METHOD AND DEVICE FOR MONITORING THE INTEGRITY OF A CONNECTION SYSTEM

• US 20130204542A1
• Filed: 12/22/2010
• Published: 08/08/2013
• Est. Priority Date: 12/28/2009
• Status: Active Grant

• Current Assignee: Gambro Lundia AB (Baxter International Inc.)
• Original Assignee: Gambro Lundia AB (Baxter International Inc.)
• Inventors: Olde, Bo, Solem, Kristian
• Granted Patent: US 9,632,018 B2
• Time in Patent Office: Days
• US Class Current: 702/35
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/226 comprising means for identifying the connector, e.g. to prevent incorrect connection to socket
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3653 Interfaces between patient blood circulation and extra-corporal blood circuit
• CPC Class Codes: A61M 1/3656 Monitoring patency or flow at connection sites; Detecting disconnections
• CPC Class Codes: A61M 1/3659 Cannulae pertaining to extracorporeal circulation
• CPC Class Codes: A61M 2205/13 with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2230/04 Heartbeat characteristics, e.g. ECG, blood pressure modulation
• CPC Class Codes: A61M 2230/06 Heartbeat rate only
• CPC Class Codes: A61M 5/16859 Evaluation of pressure response, e.g. to an applied pulse
• CPC Class Codes: G01N 19/08 Detecting presence of flaws or irregularities

Abstract

A device is configured to monitor the integrity of a connection system between first and second fluid containing systems comprising first and second pulse generators. A pressure sensor is arranged in the first fluid containing system to detect first pulses originating from the first pulse generator and second pulses originating from the second pulse generator. The device operates a monitoring method, by generating (42) a time-dependent pressure signal based on measurement data obtained from the pressure sensor such that the pressure signal contains a sequence of apparent pulses. The apparent pulses represent a superposition of the second pulses on the first pulses when the connection system (C) is intact. The device processes (44) the pressure signal to calculate a parameter value based on a pulse feature of at least one of the apparent pulses in the pressure signal. The parameter value represents a disturbance caused by the superposition of the second pulses on the first pulses, and may be given as a measure of statistical dispersion, pulse-to-pulse symmetry, or first pulse similarity. The device determines (45) the integrity of the connection system based at least partly on the parameter value. The first fluid containing system may be an extracorporeal blood circuit, and the second fluid containing system may be a human or animal subject.

Claims

1. A method for monitoring the integrity of a connection system between first and second fluid containing systems, wherein the first fluid containing system comprises a first pulse generator, and the second fluid containing system comprises a second pulse generator, and wherein at least one pressure sensor is arranged in the first fluid containing system to detect first pulses originating from the first pulse generator and second pulses originating from the second pulse generator, said method comprising:

generating a time-dependent monitoring signal based on measurement data obtained from said at least one pressure sensor such that the monitoring signal contains a sequence of apparent pulses, said apparent pulses representing a superposition of the second pulses on the first pulses when the connection system is intact;

processing the monitoring signal to calculate a parameter value based on a pulse feature of at least one of the apparent pulses in the monitoring signal, the parameter value representing a disturbance caused by the superposition of the second pulses on the first pulses; and

determining the integrity of the connection system based at least partly on the parameter value.

2. The method of claim 1, wherein each pulse feature is indicative of at least one of a magnitude, a timing and a shape of one of the apparent pulses.

3. The method of claim 1, wherein the parameter value is calculated as a symmetry measure between at least two of the apparent pulses.

4. The method of claim 1, wherein processing the monitoring signal further comprises comparing at least one pair of pulse features obtained from a set of apparent pulses.

5. The method of claim 4, wherein the set of apparent pulses is selected to yield a known relation between said at least one pair of pulse features when the connection system is compromised.

6. The method of claim 1, wherein the pulse feature comprises shape-indicative data and calculating the parameter value comprises:

obtaining reference data, and comparing the shape-indicative data to the reference data.

7. The method of claim 6, wherein the shape-indicative data comprises signal values in the monitoring signal, and the reference data comprises a temporal reference profile.

8. The method of claim 7, wherein said comparing comprises:

obtaining timing infoiniation indicative of the timing of the first pulses in the monitoring signal, and using the timing information to align the signal values in the monitoring signal with the temporal reference profile.

9. The method of claim 6, wherein the parameter value is indicative of a similarity or a deviation between the shape-indicative data and the reference data.

10. The method of claim 6, wherein the reference data is representative of the shape of at least one first pulse.

11. The method of claim 6, wherein the shape-indicative data is extracted by an analysis of the frequency content of the monitoring signal, and wherein the reference data is at least representative of an amplitude spectrum.

12. The method of claim 11, wherein the shape-indicative data is further extracted by an analysis of the phase content of the monitoring signal, and wherein the reference data is further representative of a phase spectrum.

