US-12623009-B2 - Reducing biofilm build-up in a dialysate pathway by using ultrasonication and ionization

US12623009B2US 12623009 B2US12623009 B2US 12623009B2US-12623009-B2

Abstract

A hydraulic system and method are provided for breaking-up, dislodging, removing, and preventing the build-up of biofilm in a dialysate pathway of an extracorporeal blood treatment device. The dialysate pathway can include a dialyzer discharge line, a drain line, a dialyzer feed line, and a bypass system. At least one ultrasonic device can be positioned and configured to generate ultrasonic waves in the dialysate pathway and to propagate the ultrasonic waves along at least a portion of the dialysate pathway. The ultrasonic waves can be used to break-up biofilm. An ionizing electrode pair can also, or instead, be implemented to break-up, dislodge, remove, and prevent a build-up of biofilm. The system and method can particularly be implemented and useful in non-disposable portions of a hydraulic system of an extracorporeal blood treatment device.

Inventors

DAVID YUDS
Martin Crnkovich
Christian Schlaeper

Assignees

FRESENIUS MEDICAL CARE HOLDINGS, INC.
FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH

Dates

Publication Date: 20260512
Application Date: 20240710

Claims (20)

1 . A hydraulic system for an extracorporeal blood treatment device comprising: a dialysate pathway comprising a dialyzer discharge line configured to connect to an outlet of a dialyzer, and a drain line; at least one pump operationally configured to move a cleaning liquid through the dialysate pathway from the dialyzer discharge line to the drain line; at least one ultrasonic device configured to generate ultrasonic waves and positioned along the dialysate pathway so as to propagate the ultrasonic waves along at least a portion of the dialysate pathway; and a controller electrically connected to the at least one pump and to the at least one ultrasonic device, wherein the controller is configured to activate the at least one pump to direct a flow of cleaning liquid in the dialysate pathway from the dialyzer discharge line to the drain line, during a cleaning mode, and the controller is further configured to activate the at least one ultrasonic device during the cleaning mode.
2 . The hydraulic system for an extracorporeal blood treatment device, of claim 1 , wherein the controller is further configured to pause activation of the at least one pump while activating the at least one ultrasonic device, during the cleaning mode.
3 . The hydraulic system for an extracorporeal blood treatment device, of claim 1 , wherein the dialyzer discharge line comprises a connector end configured to be connected to the outlet of a dialyzer, and the hydraulic system for an extracorporeal blood treatment device further comprises an ionizing anode pair electrically connected to the controller, the ionizing anode pair including at least one ionizing anode situated in the dialyzer discharge line between the connector end and the drain line.
4 . The hydraulic system for an extracorporeal blood treatment device, of claim 3 , wherein the ionizing anode pair comprises a second anode situated in the drain line.
5 . The hydraulic system for an extracorporeal blood treatment device, of claim 3 , wherein the ionizing anode pair comprises a copper anode and a complimentary anode comprising at least one of an aluminum material and a ferrous material, wherein the copper anode and the complimentary anode are situated within the dialyzer discharge line and the controller is configured to supply current to the copper anode and to the complimentary anode during the cleaning mode.
6 . The hydraulic system for an extracorporeal blood treatment device, of claim 1 , further comprising a cleaning liquid within the dialysate pathway, wherein the at least one ultrasonic device is configured to generate ultrasonic waves in the dialysate pathway, to create low pressure volumes of the cleaning liquid in the dialysate pathway, and to create high pressure volumes of the cleaning liquid in the dialysate pathway, the low pressure volumes being of such low pressure as to generate gaseous bubbles, and the high pressure volumes being of such high pressure as to rupture the gaseous bubbles.
7 . The hydraulic system for an extracorporeal blood treatment device, of claim 1 , wherein the at least one ultrasonic device is configured to propagate ultrasonic waves at a sweep frequency.
8 . The hydraulic system for an extracorporeal blood treatment device, of claim 1 , wherein the dialyzer discharge line comprises a tubing, the at least one ultrasonic device comprises a collar that surrounds the tubing, and the at least one ultrasonic device propagates ultrasonic waves radially inwardly toward a center of the tubing.
9 . The hydraulic system for an extracorporeal blood treatment device, of claim 1 , wherein the at least one ultrasonic device further comprises an ultrasonic device coupled to the drain line.
