APPARATUS AND METHOD FOR DETECTING DISCONNECTION OF AN INTRAVASCULAR ACCESS DEVICE
First Claim
1. A system for detecting the disconnection of a vascular access device from a blood vessel or vascular graft, comprising:
- a fluid delivery device for providing fluid through a first conduit into a first site of the blood vessel or graft;
a first electrode in contact with the lumen of the first conduit;
a second electrode in fluid communication with a second site of the blood vessel or graft;
an electronic circuit connected to the first and second electrodes, and configured to deliver a control signal to the first and second electrodes in order to measure the electrical resistance of a fluid between the first and second electrodes, whereinat least one of the electrodes is located closer to the blood vessel or graft than to the fluid delivery device.
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Accused Products
Abstract
An apparatus and method are disclosed for detecting the disconnection of a vascular access device such as a needle, cannula or catheter from a blood vessel or vascular graft segment. A pair of electrodes is placed in direct contact with fluid or blood in fluid communication with the vascular segment. In one embodiment, the electrodes are incorporated into a pair of connectors connecting arterial and venous catheters to arterial and venous tubes leading to and from an extracorporeal blood flow apparatus. Wires leading from the electrodes to a detecting circuit can be incorporated into a pair of double lumen arterial and venous tubes connecting the blood flow apparatus to the blood vessel or vascular graft. The detecting circuit is configured to provide a low-voltage alternating current signal to the electrodes to measure the electrical resistance between the electrodes, minimizing both the duration and amount of current being delivered. Detection of an increase in electrical resistance between the electrodes exceeding a pre-determined threshold value may be used to indicate a possible disconnection of the vascular access device.
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Citations
23 Claims
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1. A system for detecting the disconnection of a vascular access device from a blood vessel or vascular graft, comprising:
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a fluid delivery device for providing fluid through a first conduit into a first site of the blood vessel or graft; a first electrode in contact with the lumen of the first conduit; a second electrode in fluid communication with a second site of the blood vessel or graft; an electronic circuit connected to the first and second electrodes, and configured to deliver a control signal to the first and second electrodes in order to measure the electrical resistance of a fluid between the first and second electrodes, wherein at least one of the electrodes is located closer to the blood vessel or graft than to the fluid delivery device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for monitoring the continuity between a vascular access device and a blood vessel or vascular graft segment, comprising:
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a first and second vascular connector, the first connector being attached on a proximal end to a distal end of a fluid-carrying lumen of a first double-lumen tube, and the second connector being attached on a proximal end to a distal end of a fluid-carrying lumen of a second double-lumen tube, the first connector comprising a first electrode in contact with a lumen of the first connector and electrically connected to a wire within a wire-carrying lumen of the first double-lumen tube, and the second connector comprising a second electrode in contact with a lumen of the second connector and electrically connected to a wire within a wire-carrying lumen of the second double-lumen tube, wherein, the wire within the first double-lumen tube and the wire within the second double-lumen tube are each connected to an electrical connector at a proximal end of the double-lumen tubes. - View Dependent Claims (12, 13, 14)
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- 15. A vascular connector comprising a proximal fluid connection end, a distal fluid connection end, and an electrode configured to electrically connect a fluid-carrying lumen of the connector with a wire external to the vascular connector.
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20. An electrical circuit for measuring the resistance of a liquid between a first and second electrode, the first electrode connected to a first terminal of the electrical circuit, and the second electrode connected to a second terminal of the electrical circuit, comprising:
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a capacitor C1 connected on a first end to the first terminal and a capacitor C2 connected on a first end to the second terminal; a known reference resistance Rref connected on a first end to a second end of capacitor C1; switching means for connecting either; a) a first reference voltage V+ to a second end of Rref, and a lower second reference voltage V−
to a second end of C2 to form a first switch configuration or;b) the first reference voltage V+ to the second end of C2 and the lower second reference voltage V−
to the second end of Rref to form a second switch configuration; and
measuring means for measuring a voltage Vsense at the connection between C1 and Rref;
whereinthe electrical circuit is configured to determine the value of the resistance of the liquid based on the known reference resistance Rref and the observed voltage Vsense for each of the first and second switch configurations. - View Dependent Claims (21, 22, 23)
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Specification