Detection of a disruption of a fluid connection between two fluid containing systems

Patent metadata

Field	Value
Publication number	US-11077240-B2
Application number	US-201615573285-A
Country	US
Kind code	B2
Filing date	Jun 3, 2016
Priority date	Jun 25, 2015
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

A monitoring system ( 9 ) performs a method for detecting a disruption of a fluid connection between a first fluid containing system and a second fluid containing system. The monitoring system generates a monitoring signal (M 1 ) which is representative of a fluid pressure in respect of the first fluid containing system and which is responsive to the disruption of the fluid connection, and a tracking signal (T 1 ) which corresponds to and is more smoothed over time than the monitoring signal (M 1 ). The monitoring system ( 9 ) further sets a detection range (M 1 L, M 1 H) in a given relation to the tracking signal (T 1 ) so that the detection range (M 1 L, M 1 H) follows changes in the tracking signal (T 1 ), and detects a condition indicative of the disruption by comparing a current pressure value of the monitoring signal (M 1 ) to the detection range (M 1 L, M 1 H). The monitoring system ( 9 ) may be connected to or part of an apparatus for blood treatment and operable to detect a disconnection of an extracorporeal blood circuit from a vascular system of a patient, e.g. downstream of a blood pump in the extracorporeal blood circuit.

First claim

The invention claimed is:

1. A monitoring system for detecting a disruption of a fluid connection between a first fluid containing system and a second fluid containing system, the monitoring system comprising:
a signal generating arrangement configured to generate a monitoring signal which is representative of a fluid pressure in respect of the first fluid containing system and which is responsive to the disruption of the fluid connection, and
a disruption detector configured to detect a condition indicative of the disruption by comparing a current pressure value of the monitoring signal to a detection range,
wherein the signal generating arrangement is configured to generate a tracking signal which corresponds to and is more smoothed over time than the monitoring signal,
wherein the signal generating arrangement comprises a first signal filter for generating the monitoring signal and a second signal filter for generating the tracking signal,
wherein the first and second signal filters define a respective lowest frequency passband extending between lower and upper limit frequencies, wherein the upper limit frequency of the second signal filter is lower in frequency than the upper limit frequency of the first signal filter, and
wherein the disruption detector is configured to set the detection range in a given relation to the tracking signal so that the detection range follows changes in the tracking signal.

2. The monitoring system of claim 1 , wherein the signal generating arrangement is configured to generate the monitoring signal to represent faster fluid pressure changes than the tracking signal.

3. The monitoring system of claim 1 , wherein the first and second signal filters comprises a respective low-pass filter, wherein the upper limit frequency is a cutoff frequency of the respective low-pass filter.

4. The monitoring system of claim 1 , wherein the ratio of the upper limit frequencies of the first and second signal filters is at least 2.

5. The monitoring system of claim 1 , wherein at least one of the first and second signal filters comprises a moving average filter which is configured to generate a time-sequence of filtered values based on signal values in an input signal, wherein each filtered value is computed as an average of the signal values within a time window in the input signal, the moving average filter being configured to, based on a reference signal indicative of a current operating frequency of a repetitive pulse generator in the first or second fluid containing system, set the length of the time window to effectively match a given whole number of pulsations generated by the repetitive pulse generator.

6. The monitoring system of claim 5 , wherein the moving average filter is included in the first signal filter and in the second signal filter, and wherein the moving average filter in the first signal filter is configured to set the length of the time window to effectively match a first number of the pulsations, and the moving average filter in the second signal filter is configured to set the length of the time window to effectively match a second number of the pulsations, and wherein the second number is larger than the first number.

7. The monitoring system of claim 6 , wherein the ratio of the second number to the first number is at least 2.

8. The monitoring system of claim 1 , wherein the first and second signal filters are configured to effectively remove frequency components corresponding to an operating frequency of one or more repetitive pulse generators in the first and second fluid containing systems.

9. The monitoring system of claim 1 , wherein the signal generating arrangement comprises at least one pressure sensor and is configured to generate the monitoring signal based on at least one pressure signal produced by the at least one pressure sensor.

10. The monitoring system of claim 9 , wherein the signal generating arrangement is configured to generate the tracking signal based on the at least one pressure signal or the monitoring signal.

11. The monitoring system of claim 10 , which is configured to, after the respective disturbance period, cause the signal generating arrangement to re-start generating the tracking signal based on the monitoring signal or the at least one pressure signal, while excluding data samples originating during the respective disturbance period.

12. The monitoring system of claim 9 , wherein the signal generating arrangement comprises a signal conditioner configured to process and supply at least one of the monitoring signal and the tracking signal to the disruption detector, the signal conditioner being configured to detect undesired peaks in the at least one of the monitoring signal and the tracking signal and effectively remove the respective undesired peak by replacing the respective undesired peak with a signal segment that connects a starting point of the respective undesired peak with an end point of the respective undesired peak.

13. The monitoring system of claim 9 , which is configured to, when detecting the condition indicative of a disruption, generate a control signal for disabling one or more pulse generators in the first fluid containing system, analyze the at least one pressure signal for detection of at least one pressure pulsation originating from one or more pulse generators in the second fluid containing system, and, if the at least one pressure pulsation is deemed to be absent in the at least one pressure signal, generate an alarm signal.

14. The monitoring system of claim 1 , wherein the disruption detector is configured to receive a disturbance signal indicative of time points of forecasted or actual disturbances in the monitoring signal and take, based on the disturbance signal, precautionary measures to reduce the impact of the forecasted or actual disturbances on the detection of the condition indicative of the disruption.

15. The monitoring system of claim 14 , wherein the disruption detector is configured to, based on the time points of the forecasted or actual disturbances, determine disturbance periods and disable the detection of the condition indicative of the disruption during the respective disturbance period.

16. The monitoring system of claim 15 , wherein the disruption detector is configured to disable the detection of the condition by one of: causing the monitoring signal to be set equal to the tracking signal during the respective disturbance period, and increasing the detection range.

17. The monitoring system of claim 14 , wherein the disruption detector is configured to apply a disruption detection rule that requires the monitoring signal to fall outside the detection range during a predefined detection time period, and wherein the disruption detector is configured to increase the predefined detection time period by adding an extension time period during the respective forecasted or actual disturbance.

18. The monitoring system of claim 1 , wherein the signal generating arrangement is configured to generate the monitoring signal to represent a functional combination of first and second pressure signals from first and second pressure sensors, the first pressure signal being responsive to the disruption of the fluid connection and the second pressure signal being non-responsive to the disruption of the fluid connection, wherein the monitoring signal is generated to represent changes in fluid pressure that are present at both the first pressure sensor and the second pressure sensor while suppressing changes in fluid pressure that are present at both of the first and se

Assignees

• Gambro Lundia Ab

Inventors

• Solem Kristian
• Olde Bo
• Sternby Jan

Classifications

• A61B5/02152

  specially adapted for venous pressure · CPC title

• A61M2205/3331

  Pressure; Flow · CPC title

• A61M2205/17

  with redundant control systems · CPC title

• A61M2205/18

  with alarm · CPC title

• A61M1/3656 Primary

  Monitoring patency or flow at connection sites; Detecting disconnections · CPC title