10 . The hydraulic system for an extracorporeal blood treatment device, of claim 1 , wherein: the dialysate pathway further comprises a dialyzer feed line configured to connect to an inlet of a dialyzer, and a bypass system; the controller is also electrically connected to the at least one bypass system; the bypass system comprises a bypass line fluidly connecting the dialyzer feed line with the dialyzer discharge line; the bypass system comprises one or more valves configured to be actuated by the controller, during a cleaning mode, to direct a flow of liquid in the dialysate pathway from the dialyzer feed line to the dialyzer discharge line, without passing through a dialyzer; and the controller is configured to operate in preparation for the cleaning mode, by actuating the one or more valves such that liquid in the dialysate pathway is conveyed from the dialyzer feed line, through the bypass line, and into the dialyzer discharge line.
11 . The hydraulic system for an extracorporeal blood treatment device, of claim 10 , wherein the dialyzer feed line, the dialyzer discharge line, the bypass line, or a combination thereof, comprises a tubing, the at least one ultrasonic device comprises a collar that surrounds the tubing, and the at least one ultrasonic device propagates ultrasonic waves radially inwardly toward a center of the tubing.
12 . The hydraulic system for an extracorporeal blood treatment device, of claim 10 , wherein: the dialysate pathway further comprises a balancing device comprising a balancing chamber, a balancing feed line that leads to the balancing chamber and is configured to supply dialysate from a dialysate source into the balancing chamber, and a balancing discharge line that leads away from the balancing chamber and is configured to carry spent dialysate away from the balancing chamber and into the drain line; the dialyzer feed line extends from the balancing chamber and is configured to supply dialysate from the balancing chamber to a dialyzer during hemodialysis; the dialyzer discharge line extends to the balancing chamber and is configured to supply spent dialysate from the dialyzer into the balancing chamber during hemodialysis; and the at least one ultrasonic device is configured to generate ultrasonic waves in the balancing chamber during the cleaning mode.
13 . The hydraulic system for an extracorporeal blood treatment device, of claim 10 , further comprising a dialyzer having a dialyzer inlet and a dialyzer outlet, wherein the dialyzer feed line is connected to the dialyzer inlet, the dialyzer discharge line is connected to the dialyzer outlet, the one or more valves are configured to shut-off the bypass line during a treatment mode so that liquid in the dialysate pathway flows from the dialyzer feed line, into the dialyzer, through the dialyzer, out of the dialyzer outlet, and into the dialyzer discharge line, and the controller is configured to not activate the at least one ultrasonic device during the treatment mode.
14 . A method of operating the hydraulic device of claim 1 , the hydraulic system comprising the dialyzer discharge line and the drain line, the method comprising: disconnecting the dialyzer discharge line from a dialyzer; flowing a cleaning liquid from the dialyzer discharge line to the drain line; generating ultrasonic waves with an ultrasonic generator disposed along the dialyzer discharge line; and propagating the ultrasonic waves from the dialyzer discharge line toward the drain line during a cleaning mode of operation of the extracorporeal blood treatment device.
15 . The method of claim 14 , wherein the hydraulic system further comprises a dialyzer feed line and a bypass system, the bypass system comprises a bypass line fluidly connecting the dialyzer feed line with the dialyzer discharge line, the bypass system comprises one or more valves configured to direct a flow of liquid in the hydraulic system from the dialyzer feed line to the dialyzer discharge line, without passing through a dialyzer, and the method further comprises actuating the one or more valves such that liquid in the hydraulic system is conveyed from the dialyzer feed line, through the bypass line, and into the dialyzer discharge line without passing through a dialyzer.
16 . The method of claim 15 , wherein the hydraulic system further comprises a dialyzer having an inlet and an outlet, the dialyzer feed line is connected to the dialyzer inlet, the dialyzer discharge line is connected to the dialyzer outlet, and the method further comprises: flowing a dialysate through the dialyzer during a treatment mode, before the actuating of the one or more valves; and then performing the actuating of the one or more valves, during the cleaning mode, after the disconnecting of the dialyzer discharge line from the dialyzer, such that liquid in the hydraulic system is conveyed from the dialyzer feed line, through the bypass line, and into the dialyzer discharge line without passing through the dialyzer.
17 . The method of claim 16 , wherein during the treatment mode, the dialyzer feed line is supplied with a supply of the dialysate, and during the cleaning mode, the dialyzer feed line is supplied with a cleaning liquid.
18 . The method of claim 14 , further comprising: activating an ionizing anode pair during the cleaning mode, the ionizing anode pair comprising at least one ionizing anode situated in the dialyzer discharge line upstream of the drain line.
19 . The method of claim 18 , wherein: the generation of the ultrasonic waves is paused; and the ionizing anode pair is activated while the generation of ultrasonic waves is paused.