13. The method of claim 6, further comprising obtaining a current value of one or more system parameters of the first fluid containing system, and obtaining the reference data as a function of the current value.

14. The method of claim 13, wherein said one or more system parameters is indicative of the rate of first pulses in the first fluid containing system.

15. The method of claim 6, wherein obtaining the reference data comprises:

deriving, based on timing information indicative of the timing of the first pulses in the monitoring signal, a set of signal segments in the monitoring signal; and

aligning and combining the signal segments, based on the timing information, to generate the reference data as an average signal profile.

16. The method of claim 1, wherein processing the monitoring signal further comprises identifying each pulse feature based on timing information which is indicative of the timing of the first pulses in the monitoring signal.

17. The method of claim 1, wherein processing the monitoring signal further comprises identifying each pulse feature based on an identification of given signal features in the apparent pulses.

18. The method of claim 1, wherein processing the monitoring signal comprises:

generating an envelope for a sequence of apparent pulses in the monitoring signal, and identifying said pulse feature in the envelope.

19. The method of claim 18, wherein generating the envelope comprises:

determining a magnitude value for each apparent pulse, and generating the envelope as a sequence of the magnitude values.

20. The method of claim 1, wherein processing the monitoring signal comprises calculating the parameter value as a statistical dispersion measure of the pulse features of a plurality of apparent pulses.

21. The method of claim 1, wherein processing the monitoring signal comprises:

generating a frequency domain representation of the monitoring signal, and calculating the parameter value based on the frequency domain representation.

22. The method of claim 1, wherein determining the integrity comprises:

calculating a statistical measure of a plurality of parameter values, and evaluating the statistical measure, each parameter value being calculated by processing a respective time segment in the monitoring signal.

23. The method of claim 1, wherein processing the monitoring signal comprises:

calculating the parameter value as a statistical dispersion measure of signal values in the monitoring signal.

24. The method of claim 1, wherein the first fluid containing system is an extracorporeal blood processing system, wherein the second fluid containing system is a vascular system of a subject, and wherein the connection system comprises an access device configured to connect to a blood vessel access of the vascular system.

25. The method of claim 1, wherein the second pulses originate from one or more physiological pulse generators in the subject.

26. A computer readable medium comprising instructions which, when executed by a processor, cause the processor to monitor the integrity of a connection system between first and second fluid containing systems, wherein the first fluid containing system comprises a first pulse generator, and the second fluid containing system comprises a second pulse generator, and wherein at least one pressure sensor is arranged in the first fluid containing system to detect first pulses originating from the first pulse generator and second pulses originating from the second pulse generator, said processor monitors the integrity of the connection system by:

generating a time-dependent monitoring signal based on measurement data obtained from said at least one pressure sensor such that the monitoring signal contains a sequence of apparent pulses, said apparent pulses representing a superposition of the second pulses on the first pulses when the connection system is intact;

processing the monitoring signal to calculate a parameter value based on a pulse feature of at least one of the apparent pulses in the monitoring signal, the parameter value representing a disturbance caused by the superposition of the second pulses on the first pulses; and

determining the integrity of the connection system based at least partly on the parameter value.

27. A device for monitoring the integrity of a connection system between first and second fluid containing systems, wherein the first fluid containing system comprises a first pulse generator, and the second fluid containing system comprises a second pulse generator, and wherein at least one pressure sensor is arranged in the first fluid containing system and configured to detect first pulses originating from the first pulse generator and second pulses originating from the second pulse generator, said device comprising:

means for generating a time-dependent monitoring signal based on measurement data obtained from said at least one pressure sensor such that the monitoring signal contains a sequence of apparent pulses, said apparent pulses representing a superposition of the second pulses on the first pulses when the connection system is intact;

means for processing the monitoring signal to calculate a parameter value based on a pulse feature of at least one of the apparent pulses in the monitoring signal, the parameter value representing a disturbance caused by the superposition of the second pulses on the first pulses; and

means for determining the integrity of the connection system based at least partly on the parameter value.

28. A device for monitoring the integrity of a connection system between first and second fluid containing systems, wherein the first fluid containing system comprises a first pulse generator, and the second fluid containing system comprises a second pulse generator, and wherein at least one pressure sensor is arranged in the first fluid containing system and configured to detect first pulses originating from the first pulse generator and second pulses originating from the second pulse generator, said device comprising:

an input configured to obtain measurement data from said at least one pressure sensor, and

a signal processor connected to said input and being configured to;

generate a time-dependent monitoring signal based on the measurement data, such that the monitoring signal contains a sequence of apparent pulses, said apparent pulses representing a superposition of the second pulses on the first pulses when the connection system is intact;

process the monitoring signal for calculation of a parameter value based on a pulse feature of at least one of the apparent pulses in the monitoring signal, the parameter value representing a disturbance caused by the superposition of the second pulses on the first pulses; and

determine the integrity of the connection system based at least partly on the parameter value.