Extravasation detector
First Claim
1. A method of detecting extravasation during a procedure infusing a substance into a blood vessel, comprising the steps of infusing a substance into the blood vessel;
- generating a first signal proportional to a flow velocity within the blood vessel downstream of the point of infusion, at a first time;
generating a second signal proportional to the flow velocity within the blood vessel downstream of the point of infusion, at a second time;
generating a third signal representing an increase in flow velocity, based on the first and second signals; and
generating a fourth signal indicating extravasation if an increase in flow velocity represented by the third signal is less than a threshold value.
2 Assignments
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Accused Products
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.
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Citations
18 Claims
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1. A method of detecting extravasation during a procedure infusing a substance into a blood vessel, comprising the steps of infusing a substance into the blood vessel;
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generating a first signal proportional to a flow velocity within the blood vessel downstream of the point of infusion, at a first time; generating a second signal proportional to the flow velocity within the blood vessel downstream of the point of infusion, at a second time; generating a third signal representing an increase in flow velocity, based on the first and second signals; and generating a fourth signal indicating extravasation if an increase in flow velocity represented by the third signal is less than a threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for detecting extravasation during an intended infusion of a substance into a blood vessel at a point of infusion, comprising:
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a detector for generating a flow signal corresponding to a flow velocity within the blood vessel downstream of the point of infusion; and a controller coupled to the detector and configured to; determine a first flow velocity at a first time based on the flow signal; determine a second flow velocity at a second time during infusion based on the flow signal; and generate an output signal indicating occurrence of extravasation based on the difference between the first flow velocity and the second flow velocity. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification