System and method for determining blood flow rate in a vessel
First Claim
1. A method of determining the performance of a vessel which communicates blood between two locations of a patient, the method comprising:
- diverting blood from the vessel at a diversion point to obtain a flow of diverted blood in a conduit, wherein the vessel has a blood flow rate QA upstream from the diversion point and a blood flow rate QD downstream from the diversion point;
determining a flow rate QB of the diverted blood through the conduit;
generating at least one signal that is a function of the downstream flow rate QD without requiring a cross-sectional area of the vessel, wherein the downstream flow rate QD depends on the determined conduit flow rate QB and the upstream flow rate QA; and
observing the at least one signal to obtain information about the upstream flow rate QA and determine the performance of the vessel.
1 Assignment
0 Petitions
Accused Products
Abstract
A system and method are provided for determining the performance of a vessel, such as a hemodialysis access, which communicates blood between two locations of a patient. A conduit, such as an external dialysis circuit or an intravascular catheter, is provided in fluid communication with the vessel, and has a diversion point for diverting blood from the vessel into the conduit. The system further includes means for determining a flow rate of the diverted blood through the conduit. A first sensor in communication with the vessel generates at least one signal that is a function of a blood flow rate in the vessel downstream from the diversion point, wherein the downstream flow rate depends on the determined conduit flow rate and the performance of the vessel can be determined based on the signal. In addition, a processor can be provided in communication with the first sensor for determining a flow rate in the vessel upstream from the diversion point from the signal and the conduit flow rate. In a preferred embodiment, the first sensor is an ultrasonic sensor, and the at least one signal represents a time-averaged mean Doppler velocity of blood flow. Still further, additional sensors may be employed to provide a measure of the upstream flow rate as well as the conduit flow rate.
-
Citations
29 Claims
-
1. A method of determining the performance of a vessel which communicates blood between two locations of a patient, the method comprising:
-
diverting blood from the vessel at a diversion point to obtain a flow of diverted blood in a conduit, wherein the vessel has a blood flow rate QA upstream from the diversion point and a blood flow rate QD downstream from the diversion point;
determining a flow rate QB of the diverted blood through the conduit;
generating at least one signal that is a function of the downstream flow rate QD without requiring a cross-sectional area of the vessel, wherein the downstream flow rate QD depends on the determined conduit flow rate QB and the upstream flow rate QA; and
observing the at least one signal to obtain information about the upstream flow rate QA and determine the performance of the vessel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. A method for determining blood flow rate in a vessel which communicates blood between two locations of a patient, the method comprising:
-
diverting blood from the vessel at a diversion point to obtain a flow of diverted blood in a conduit, wherein the vessel has a blood flow rate QA upstream from the diversion point and a blood flow rate QD downstream from the diversion point;
determining a flow rate QB of the diverted blood through the conduit;
generating at least one signal that is a function of QD without requiring a cross-sectional area of the vessel, wherein QD depends on QB and QA; and
processing the at least one signal and QB to obtain QA. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
-
Specification