System and method for facilitating observation of monitored physiologic data

• US 9,993,208 B2
• Filed: 09/08/2015
• Issued: 06/12/2018
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Batchelder, Keith, Amundson, Scott, Brecht, Mark
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): TOTH, KAREN E
• Application Number:
  US14/848,173
• Publication Number:
  US 20160058396A1
• Time in Patent Office: 1,008 Days
• 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 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/7235 Details of waveform analysis A61B5/349 takes precedence
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: A61B 5/7445 Display arrangements, e.g. multiple display units
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B

Abstract

Present embodiments are directed to a system and method capable of detecting and graphically indicating physiologic patterns in patient data. For example, present embodiments may include a monitoring system that includes a monitor capable of receiving input relating to patient physiological parameters and storing historical data related to the parameters. Additionally, the monitoring system may include a screen capable of displaying the historical data corresponding to the patient physiological parameters. Further, the monitoring system may include a pattern detection feature capable of analyzing the historical data to detect a physiologic pattern in a segment of the historical data and capable of initiating a graphical indication of the segment on the screen when the physiologic pattern is present in the segment.

Claims

1. A pulse oximeter, comprising:

an input for receiving a photoplethysmograph (PPG) signal from a pulse oximetry sensor, wherein the pulse oximetry sensor detects light attenuated by a patient;

a non-transitory computer-readable medium comprising;

computer program instructions recorded thereon for causing the pulse oximeter to;

(a) process the PPG signal to generate oxygen saturation data,

(b) compute a mean of the oxygen saturation data and a standard deviation of the oxygen saturation data in a first window of time;

(c) calculate an upper band and a lower band based on a computed value of the mean of the oxygen saturation data and the standard deviation of the oxygen saturation data;

(d) identify peaks in the oxygen saturation data based on the current upper band and the lower band;

(e) analyze the identified peaks to detect reciprocations in the oxygen saturation data, each reciprocation defined by a fall peak, a nadir, and a rise peak,

(f) qualify each of the detected reciprocations based on qualification criteria,

(g) determine a duration of each qualified reciprocation,

(h) maintain a count of qualified reciprocations,

repeat steps b-h using oxygen saturation data in a subsequent window of time, wherein the size of the subsequent window of time is determined based on durations of a predetermined number of previous reciprocations,

and determine an occurrence of a clustering state indicative of a presence of ventilatory instability based on the count;

and a display for displaying a ventilatory instability notification while the clustering state is determined to be occurring.

2. The pulse oximeter of claim 1, wherein the non-transitory computer-readable medium further comprises computer program instructions recorded thereon for causing the pulse oximeter to determine a scoring metric associated with consecutive qualified reciprocations.

3. The pulse oximeter of claim 2, wherein the non-transitory computer-readable medium further comprises computer program instructions recorded thereon for causing the pulse oximeter to determine the scoring metric while the clustering state is determined to be occurring.

4. The pulse oximeter of claim 2, wherein the non-transitory computer-readable medium further comprises computer program instructions recorded thereon for causing the pulse oximeter to trigger an alarm when the scoring metric reaches a threshold.

5. The pulse oximeter of claim 1, wherein the count of qualified reciprocations is maintained over a time period.

6. The pulse oximeter of claim 1, wherein the count of qualified reciprocations is maintained over a time period determined based on a length of a qualified reciprocation.

7. The pulse oximeter of claim 1, wherein the qualification criteria comprise a fall magnitude of the detected reciprocations.

8. The pulse oximeter of claim 1, wherein the qualification criteria comprise a slope ratio of the detected reciprocations.

9. The pulse oximeter of claim 1, wherein the qualification criteria comprise a path length ratio of the detected reciprocations.

10. The pulse oximeter of claim 1, wherein the qualification criteria comprise:

fall magnitude of the detected reciprocations, slope ratio of the detected reciprocations, and path length ratio of the detected reciprocations.

11. The pulse oximeter of claim 1, wherein the qualification criteria comprise a linear qualification function.

12. A pulse oximetry system, comprising:

an input for receiving a photoplethysmograph (PPG) signal from a pulse oximetry sensor, wherein the pulse oximetry sensor detects light attenuated by a patient;

circuitry configured to;

(a) determine oxygen saturation of the patient based on the PPG signal;

(b) compute a mean of the oxygen saturation and a standard deviation of the oxygen saturation in first window of time;

(c) calculate an upper band and a lower band based on a computed value of the mean of the oxygen saturation and the standard deviation of the oxygen saturation;

(d) identify peaks in the oxygen saturation data based on the current upper band and the lower band;

(e) detect reciprocations based on the identified peaks, each reciprocation defined by a fall peak, a nadir, and a rise peak;

(f) apply qualification criteria to each of the detected reciprocations;

(g) determine a duration of each qualified reciprocation;

repeat steps (b)-(g) using oxygen saturation data in a subsequent window, wherein the size of the subsequent window is determined based on durations of a predetermined number of previous reciprocations; and

determine an occurrence of a clustering state when at least two consecutive reciprocations are qualified;

and a display for displaying a ventilatory instability notification while the clustering state is determined to be occurring.

