ACCESS DISCONNECT DETECTION

• US 20090088612A1
• Filed: 09/27/2007
• Published: 04/02/2009
• Est. Priority Date: 09/27/2007
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Inventors: Bouton, Chad E.
• Granted Patent: US 9,011,334 B2
• Time in Patent Office: Days
• US Class Current: 600/309
• CPC Class Codes: A61B 5/02042 Determining blood loss or bleeding, e.g. during a surgical procedure
• 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

Abstract

Techniques are disclosed for monitoring the flow of blood returning to a patient from an extracorporeal therapy machine, such as a hemodialysis machine or an apheresis machine. Blood returning from such a machine is pumped, typically by a peristaltic pump, which returns the blood in pulsed flow or pulses. This flow can be sensed by Doppler flow sensors or accelerometers as it returns to the patient. If the flow is interrupted by dislodgement of the venous access needle, or by leaking of blood from the needle, these sensors will detect significantly different flow or vibrations. A controller can then cease therapy, alert a caregiver, or sound an alarm.

Claims

1. An accelerometer-based access disconnect detector, comprising:

an accelerometer configured for mounting on a patient near an access site;

signal processing circuitry, the signal processing circuitry operably connected to the accelerometer for receiving indications from the accelerometer; and

a controller configured for receiving readings from the signal processing circuitry and for sending a signal upon a change in the readings, wherein the controller is in communication with or is part of a therapy machine for receiving blood and returning blood to a patient.

2. The access disconnect detector of claim 1, further comprising a communications circuit operably connected to the signal processing circuitry, the communications circuit having a wired or wireless connection to the controller.

3. The access disconnect detector of claim 1, further comprising a flexible pad for mounting at least the accelerometer and the signal processing circuitry on the patient.

4. The access disconnect detector of claim 1, further comprising a computer program on a computer-readable medium configured for use with the controller for calculating a flow rate of blood from the accelerometer, for calculating a change in the flow rate, and for determining when the change has occurred.

5. The access disconnect detector of claim 1, further comprising an output device operably connected to the controller for alerting the patient or a caregiver.

6. The access disconnect detector of claim 1, wherein the therapy machine is a hemodialysis machine, and further comprising the hemodialysis machine.

7. An access disconnect detector, the detector comprising:

a sensor for determining a flow of blood in a vein of a patient, the blood being returned from an extracorporeal blood therapy and the sensor configured for mounting on the patient near an access site;

signal processing circuitry, the circuitry operably connected to the sensor for determining a flow rate of blood being returned from the extracorporeal therapy; and

a communications circuit connected to the signal processing circuitry, wherein the sensor is configured for sensing the flow rate of blood through the vein and for generating readings indicative of the flow, and the signal processing circuitry is configured for receiving the readings and sending the readings to the communications circuit.

8. The access disconnect detector of claim 7, further comprising a controller configured for receiving readings from the signal processing circuitry or the communications circuit, and further comprising a computer program on a computer-readable medium configured for use with the controller for calculating the flow rate of blood from the accelerometer, for calculating a change in the flow rate, and for determining when the change has occurred.

9. The access disconnect detector of claim 7, wherein the sensor is an accelerometer.

10. The access disconnect detector of claim 7, wherein the sensor is a Doppler flow sensor.

11. A method for detecting an access disconnection, the method comprising:

mounting a sensor on a patient near an access site;

establishing a baseline sensor reading of the patient;

detecting readings indicative of a pulsatile flow of blood with the sensor;

comparing additional readings during an extracorporeal blood therapy with the readings indicative of pulsatile flow;

deciding whether the additional readings are significantly different from the readings of pulsatile flow; and

sending a signal if the sensor readings are significantly different from the readings of pulsatile flow.

12. The method of claim 11, further comprising averaging the additional readings over a period of time before the step of comparing.

13. The method of claim 11, wherein the sensor is selected from the group consisting of an accelerometer and a Doppler flow sensor.

14. The method of claim 11, further comprising filtering readings from the sensor of indications of a heart beat of the patient.

15. The method of claim 11, further comprising comparing the additional readings with the baseline readings indicative of the flow sensor.

16. A sensor-based method for detecting blood flow, the method comprising:

mounting a sensor indicative of blood flow to a patient near an access site;

detecting first readings from the sensor indicative of a flow of blood from a pulsing mechanical pump;

beginning an extracorporeal therapy with the patient;

monitoring additional readings from the sensor during the therapy;

deciding whether the additional readings are different from the first readings; and

sending an alert if the readings are different from the first readings.

17. The method of claim 16, wherein the first readings are baseline readings of blood flow of the patient.

18. The method of claim 16, wherein the sensor is an accelerometer or a flow sensor.

19. The method of claim 16, further comprising comparing the flow of blood to the patient to a flow of blood from the patient, and sending an alert if the flows are different.