Extravasation detector

• US 20040176690A1
• Filed: 12/10/2003
• Published: 09/09/2004
• Est. Priority Date: 12/10/2002
• Status: Active Grant

• Current Assignee: Respinor As
• Original Assignee: Neorad AS
• Inventors: Brabrand, Knut
• Granted Patent: US 7,801,583 B2
• Time in Patent Office: Days
• US Class Current: 600/454
• 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: 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

Abstract

Ultrasound Doppler probe 2 is placed above the vein downstream of the infusion site. Processor 4 converts the output from the probe 2 into a form that may be displayed as an image on display unit 5. It also determines whether the velocity corresponds to a flow of contrast medium along the vein. If the cannula 13 is properly sited and the contrast medium flows as desired along the vein, this will lead to an increased flow velocity in the vein. This is detected by ultrasound probe 2 and, as described above, the processor unit 4 will therefore determine that no extravasation has occurred. However, where extravasation of contrast medium occurs this results in a low or zero velocity output from the probe 2 from which the processor unit 4 determines that extravasation has occurred. It therefore immediately sends a “stop” signal to pump controller 11 which stops pump 10.

Claims

1. A method of detecting extravasation during the infusion of a substance into a blood vessel comprising the step of detecting a change in the flow velocity within the blood vessel downstream of the point of infusion.

2. A method as claimed in claim 1, wherein an array of detector elements is arranged substantially transverse to the direction of flow of the blood vessel downstream of the point of infusion so as to locate at least one said detector element over the vessel.

3. A method as claimed in claim 1 or 2, wherein the flow velocity within the blood vessel is measured at a plurality of points spaced apart along the vessel and downstream of the point of infusion.

4. A method as claimed in claim 1, 2 or 3, wherein the infusion is a venous infusion of a contrast agent.

5. A method as claimed in any preceding claim, wherein flow velocity changes are continuously or repeatedly monitored during the procedure.

6. A method as claimed in any preceding claim, further comprising the provision of a notification that extravasation has occurred.

7. A method as claimed in any preceding claim, further comprising the automatic shutdown of the infusion in response to the detection of extravasation.

13. An apparatus as claimed in any of claims 8 to 12, or a method as claimed in any of claims 1 to 7, wherein the detector is an ultrasound Doppler probe.

14. An apparatus or method as claimed in claim 2 or 9, wherein the detector elements are ultrasound transducer elements.

8. An apparatus for detecting extravasation during the infusion of a substance into a blood vessel comprising a detector for detecting a change in the flow velocity within the blood vessel downstream of the point of infusion, the apparatus being arranged to provide an output signal when extravasation occurs.

9. An apparatus as claimed in claim 8, wherein the detector comprises an array of detector elements that may be arranged substantially transverse to the direction of flow of the blood vessel so as to locate at least one said detector element over the vessel.

10. An apparatus as claimed in claim 8 or 9, the detector being adapted to measure the flow velocity within the blood vessel at a plurality of points spaced apart along the vessel and downstream of the point of infusion.

11. An apparatus as claimed in claim 8, 9 or 10, wherein the output signal is a notification, alarm or the like.

12. An apparatus as claimed in any of claims 8 to 11, wherein the output signal is a control signal to control the infusion.

15. A system for giving an infusion comprising an infusion pump arranged to infuse a substance into a blood vessel and an extravasation detector according to any of claims 8 to 14, wherein the detector apparatus is arranged to control the infusion pump.