13. The pulse oximetry system of claim 12, wherein the circuitry is further configured to determine a scoring metric associated with consecutive qualified reciprocations.

14. The pulse oximetry system of claim 13, wherein the circuitry is further configured to determine the scoring metric while the clustering state is determined to be occurring.

15. The pulse oximetry system of claim 13, wherein the circuitry is further configured to trigger an alarm when the scoring metric reaches a threshold.

16. The pulse oximetry system of claim 12, wherein the circuitry is further configured to maintain a count of qualified reciprocations over a time period.

17. The pulse oximetry system of claim 12, wherein the circuitry is further configured to maintain a count of qualified reciprocations over a time period determined based on a length of a qualified reciprocation.

18. The pulse oximetry system of claim 12, wherein the qualification criteria comprise a fall magnitude of the detected reciprocations.

19. The pulse oximetry system of claim 12, wherein the qualification criteria comprise a slope ratio of the detected reciprocations.

20. The pulse oximetry system of claim 12, wherein the qualification criteria comprise a path length ratio of the detected reciprocations.

21. The pulse oximetry system of claim 12, wherein the qualification criteria comprise:

a fall magnitude of the detected reciprocations, a slope ratio of the detected reciprocations, and a path length ratio of the detected reciprocations.

22. The pulse oximetry system of claim 12, wherein the qualification criteria comprise a linear qualification function.

23. A pulse oximeter, comprising:

an input for receiving a photoplethysmograph (PPG) signal from a pulse oximetry sensor, wherein the pulse oximetry sensor detects light attenuated by a patient;

means for detecting a presence of ventilatory instability, wherein the means for detecting the presence of ventilatory instability comprise a non-transitory computer-readable medium comprising;

computer program instructions recorded thereon for causing the pulse oximeter to;

(a) process the PPG signal to generate oxygen saturation data,

(b) compute a mean of the oxygen saturation data and a standard deviation of the oxygen saturation data in a first window of time;

(c) calculate an upper band and a lower band based on a computed value of the mean of the oxygen saturation data and the standard deviation of the oxygen saturation data;

(d) identify peaks in the oxygen saturation data based on the current upper band and the lower band;

(e) analyze the identified peaks to detect reciprocations in the oxygen saturation data, each reciprocation defined by a fall peak, a nadir, and a rise peak,

(f) qualify each of the detected reciprocations based on qualification criteria,

(g) determine a duration of each qualified reciprocation,

(h) maintain a count of qualified reciprocations,

repeat steps (b)-(h) using oxygen saturation data in a subsequent window, wherein the size of the subsequent window is determined based on durations of a predetermined number of previous reciprocations,

and determine an occurrence of a clustering state indicative of the presence of ventilatory instability based on the count;

and a display for displaying a ventilatory instability notification when the presence of ventilatory instability is detected.

24. A method for determining ventilatory instability by a pulse oximeter, comprising:

receiving, using an input of the pulse oximeter, a photoplethysmograph (PPG) signal from a pulse oximetry sensor, wherein the pulse oximetry sensor detects light attenuated by a patient;

determining, using the pulse oximeter, oxygen saturation data of the patient based on the PPG signal;

(a) computing, using the pulse oximeter, a mean of the oxygen saturation data and a standard deviation of the oxygen saturation data in a first window of time;

(b) calculating, using the pulse oximeter, an upper band and a lower band based on a computed value of the mean of the oxygen saturation data and the standard deviation of the oxygen saturation data;

(c) identifying, using the pulse oximeter, peaks in the oxygen saturation data based on the current upper band and the lower band;

(d) detecting, using the pulse oximeter, reciprocations based on the identified peaks, each reciprocation defined by a fall peak, a nadir, and a rise peak;

(e) applying, using the pulse oximeter, qualification criteria to each of the detected reciprocations;

(f) determining, using the pulse oximeter, a duration of each qualified reciprocation,

(g) determining, using the pulse oximeter, an occurrence of a clustering state when at least two consecutive reciprocations are qualified;

repeating, using the pulse oximeter, steps a-g using oxygen saturation data in a subsequent window, wherein the size of the subsequent window is determined based on durations of a predetermined number of previous reciprocations;

and displaying, using a display of the pulse oximeter, a ventilatory instability notification when the clustering state is determined to be occurring.