Access disconnection systems and methods
View Patent ↗Apparatuses, devices, systems and methods for detecting access disconnection are provided. In one embodiment, a medical fluid system includes (i) a medical fluid machine and (ii) a device operable with the medical fluid machine, the device configured to provide electrical contact with a medical fluid, the device including (a) a tube used during dialysis therapy through which the medical fluid can flow, and (b) a conductive element configured to self-sealingly pierce the tube, the conductive element having a first portion exposed to the medical fluid and a second portion external to the tube.
1. An extracorporeal blood system comprising:
an extracorporeal blood machine including an extracorporeal blood circuit;
an access device enabling the extracorporeal blood circuit to be connected to a patient;
a pair of electrical contacts configured to contact blood as the blood flows through the extracorporeal blood circuit; and
a controller configured to model a total impedance Z according to at least two lumped impedances including (i) a lumped impedance Z D due to components of the extracorporeal blood machine and (ii) a lumped impedance Z P due to access of the extracorporeal blood circuit to the patient.
2. The extracorporeal blood system of claim 1 , wherein Z P is due at least to the access device and tubing associated with the extracorporeal blood circuit.
3. The extracorporeal blood system of claim 1 , wherein Z D is due at least to a pump, dialyzer and drip chambers.
4. The extracorporeal blood system of claim 1 , wherein the controller is configured to assume Z P approaches infinity upon dislodgment of the access device from the patient, such that Z becomes at least substantially equal to Z D .
5. The extracorporeal blood system of claim 1 , wherein an electrical contact coupling device is coupled to the extracorporeal blood circuit.
6. The extracorporeal blood system of claim 5 , which includes a conductive device including a first member and a second member movably attached to the first member allowing for displacement of the first member and the second member into an open arrangement and a closed arrangement.
7. The extracorporeal blood system of claim 6 , wherein the conductive device includes a hinge attached to the first member and the second member at the end.
8. The extracorporeal blood system of claim 5 , wherein at least a portion of each of the first and second members is made of a material compatible with an electrical contact provide on the conductive device such that an effective electrical connection can be made.
9. The extracorporeal blood system of claim 1 , wherein the extracorporeal blood machine is of a type selected from the group consisting of:
hemodialysis, hemofiltration, hemodiafiltration and continuous renal replacement therapy.