US 11,992,589 B2
Measuring access flow rate by use of blood treatment machine
Jan Sternby, Lund (SE)
Assigned to GAMBRO LUNDIA AB, Lund (SE)
Appl. No. 16/338,658
Filed by GAMBRO LUNDIA AB, Lund (SE)
PCT Filed Sep. 27, 2017, PCT No. PCT/EP2017/074516
§ 371(c)(1), (2) Date Apr. 1, 2019,
PCT Pub. No. WO2018/065275, PCT Pub. Date Apr. 12, 2018.
Claims priority of application No. 1651296-4 (SE), filed on Oct. 3, 2016.
Prior Publication US 2020/0038572 A1, Feb. 6, 2020
Int. Cl. A61M 1/16 (2006.01); A61M 1/36 (2006.01)
CPC A61M 1/1615 (2014.02) [A61M 1/3604 (2014.02); A61M 1/36225 (2022.05); A61M 1/3656 (2014.02); A61M 1/3658 (2014.02); A61M 1/362264 (2022.05)] 25 Claims
OG exemplary drawing
 
1. A device for determining a fluid flow rate in a vascular access of a patient when connected to a blood treatment machine, said blood treatment machine comprising an extracorporeal blood flow circuit with first and second access devices for connection to the vascular access and having a blood pump operable to generate a flow of blood in the extracorporeal blood flow circuit from the first access device through a blood compartment of a dialyzer and to the second access device, and a treatment fluid flow circuit configured to generate a flow of treatment fluid through a treatment fluid compartment of the dialyzer, said treatment fluid compartment being separated from the blood compartment by a semi-permeable membrane, said device being configured to, during a measurement phase:
cause the blood treatment machine to switch between a first operating state and a second operating state, wherein the second operating state differs from the first operating state at least by a change of flow direction of the blood or the treatment fluid through the dialyzer;
acquire an output signal of at least one sensor in the blood treatment machine in the first and second operating states;
compute, based on the output signal, a measurement value of a comparison parameter that compares treatment efficiency in the first operating state to treatment efficiency in the second operating state;
obtain, for first and second sets of control values of operating parameters of the blood treatment machine in the first and second operating states, a current function that relates the comparison parameter to the fluid flow rate in the vascular access, the operating parameters including a cardiac output of the patient, a characteristic parameter of the dialyzer, a flow rate of the treatment fluid through the dialyzer, and a flow rate of the blood through the dialyzer; and
determine, based on the measurement value, an estimated value of the fluid flow rate in the vascular access so that the current function yields the measurement value.