Enhanced clearance in an artificial kidney incorporating a pulsatile pump
A continuous renal replacement therapy (CRRT) device is provided that weighs between 2 and 10 pounds. The CRRT device can be portable, mobile or completely worn on the person of the patient. Blood and dialysate are each pumped in a pulsed or pulsatile manner through a dialyzer such that a significant portion of the peak pulse of the blood flow coincides with a significant portion of a low pulse portion of the dialysate flow. An differential pressure between a dialysate inlet of the dialyzer and the blood inlet of the dialyzer periodically changes from a high differential pressure of between 70 and 120 mmHg for a first time period and a low differential pressure of between −10 and 10 mmHg for a second time period. The frequency of the high and low differential pressure cycle is between about 0.5 and 4 Hz.
1. A continuous renal replacement therapy (CRRT) device comprising:
a dual channel ventricle pulsatile pump including:
a blood pump channel for providing a pulsed blood flow, said pulsed blood flow being periodic such that each period comprises a high blood pressure portion having a first duration and a low blood pressure portion having a second duration, said first duration and said second duration having a duration ratio between about 3:4 and 4:3; and
a dialysate pump channel for providing a pulsed dialysate flow; said pulsed dialysate flow being periodic such that each period comprises a high dialysate pressure portion having said second duration and a low dialysate pressure portion having said first duration; wherein said high blood pressure portion and said low dialysate pressure portion occur, at least in part, during a first periodic time frame; and
a dialyzer comprising;
a blood inlet for receiving said pulsed blood flow;
a plurality of fibers, each fiber comprising a semi permeable membrane exterior and a lumen extending the length of the fiber, said lumen being for said pulsed blood flow to flow through;
a blood outlet for said pulsed blood flow to exit said dialyzer;
a dialysate inlet for receiving said pulsed dialysate flow;
a dialysate chamber, about said plurality of fibers, for said pulsed dialysate flow to flow through, said semi permeable membranes of said plurality of fibers being between each said lumen and said dialysate chamber; and
a dialysate outlet for said pulsed dialysate flow to exit said dialyzer;
wherein said blood pump channel, said dialysate channel and said dialyzer are configured to establish a peak Trans Membrane Pressure (TMP) across said semi permeable membranes of
wherein said blood pump channel, said dialysate channel and said dialyzer are configured to establish a peak Trans Membrane Pressure (TMP) across said semi permeable membranes of said plurality of fibers and between said pulsed blood flow in said lumens and said pulsed dialysate flow in said dialysate chamber, said peak TMP occurring during said first periodic time frame, said peak TMP being between about 70 mmHg and 120 mmHg.
2. The CRRT device of claim 1 , wherein said low blood pressure portion and said high dialysate pressure portion both occur, at least in part, during a second periodic time frame, and wherein said blood pump channel, said dialysate channel and said dialyzer are configured to establish a minimum TMP across said semi permeable membranes of said plurality of fibers and between said pulsed blood flow in said lumens and said pulsed dialysate flow in said dialysate chamber, and wherein said minimum TMP occurs during said second periodic time frame, said minimum TMP being between about 10 mmHg and −10 mmHg.
3. The CRRT device of claim 2 , wherein the combination of said peak TMP that occurs during said first periodic time frame and said minimum TMP that occurs during said second periodic time frame inhibit clogging of said lumens and said semi permeable membranes.
4. The CRRT device of claim 1 , wherein said blood pump channel and said dialysate pump channel are actuated by a same mechanical mechanism.
5. The CRRT device of claim 1 , wherein said CRRT device is completely wearable on a patient.
6. The CRRT device of claim 1 , wherein said blood pump channel provides said pulsed blood flow with a periodic flow rate of between 0.5 and 4 Hz and wherein said dialysate pump channel provides a pulsed dialysate flow with said periodic flow rate.
7. The CRRT device of claim 1 , wherein said pulsed blood flow is a pulsatile blood flow.
8. The CRRT device of claim 1 , wherein said pulsed blood flow a pulsatile blood flow.