Measurement of a blood flow rate in hemodialysis shunts
First Claim
1. A method for obtaining a measure of blood flow rate in a patient arterio-venous shunt, the arterio-venous shunt being connected to an extracorporeal blood circulating system, the extracorporeal blood circulating system having a dialyzer connected to the arterio-venous shunt by a first and a second line, wherein the first line directs blood from the arterio-venous shunt to the dialyzer and the second line directs blood from the dialyzer to the arterio-venous shunt, the method comprising the steps of:
- (a) connecting the dialyzer to the arterio-venous shunt with an inlet of the first line located downstream from an outlet of the second line;
(b) providing a change in a parameter of the blood flowing in the extracorporeal blood circulating system; and
(c) obtaining the measure of blood flow rate in the arterio-venous shunt based upon a resulting dilution curve by the change in said parameter of the blood and a dialyzer blood flow rate.
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Accused Products
Abstract
The measurement of blood flow in a dialysis shunt is obtained by injection of an indicator material into a venous line leading from dialysis equipment to the shunt. The blood flow in an arterial line leading from the shunt at a location downstream of the venous line to the dialysis equipment is monitored by an arterial line sensor for the presence of the indicator material. A detector connected to the sensor provides a dilution curve in response to the presence of the indicator material and the blood flow in the shunt is calculated from the area under the dilution curve. The locations of the arterial and venous lines in the shunt can be reversed to obtain a measurement of blood recirculation from the venous line into the arterial line.
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Citations
44 Claims
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1. A method for obtaining a measure of blood flow rate in a patient arterio-venous shunt, the arterio-venous shunt being connected to an extracorporeal blood circulating system, the extracorporeal blood circulating system having a dialyzer connected to the arterio-venous shunt by a first and a second line, wherein the first line directs blood from the arterio-venous shunt to the dialyzer and the second line directs blood from the dialyzer to the arterio-venous shunt, the method comprising the steps of:
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(a) connecting the dialyzer to the arterio-venous shunt with an inlet of the first line located downstream from an outlet of the second line; (b) providing a change in a parameter of the blood flowing in the extracorporeal blood circulating system; and (c) obtaining the measure of blood flow rate in the arterio-venous shunt based upon a resulting dilution curve by the change in said parameter of the blood and a dialyzer blood flow rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for deriving a measure of blood flow rate in an arterio-venous shunt, wherein the arterio-venous shunt is connected to a dialysis system including a dialyzer, an arterial blood line and a venous blood line which connect the dialyzer to the arterio-venous shunt, the method comprising the steps of:
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(a) connecting an inlet of the arterial blood line to the arterio-venous shunt at a location downstream from an outlet of the venous blood line; (b) imparting a change in a parameter of blood flowing in the dialysis system; and (c) deriving the measure of blood flow rate in the arterio-venous shunt in response to the changed blood parameter and its corresponding resulting dilution curve. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for ascertaining a measure of blood flow rate in an arterio-venous shunt, the arterio-venous shunt being connected to a hemodialysis circulating system having a dialyzer, an arterial line and a venous line, the method comprising the steps of:
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(a) connecting the arterial and venous lines to the arterio-venous shunt so that the arterial line removing blood from the arterio-venous shunt is downstream from the venous line returning blood to the arterio-venous shunt; (b) inducing a change in a characteristic of the blood flowing in the hemodialysis circulating system; and (c) ascertaining the measure of blood flow rate in the arterio-venous shunt based upon a resulting dilution curve by the change in said characteristic of the blood and a dialyzer blood flow rate. - View Dependent Claims (34)
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24. A method for deriving a measure of blood flow rate in an arterio-venous shunt, the arterio-venous shunt connectable to a hemodialysis circulating system having a dialyzer, an arterial line and a venous line, the method comprising the steps of:
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(a) connecting the arterial and venous lines in a way the arterial line withdrawing blood from the arterio-venous shunt is downstream from the venous line returning blood to the arterio-venous shunt; (b) providing a change in a blood characteristic in the hemodialysis circulating system; and (c) deriving the measure of blood flow rate in the arterio-venous shunt based upon a resulting dilution curve by the change in said blood characteristic and a dialyzer blood flow rate. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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Specification