

• US 8,216,136 B2
• Filed: 03/05/2009
• Issued: 07/10/2012
• Est. Priority Date: 03/05/2009
• Status: Active Grant

• Current Assignee: Nellcor Puritan Bennett Ireland
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Addison, Paul Stanley, Watson, James, Sethi, Rakesh
• Primary Examiner(s): Gedeon, Brian T
• Application Number:
  US12/398,826
• Publication Number:
  US 20100228102A1
• Time in Patent Office: 1,223 Days
• Field of Search: 600/485, 600/509, 600/513, 600/301
• US Class Current: 600/301
• 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 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

Systems and methods are provided for monitoring a correlation between heart rate and blood pressure in a patient. When a characteristic of the correlation exceeds a threshold, a patient status indicator signal is sent to a monitoring device. In some embodiments, the patient status indicator signal indicates a particular medical condition or alerts a care provider to a change in status. In some embodiments, the heart rate signal is used to improve a blood pressure estimate generated by a different signal. In some embodiments, the heart rate, blood pressure and correlation signals are used in a predictive mathematical model to estimate patient status or outcome.

Claims

1. A method for monitoring patient status with a processor comprising:

receiving an electronic signal indicative of a patient'"'"'s heart rate;

receiving an electronic signal indicative of a patient'"'"'s blood pressure;

calculating a correlation of the two received signals;

determining whether the correlation is negative;

generating a patient status indicator signal in response to determining that the correlation is negative; and

indicating, with an output device, a patient status in response to receiving the patient status indicator signal.

2. The method of claim 1 wherein indicating a patient status comprises at least one of displaying the correlation characteristic on a screen, displaying a message associated with the patient status indicator signal, displaying a color associated with the patient status indicator signal, displaying a graphic associated with the patient status indicator signal, and producing a sound associated with the patient status indicator signal.

3. The method of claim 1, wherein generating a patient status indicator signal comprises querying a lookup table to retrieve a value for a patient status, wherein the lookup table is stored in an electronic memory device communicably coupled to the processor.

4. The method of claim 1 further comprising calculating a current blood pressure based at least in part on the received electronic signal indicative of a patient'"'"'s heart rate.

5. The method of claim 1 further comprising predicting at least one of a patient outcome and current status using a computational model based at least in part on the two received signals.

6. A system for monitoring a patient'"'"'s status comprising:

at least one memory device;

a display device, capable of indicating a patient status in response to receiving a patient status indicator signal; and

a processor, communicably coupled to the at least one memory device and the display device and capable of receiving at least one input signal, the processor configured to;

calculate a heart rate waveform based on at least an input signal indicative of a patient'"'"'s heart rate;

calculate a blood pressure waveform based at least an input signal indicative of a patient'"'"'s blood pressure;

store a patient status indicator value in the at least one memory device;

calculate a correlation of the two calculated waveforms;

for each of at least one patient condition;

identify a rate of change, associated with the condition, of the correlation;

determine whether the rate of change exceeds a threshold associated with the condition, wherein the threshold is stored in one of the at least one memory device;

when the rate of change exceeds the threshold, update the stored patient status indicator value to represent the condition; and

generate a patient status indicator signal based on at least the stored patient status indicator value.

7. The system of claim 6 wherein indicating a patient status in response to receiving a patient status indicator signal with the display device comprises at least one of displaying the correlation characteristic on a screen, displaying a message associated with the patient status indicator signal, displaying a color associated with the patient status indicator signal, displaying a graphic associated with the patient status indicator signal, and producing a sound associated with the patient status indicator signal.

8. The system of claim 6, wherein generating a patient status indicator signal comprises querying a lookup table to retrieve a value for a patient status, wherein the lookup table is stored in the at least one memory device.

9. The system of claim 6, wherein the processor is further configured to calculate a current blood pressure based at least in part on the electronic signal indicative of a patient'"'"'s heart rate.

10. The system of claim 6, wherein the processor is further configured to predict at least one of a patient outcome and current status using a computational model based at least in part on the electronic signals.

