Method of monitoring a vascular access and an apparatus for extracorporeal treatment of blood with a device for monitoring the vascular access
First Claim
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1. A method of monitoring a vascular access during an extracorporeal blood treatment comprising the steps of:
- (a) providing blood from the vascular access of a subject through an extracorporeal blood path comprising an arterial line in fluid communication with the vascular access, a blood treatment device, and a venous line in fluid communication with the vascular access;
(b) measuring fluid pressure within the arterial and venous lines; and
(c) calculating first and second characteristic values for the integrity of the vascular access from the measured arterial and venous pressures;
wherein the integrity of the vascular access is determined by comparing the first and second characteristic values to first and second ranges of predetermined values.
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Abstract
A method and device for monitoring a vascular access during a dialysis treatment in which the pressures in both the arterial and venous branches of the extracorporeal blood system are monitored by pressure sensors. Characteristic values for the condition of the vascular access are calculated in a computer unit from the pressures in the arterial and venous branches of the extracorporeal system, and these values are analyzed in an analyzer unit to detect a defective vascular access.
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Citations
10 Claims
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1. A method of monitoring a vascular access during an extracorporeal blood treatment comprising the steps of:
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(a) providing blood from the vascular access of a subject through an extracorporeal blood path comprising an arterial line in fluid communication with the vascular access, a blood treatment device, and a venous line in fluid communication with the vascular access;
(b) measuring fluid pressure within the arterial and venous lines; and
(c) calculating first and second characteristic values for the integrity of the vascular access from the measured arterial and venous pressures;
wherein the integrity of the vascular access is determined by comparing the first and second characteristic values to first and second ranges of predetermined values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
(i) calculating the first characteristic value by calculating a sum of the measured pressure in the venous line and the measured pressure in the arterial line according to the equation;
PS=PVEN+PART; and
(ii) calculating the second characteristic value by calculating a difference between the measured pressure in the venous line and the measured pressure in the arterial line according to the equation;
Δ
P=PVEN−
PART.
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3. The method of claim 2, wherein successive measurements of the arterial and venous pressures are taken.
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4. The method of claim 3, wherein step (c) further comprises the steps of:
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(i) calculating a change in the pressure sum for successive measurements by subtracting the sum for a first measurement from the sum for a second measurement; and
(ii) calculating a change in the pressure difference between successive measurements by subtracting the difference for the first measurement from the difference for the second measurement.
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5. The method of claim 4, wherein step (c) further comprises the steps of:
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(i) calculating the first characteristic value by adding the changes in the sum for a predetermined number of the successive pressure measurements; and
(ii) calculating the second characteristic value by adding the changes in the pressure difference for the predetermined number of the successive pressure measurements.
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6. The method of claim 5, further comprising the step of generating a safe response in reaction to characteristic values selected from the group consisting of:
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(i) a first characteristic value below the first range of values, and a second characteristic value below the second range of values, and (ii) a first characteristic value above the first range of values, and a second characteristic value above the second range of values.
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7. The method of claim 6, wherein the safe response is an alarm selected from the group consisting of visual and audible alarms.
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8. The method of claim 6, wherein the safe response comprises closing a cutoff clamp in the venous line.
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9. The method of claim 6, wherein the safe response comprises interrupting the provision of blood to the extracorporeal blood path.
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10. The method of claim 6, wherein the safe response comprises stopping a blood pump provided in the arterial line.
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