Blood flow monitor with visual display

• US 20070167789A1
• Filed: 11/08/2006
• Published: 07/19/2007
• Est. Priority Date: 11/16/2005
• Status: Active Grant

• Current Assignee: Coopersurgical Incorporated (The Cooper Cos., Inc.)
• Original Assignee: Cook Vascular Incorporated (Cook Group Incorporated)
• Inventors: Henry, Donald
• Granted Patent: US 9,028,415 B2
• Time in Patent Office: Days
• US Class Current: 600/454
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/6876 Blood vessel
• CPC Class Codes: A61B 5/6884 Clamps or clips
• 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 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00

Abstract

A blood flow monitor with a visual display. The monitor may include a probe monitoring circuit configured to be associated with a blood vessel. The probe monitoring circuit may transmit a burst signal and receive a reflected signal, where a frequency shift in the reflected signal represents a flow rate associated with the blood vessel. A mixer may be provided in electrical communication with the probe. A signal processing circuit in electrical communication with the output of the mixer may be configured to drive the visual display with a signal representing the flow rate associated with the blood vessel.

Claims

1. A blood flow monitor comprising:

a visual display;

a probe monitoring circuit configured to be associated with a blood vessel, where the probe monitoring circuit is configured to transmit a burst signal and receive a reflected signal, where a frequency shift in the reflected signal represents a flow rate associated with the blood vessel;

a mixer comprising an input in electrical communication with the probe monitoring circuit and an output, where the mixer is configured to output a signal at a frequency of the frequency shift; and

a signal processing circuit comprising an input in electrical communication with the output of the mixer and an output in electrical communication with the visual display, where the signal processing circuit is configured to drive the visual display with a signal representing the flow rate associated with the blood vessel.

2. The blood flow monitor as recited in claim 1, where the signal processing circuit includes an amplifier in electrical communication with the output of the mixer.

3. The blood flow monitor as recited in claim 2, where the signal processing circuit includes filtering logic configured to implement a low pass filter.

4. The blood flow monitor as recited in claim 3, where the amplifier includes an output and the filtering logic includes an input, where the output of the amplifier is in electrical communication with the input of the filtering logic.

5. The blood flow monitor as recited in claim 1, where the signal processing circuit includes a scaling logic configured to generate a scaled signal representing the flow rate associated with the blood vessel.

6. The blood flow monitor as recited in claim 5, where the scaled signal has a frequency that varies corresponding to the flow rate associated with the blood vessel.

7. The blood flow monitor as recited in claim 6, where the flow rate associated with the blood vessel is in a range of flow rates, where the scaled signal represents a portion of the range of flow rates.

8. The blood flow monitor as recited in claim 7, where the range of flow rates is defined by a low rate range and a high rate range, where the scale signal represents the low rate range.

9. The blood flow monitor as recited in claim 8, further comprising a speaker in electrical communication with the output of the mixer, where the speaker is configured to produce an audible sound indicative of flow rates in the high rate range.

10. The blood flow monitor as recited in claim 1, where the visual display is selected from the group consisting of a LED bar graph, a LCD bar graph, a calibrated needle, and a numeric display.

11. The blood flow monitor as recited in claim 1, where the probe monitoring circuit includes a piezoelectric crystal, where the pieozoelectric crystal transmits the burst signal and receives the reflected signal.

12. The blood flow monitor as recited in claim 11, where the probe monitoring circuit is associated with the blood vessel such that the piezoelectric crystal directly contacts the blood vessel, and where the probe monitoring circuit includes a probe that is configured such as at least a portion of the probe is implanted in a patient.

13. The blood flow monitor as recited in claim 1, where the burst signal is at an ultrasonic frequency.

14. A signal processing circuit comprising:

an input channel configured to receive an input signal representing a flow rate through a blood vessel;

an output channel configured to output an output signal; and

a scaling logic connected between the input channel and the output channel, where the scaling logic is configured to generate a scaled signal capable of driving a visual display with the flow rate associated with the blood vessel.

15. The signal processing circuit as recited in claim 14, where the scaled signal has a frequency that varies corresponding to the flow rate associated with the blood vessel.

16. The signal processing circuit as recited in claim 15, where the flow rate associated with the blood vessel is in a range of flow rates, where the scaled signal represents a portion of the range of flow rates.

17. The blood flow monitor as recited in claim 16, where the range of flow rates is defined by a low rate range and a high rate range, where the scaled signal represents the low rate range.

18. The signal processing circuit as recited in claim 14, further comprising an amplifier prior to the scaling logic, and a display driver after the scaling logic.

19. A method of monitoring the blood flow rate through a blood vessel, the method comprising:

transmitting a burst signal proximate to a blood vessel;

receiving a reflected signal, where a frequency shift in the reflected signal represents a flow rate associated with the blood vessel;

driving a visual display with the flow rate associated with the blood vessel.

20. The method as recited in claim 19, where in the driving step, a full scale of the visual display indicates a full scale flow rate that corresponds with less than the maximum flow rate associated with the blood vessel.