| US 7,540,851 B2 | ||
| Method to control blood and filtrate flowing through an extracorporeal device | ||
| John J. O'Mahony, Hackensack, N.J. (US); Andrew Halpert, New York, N.Y. (US); Edward G. Rychlick, Riverdale, N.Y. (US); and Mark Gelfand, New York, N.Y. (US) | ||
| Assigned to CHF Solutions, Inc., Minnetonka, Minn. (US) | ||
| Filed on Jul. 27, 2004, as Appl. No. 10/899,079. | ||
| Application 10/899079 is a division of application No. 10/073855, filed on Feb. 14, 2002, granted, now 6,796,955. | ||
| Prior Publication US 2005/0004502 A1, Jan. 06, 2005 | ||
| Int. Cl. A61M 37/00 (2006.01); C02F 1/44 (2006.01) | ||
| U.S. Cl. 604—6.09 [604/6.1; 604/6.11; 604/5.04; 604/5.01; 210/645; 210/741; 422/44] | 4 Claims |
| 1. A method for controlling blood flow through an extracorporeal blood ultrafiltration circuit having a controller and a filtrate
pump comprising:
a. selecting a desired filtration rate for the ultrafiltration circuit to extract filtrate for an ultrafiltration treatment,
wherein the filtration rate is dependent on the filtrate pump;
b. withdrawing the blood through a needle or catheter inserted in a vein or artery of a vascular system of a patient and directing
the withdrawn blood into a withdrawal conduit of the extracorporeal circuit, filtering the blood to extract filtrates at the
desired filtration rate, introducing the filtered blood into an infusion conduit, and infusing the filtered blood into the
vascular system of the patient;
c. detecting a pressure of the blood in the withdrawal conduit or in the infusion conduit exceeding a predetermined threshold
pressure value, wherein the pressure is detected in the withdrawal conduit between the needle or catheter and a blood pump
coupled to the withdrawal conduit;
d. reducing a blood flow rate through the circuit in response to the detection of the pressure exceeding the threshold;
e. in connection with step (d) and in response to the detection of the pressure of the blood in the withdrawal conduit exceeding
the threshold, reducing a rate of filtrate extraction to a rate less than the desired filtration rate by the filtrate pump;
f. after step (e) increasing the blood flow rate through the circuit after determining that the pressure of the blood being
withdrawn or infused is within the threshold pressure value, and
g. increasing the filtration extraction rate after step (f), wherein the filtrate extraction rate is increased by the filtrate
pump.
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