11. Computer-readable medium for use in monitoring patient status, the computer-readable medium having computer program instructions recorded thereon for:

receiving an electronic signal indicative of a patient'"'"'s heart rate;

receiving an electronic signal indicative of a patient'"'"'s blood pressure;

calculating a correlation of the two received signals;

determining whether the correlation is negative;

generating a patient status indicator signal in response to determining that the correlation is negative; and

directing an output device to indicate a patient status in response to receiving the patient status indicator signal.

12. The computer-readable medium of claim 11 wherein generating a patient status indicator signal comprises querying a lookup table, stored in an electronic memory device, to retrieve a value for a patient status.

13. A method for monitoring patient status with a processor comprising:

receiving an electronic signal indicative of a patient'"'"'s heart rate;

receiving an electronic signal indicative of a patient'"'"'s blood pressure;

calculating a correlation of the two received signals;

determining whether a rate of change of the correlation exceeds a threshold;

generating a patient status indicator signal in response to determining whether the characteristic of that the rate of change of the correlation exceeds the threshold; and

indicating, with an output device, a patient status in response to receiving the patient status indicator signal.

14. The method of claim 13 wherein indicating a patient status comprises at least one of displaying the correlation characteristic on a screen, displaying a message associated with the patient status indicator signal, displaying a color associated with the patient status indicator signal, displaying a graphic associated with the patient status indicator signal, and producing a sound associated with the patient status indicator signal.

15. The method of claim 13, wherein generating a patient status indicator signal comprises querying a lookup table to retrieve a value for a patient status, wherein the lookup table is stored in an electronic memory device communicably coupled to the processor.

16. The method of claim 13 further comprising calculating a current blood pressure based at least in part on the received electronic signal indicative of a patient'"'"'s heart rate.

17. The method of claim 13 further comprising predicting at least one of a patient outcome and current status using a computational model based at least in part on the two received signals.

18. A system for monitoring a patient'"'"'s status comprising:

at least one memory device;

a display device, capable of indicating a patient status in response to receiving a patient status indicator signal; and

a processor, communicably coupled to the at least one memory device and the display device and capable of receiving at least one input signal, the processor configured to;

calculate a heart rate waveform based on at least an input signal indicative of a patient'"'"'s heart rate;

calculate a blood pressure waveform based at least an input signal indicative of a patient'"'"'s blood pressure;

store a patient status indicator value in the at least one memory device;

calculate a correlation of the two calculated waveforms;

determine whether the correlation is negative;

in response to determining that the correlation is negative, change the stored patient status indicator value; and

generate a patient status indicator signal based on at least the stored patient status indicator value.

19. The system of claim 18 wherein indicating a patient status in response to receiving a patient status indicator signal with the display device comprises at least one of displaying the correlation characteristic on a screen, displaying a message associated with the patient status indicator signal, displaying a color associated with the patient status indicator signal, displaying a graphic associated with the patient status indicator signal, and producing a sound associated with the patient status indicator signal.

20. The system of claim 18, wherein generating a patient status indicator signal comprises querying a lookup table to retrieve a value for a patient status, wherein the lookup table is stored in the at least one memory device.

21. The system of claim 18, wherein the processor is further configured to calculate a current blood pressure based at least in part on the electronic signal indicative of a patient'"'"'s heart rate.

22. The system of claim 18, wherein the processor is further configured to predict at least one of a patient outcome and current status using a computational model based at least in part on the electronic signals.

23. Computer-readable medium for use in monitoring patient status, the computer-readable medium having computer program instructions recorded thereon for:

receiving an electronic signal indicative of a patient'"'"'s heart rate;

receiving an electronic signal indicative of a patient'"'"'s blood pressure;

calculating a correlation of the two received signals;

determining whether a rate of change of the correlation exceeds a threshold;

generating a patient status indicator signal in response to determining that the rate of change of the correlation exceeds a threshold; and

directing an output device to indicate a patient status in response to receiving the patient status indicator signal.

24. The computer-readable medium of claim 23 wherein generating a patient status indicator signal comprises querying a lookup table, stored in an electronic memory device, to retrieve a value for a patient status.