Vascular Access Monitoring Device

• US 20120271161A1
• Filed: 06/18/2010
• Published: 10/25/2012
• Est. Priority Date: 06/18/2009
• Status: Active Grant

• Current Assignee: Quanta Dialysis Technologies Ltd.
• Original Assignee: Quanta Dialysis Technologies Ltd.
• Inventors: Buckberry, Clive
• Granted Patent: US 9,480,455 B2
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/02042 Determining blood loss or bleeding, e.g. during a surgical procedure
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/0833 involving detecting or locating foreign bodies or organic structures
• CPC Class Codes: A61B 8/0841 for locating instruments
• CPC Class Codes: A61B 8/4227 characterised by straps, belts, cuffs or braces
• 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 2205/3375 Acoustical, e.g. ultrasonic, measuring means
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: A61M 5/16836 by sensing tissue properties at the infusion site, e.g. for detecting infiltration detecting tissue temperature for diagnostic purposes A61M39/0247

Abstract

A vascular access monitoring device for monitoring characteristics of a skin piercing vascular access device comprising: an acoustic sensor operable to detect an acoustic emission created by flow through said vascular access device and produce an electrical signal indicative of said emission; electronics processing means for processing and monitoring said electrical signal, and to determine, by identifying a change of characteristic of said signal, the possibility that the vascular access device has become dislodged from its normal working position.

Claims

1. A vascular access monitoring device for monitoring characteristics of a skin piercing vascular access device, the monitoring device comprising:

an acoustic sensor operable to detect an acoustic emission created by flow through said vascular access device and produce an electrical signal indicative of said emission; and

electronics processing means for processing and monitoring said electrical signal, and to determine, by identifying a change of characteristic of said signal, the possibility that the vascular access device has become dislodged from its normal working position.

2. The monitoring device according to claim 1, wherein:

the acoustic sensor is adapted for location on the patient'"'"'s skin adjacent a vascular access point.

3. The monitoring device according to claim 1, wherein:

the acoustic sensor is adapted for location on a flow conduit attached to the vascular access device.

4. The monitoring device according to claim 1 wherein:

the electronics processing means comprises an electrical input means for receiving a signal form an extra corporeal blood pump.

5. The monitoring device according to claim 4, wherein:

said extra corporeal blood pump is arranged for intermittent pumping and the electronics processing means receives a signal indicative of the pumping cycle of said extra corporeal blood pump.

6. The monitoring device according to claim 5, wherein:

the electronics processing means is phase locked with the pump cycle of the extracorporeal blood pump and wherein said electronics processing means compares the acoustic signals on successive cycles of the extracorporeal pump as it induces flow through said vascular access device.

7. The monitoring device according to claim 1 wherein:

the electronics processing means monitors background noise and subtracts the background noise from the signal indicative of the acoustic emissions.

8. The monitoring device according to claim 4, wherein:

the device monitors background noise in between pump cycles of the extracorporeal blood pump.

9. The monitoring device according to claim 7, wherein:

the background noise includes noise created by a patient'"'"'s heartbeat.

10. The monitoring device according to claim 9, further comprising:

a second acoustic sensor located on the patients body, remote from said vascular access device, for measuring the background noise.

11. The monitoring device according to claim 10, wherein:

a single acoustic sensor is used for creating a signal indicative of acoustic noise due to flow through the vascular access device and indicative of the background noise.

12. The monitoring device according to claim 1, further comprising:

a second monitoring device for monitoring the presence of the skin piercing vascular access device, the second monitoring device including

a mount having an ultrasonic transmitter and an ultrasonic receiver therein,

attachment means for attaching the mount to a patient adjacent a vascular access point such that, in use, a vascular access device entering the patient at the vascular access point, passes underneath a sensing section of the base, and

control electronics to monitor the signal received at the receiver;

wherein when the vascular access device is underneath said sensing section, ultrasound produced by said transmitter passes through the patient skin and is reflected by the patients body tissues and by the vascular access device, and when the vascular access device is not underneath said sensing section, ultrasound produced by said transmitter passes through the patients skin and is reflected by the patients body tissue only, and wherein the control electronics detects the presence of a vascular access device by performing a comparison on the received ultrasonic signal.

13. The device according to claim 12, wherein:

the transmitter of the second monitoring device periodically emits an ultrasonic pulse and the receiver receives a reflected ultrasonic pulse.

14. The device according to claim 12, wherein:

the control electronics monitor the received signal from the receiver of the second monitoring device received within in a particular time window, that time window being based on a maximum and minimum expected time of flight of the ultrasonic pulse from the transmitter, to the needle and back to the receiver.

15. The device according to claim 14, wherein:

the time window exceeds the expected window by a factor relating to a margin of error.

16. The device according to claim 12, wherein:

the sensor of the second monitoring device is configured to identify ultrasonic reflections from first and second surfaces, one of which is the vascular access device, and the sensor detects a change in the received signals.

17. The device according to claim 12, wherein:

when the vascular access device is located beneath the sensing section of the second monitoring device, the reflected signal shows altered characteristics.

18. The device according to claim 17, wherein:

by comparing subsequent received signals received from the receiver of the second monitoring device, a change in the received signal can be identified by the control electronics and a warning can be raised that the vascular access device has become dislodged.

19. The device according to claim 17, wherein:

by comparing the received signal to the transmitted signal, characteristics of the received signal can be identified by the control electronics of the second monitoring device and a warning can be raised when the vascular access device becomes dislodged.

20. The device according to claim 17, wherein:

by comparing the received signal from the receiver of the second monitoring device to a model received signal, characteristics of the received signal can be identified by the control electronics of the second monitoring device and if they deviate from the model signal more than a prescribed amount, a warning can be raised that the vascular access device has become dislodged.

21. The device according to claim 12, wherein:

the amplitude of at least a part of the reflected signal received by the receiver of the second monitoring device changes dependant on the presence of the vascular access device.

22. The device according to claim 12, further comprising:

an ultrasonic coupling means for, in use, ultrasonically coupling the second monitoring device to a patient'"'"'s skin.

23. The device according to claim 12, further comprising:

means for connection to a medical apparatus.

24. The device according to claim 23, wherein:

when dislodgement of the vascular access device is sensed, the control electronics sends a signal indicative of that to the medical apparatus, the signal forming a part of the control algorithm for the medical apparatus.

25. The device according to claim 23, wherein:

the control electronics are configured to periodically receive an interrogation from the medical apparatus to perform a self diagnosis check, to carry out a self diagnosis check and to send a signal to the medical apparatus indicative that the diagnosis check was successful and the device is working properly.