Urease introduction system for replenishing urease in a sorbent cartridge
An apparatus and method for replenishing urease in a sorbent cartridge for use in sorbent dialysis. The system is configured to allow insertion of a urease pouch, injection of a urease solution, or addition of a urease cartridge, into a dialysis cabinet containing a dialysis flow loop. The urease can be dissolved and the resulting urease solution added to the sorbent cartridge in the flow loop to replenish the urease within the sorbent cartridge. The sorbent cartridge can also comprise other, rechargeable, sorbent materials for removing toxins other than urea from spent dialysate.
1. A dialysis flow loop, comprising:
a sorbent cartridge wherein the sorbent cartridge contains a urease-binding sorbent material;
a urease injection port positioned in a urease flow path fluidly connected to the dialysis flow loop, wherein the urease injection port is in fluid communication with the sorbent cartridge, wherein the urease flow path is positioned upstream of the sorbent cartridge, and wherein the urease injection port is adapted to receive a solution of urease;
a reservoir positioned between the urease injection port and the sorbent cartridge in the urease flow path; and
a control system, the control system programmed to meter at least a portion of urease in the reservoir into the sorbent cartridge.
2. The dialysis flow loop of claim 1 , further comprising a urease pump, wherein the urease pump is configured to move fluid from the urease injection port to the dialysis flow loop.
3. The dialysis flow loop of claim 1 , wherein the urease-binding sorbent material is either alumina, silica, or a combination thereof, and the urease injection port is adapted to receive a syringe.
4. The dialysis flow loop of claim 1 , wherein the sorbent cartridge further comprises one or more sorbent materials selected from the group consisting of activated carbon, hydrous zirconium oxide, zirconium phosphate and ion-exchange resin.
5. The dialysis flow loop of claim 1 , further comprising a urea detector positioned downstream of the alumina or silica.
6. A method of replenishing urease in a sorbent cartridge, comprising the step of:
injecting a urease solution into a urease injection port, wherein the urease injection port is in fluid communication with a reservoir; the reservoir in fluid communication with the sorbent cartridge, and wherein the urease injection port is positioned upstream of the sorbent cartridge; and
controlling a urease pump to meter a portion of the urease solution into the sorbent cartridge.
7. The method of claim 6 , further comprising the step of controlling a urease pump to pump the urease solution into the sorbent cartridge.
8. The method of claim 6 , further comprising the steps of:
determining an amount of urease in the sorbent cartridge by sensing the presence of one or more solutes in a fluid downstream of the sorbent cartridge; and
injecting the urease solution if the of the amount of urease in the sorbent cartridge is below a pre-set level.
9. The method of claim 8 , wherein the method is performed during a dialysis session.
10. A method of replenishing urease in a sorbent cartridge, comprising the steps of:
introducing urease into a urease compartment, wherein the urease compartment is in fluid communication with the sorbent cartridge;
introducing fluid to the urease compartment to dissolve the urease; and
metering a portion of a fluid having the dissolved urease to the sorbent cartridge.
11. The method of claim 10 , further comprising the step of introducing any one of a solid urease, a removable urease cartridge, and a urease pouch to the urease compartment.
12. The method of claim 10 , further comprising the step of using one or more pumps to add fluid to the urease compartment to introduce the fluid having the dissolved urease to the sorbent cartridge.