US 12,214,114 B2
Flow synchronization devices, methods, and systems
Jerome James, Vestavia, AL (US)
Assigned to NxStage Medical, Inc., Lawrence, MA (US)
Appl. No. 17/612,905
Filed by NxStage Medical, Inc., Lawrence, MA (US)
PCT Filed May 22, 2020, PCT No. PCT/US2020/034420
§ 371(c)(1), (2) Date Nov. 19, 2021,
PCT Pub. No. WO2020/237228, PCT Pub. Date Nov. 26, 2020.
Claims priority of provisional application 62/851,922, filed on May 23, 2019.
Prior Publication US 2022/0362448 A1, Nov. 17, 2022
Int. Cl. A61M 1/34 (2006.01); A61M 1/16 (2006.01)
CPC A61M 1/341 (2014.02) [A61M 1/1603 (2014.02); A61M 1/3441 (2013.01); A61M 2205/3334 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method of controlling pumps, that include an inlet peristaltic pump and an outlet peristaltic pump, in a hemofiltration system, comprising:
connecting the inlet peristaltic pump, by a connecting channel, in series with the outlet peristaltic pump;
pumping with the inlet peristaltic pump and the outlet peristaltic pump while measuring a pressure within the connecting channel between the inlet peristaltic pump and the outlet peristaltic pump until the measured pressure stabilizes within a predefined time interval;
varying an inlet peristaltic pump speed until the inlet peristaltic pump speed reaches a first value at which the pressure reaches a predefined target pressure P1;
increasing only the inlet peristaltic pump speed to a second value greater than the first value and recording a pressure P2 within the connecting channel corresponding to the second value of the inlet peristaltic pump speed;
after the increasing, decreasing only the inlet peristaltic pump speed to a third value smaller than the first value and recording a pressure P3 within the connecting channel corresponding to the third value of the inlet peristaltic pump speed;
fitting a line to at least points defined by the predefined target pressure P1 and the first value of the inlet peristaltic pump speed, pressure P2 and the second value of the inlet peristaltic pump speed, and pressure P3 and the third value of the inlet peristaltic pump speed;
deriving a parameter Icomp from a slope of the fitted line; and
using the parameter Icomp to control the inlet peristaltic pump speed.