20 . The method of claim 14 , wherein the generating ultrasonic waves creates low pressure volumes of cleaning liquid within the hydraulic system, the generating ultrasonic waves creates high pressure volumes within the cleaning liquid in the hydraulic system, the low-pressure volumes generate gaseous bubbles in the cleaning liquid within the hydraulic system, and the high-pressure volumes rupture the gaseous bubbles in the cleaning liquid within the hydraulic system.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims the priority benefit of U.S. Provisional Patent Application No. 63/530,105, filed Aug. 1, 2023, which is incorporated herein in its entirety by reference. BACKGROUND OF THE INVENTION The present invention relates to reducing biofilm build-up in dialysis machines. The hydraulic system of some hemodialysis machines, for example, the 2008T hemodialysis machine available from Fresenius USA, Inc. of Concord, California, generates dialysate using three streams: an acid stream, a bicarbonate stream, and a stream of purified water. After fresh dialysate is mixed, it is pumped by a balancing chamber through a dialyzer wherein toxins from counter-current-flowing blood pass through a semi-permeable membrane. The dialysate effluent is then pumped as spent dialysate from the dialyzer and through a complementary half of the balancing chamber. The spent dialysate then passes through a heat exchanger and is drained out of the machine. Toxins and other organic matter pulled from the blood through the semi-permeable membrane and into the dialysate build up in the hydraulics of the machine over the course of the treatment and create biofilm. The hydraulics of the machine can include the entire dialysate side of the machine, that is, all of the plumbing and hydraulics involved with preparing fresh dialysate, draining spent dialysate, balancing fresh and spent dialysate, and circulating cleaning or sterilizing liquid through a dialysate pathway or dialysate circuit. Herein, a biofilm is defined as a collection of microorganisms (single or multiple species) that sticks to a surface. The biofilm can form a protective extracellular matrix or slime layer. The biofilm can attract other organisms and nutrients to enhance survival. The effects of biofilms on dialysis machines and dialysis machine operation is described, for example, in the article of J. Maltais entitled Biofilm, Where Does it Come From & Why is it Such a Problem, NANT 33rd Annual National Symposium, Mar. 23, 2016, which is incorporated herein in its entirety by reference. The article can be accessed at the following webpage: https://www.dialysistech.net/images/NANT2016Presentations/BioFilm.pdf. If the hydraulics of the machine are not properly disinfected, bacterial growth including in the form of biofilm can impede flow to the drain, damage components, corrode stainless steel, and lead to patient infections. The initial adherence of a biofilm foundation, referred to as Stage 2, can occur in just twelve minutes under certain conditions. After that, the organic structure continues to be built by sending out signals to attract more bacteria to the safe haven in the dialysate flow path. A germ- and endotoxin-free dialysate does not exclude the risks and hazards of bacteria and endotoxin discharge from biofilm developed in and on the fluid pathway tubing, chambers, and components. Biofilm can act as a reservoir for continuous contamination. Mishandling acid concentrates and bicarbonate concentrates, or contamination of the reverse osmosis system upstream of a water inlet, can result in biofilm growth throughout dialysis machine hydraulics. Practically all hydraulic systems for hemodialysis machines face the common problem of biofilm buildup. The industry response has always been chemical disinfection, heat disinfection, and replacing impacted components. In accordance with the report linked to https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5111172/sodium hypochlorite did not show good biofilm removal either at room temperature or when heated. Although it has been found that acetic acid is relatively more effective at biofilm removal when heated than at room temperature, long-term exposure to disinfectants such as acetic acid can deleteriously affect the piping material. Peracetic acid is effective at biofilm removal at both room temperature and when heated, but long-term exposure to acidic disinfectants such as peracetic acid can deleteriously affect dialysis machine hydraulics, including piping and chamber material. Yet another problem with biofilm build-up in dialysate lines and dialysis pathway components is the infiltration of biofilm during valve opening for heat disinfection. Biofilm components and bacteria can dislodge or break-off and be carried into the inflow side of a component, piping or tubing. Biofilm affects not only the lifetime of hydraulic components in the dialysate side of a hemodialysis machine but also the quality of dialysate used. SUMMARY OF THE PRESENT INVENTION A feature of the present invention is to optimize cleaning and disinfection procedures used for hemodialysis systems. A further feature of the present invention is to provide a method to detach and neutralize biofilm from hemodialysis machine hydraulics. A further feature of the present invention is to reduce the buildup of biofilm in a drain line by using ultrasonic transducers to create bubbles in spent dialysate. A furt