CN116234590A - Dialysis systems and methods - Google Patents

Abstract

Dialysis systems and methods are described that can include a number of features. The described dialysis system can provide dialysis treatment to a patient in a comfortable environment of the patient's own home. The dialysis system can be configured to prepare purified water in real time from a tap water source for use in producing a dialysate solution. The dialysis system described also includes features that facilitate the patient's self-management of the treatment.

Description

Dialysis systems and methods

Cross References to Related Applications

This application claims the benefit of priority to U.S. Provisional Application No. 63/061,623, filed August 5, 2020, which is hereby incorporated by reference in its entirety.

incorporated by reference

All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. to the same extent.

field

The present disclosure generally relates to dialysis systems. More specifically, the present disclosure relates to the delivery of replacement fluids, saline, or other diluting fluids into blood flow paths. The present disclosure is particularly applicable to longer periods of therapy, increasing user convenience through automation, and reducing nuisance alarms associated with automated saline delivery.

background

Currently, there are hundreds of thousands of patients with end-stage renal disease in the United States. Most patients require dialysis to survive. Many patients receive dialysis treatment at a dialysis center, which can create a demanding, restrictive and tiring schedule for the patient. Patients on dialysis at the center typically have to go to the center at least three times a week and sit in a chair for three to four hours each time, during which time toxins and excess fluid are filtered from their blood. After treatment, patients must wait for the needle site to stop bleeding and blood pressure to return to normal, which takes more time away from other, more meaningful activities in their daily lives. Additionally, patients at the center must adhere to a strict schedule, as a typical center treats patients on three to five shifts a day. As a result, many people on dialysis three times a week complain of feeling exhausted for at least a few hours after a session.

Many dialysis systems on the market require a lot of input and attention from the technician before, during and after dialysis treatment. Prior to treatment, technicians typically need to manually install patient blood tubing sets onto the dialysis system, connect the tubing sets to the patient and the dialyzer, and manually prime the tubing sets to drain the tubing sets prior to treatment air. During treatment, technicians typically need to monitor venous pressure and fluid levels, and administer large doses of saline and/or heparin to the patient. After treatment, the technician is usually required to return the blood in the tubing set to the patient and drain the dialysis system. The inefficiency of most dialysis systems and the large number of technicians involved in the process make it difficult for patients to receive dialysis outside of large treatment centers.

Given the demanding nature of in-center dialysis, many patients have turned to home dialysis as an option. Home dialysis offers patients flexibility in scheduling because home dialysis allows patients to choose the time of treatment to allow time for other activities, such as going to work or caring for family members. Unfortunately, current dialysis systems are often not suitable for use in the patient's home. One reason for this is that current systems are too large and unwieldy to fit in the average home. Current dialysis systems are also energy inefficient because they use a lot of energy to heat large volumes of water for proper use. Although some home dialysis systems are available, they are often difficult to install and use. Therefore, most dialysis treatments for chronically ill patients are performed in dialysis centers.

Hemodialysis can also be performed in an acute hospital setting, for current dialysis patients who are hospitalized, or for patients with acute kidney injury. In these care settings, typically hospital wards, water of sufficient purity to produce dialysate is not readily available. As a result, hemodialysis machines in acute situations rely on large quantities of premixed dialysate, often in large bags, and are cumbersome for staff to handle. Alternatively, the hemodialysis machine can be connected to a portable RO (reverse osmosis) machine or other similar water purification device. This introduces another separate piece of equipment that must be managed, transported and sterilized.

Overview of the Disclosure

A method of improving the performance of a dialysis tubing comprising an arterial line and further comprising a fluid delivery line connecting a fluid source to the dialysis tubing is provided, the method comprising the steps of: occluding the arterial line of the dialysis tubing; A clamping mechanism engaging the fluid delivery line; regulating a pump speed of a blood pump engaged with the dialysis tubing to increase fluid pressure within the dialysis tubing; and delivering fluid from a fluid source through the fluid delivery line into the dialysis tubing.

In some embodiments, modulating the pump speed of the blood pump includes increasing the flow rate of the blood pump from a first flow rate to a second flow rate.

In other embodiments, modulating the pump speed of the blood pump includes decreasing the flow rate of the blood pump from the first flow rate to the second flow rate.

In one embodiment, modulating the pump speed of the blood pump includes pulsating the flow rate of the blood pump.

In some examples, regulating the pump rate of the blood pump includes decreasing the flow rate of the blood pump from about 320 ml/min to about 180 ml/min.

In another embodiment, the method further includes automatically scheduling the occluding step, the opening step, and the modulating step to occur periodically during the dialysis treatment.

In one embodiment, after opening or releasing the clamping mechanism, a portion of the fluid delivery line remains occluded due to prior extended clamping of the fluid delivery line.

In another embodiment, after opening or releasing the clamping mechanism, a portion of the fluid delivery line remains partially occluded due to the clamping of the forward extension of the fluid delivery line.

In one example, the method further includes the steps of: unoccluding the arterial line; closing or compressing a clamping mechanism engaged with the fluid delivery line; and initiating dialysis therapy.

A dialysis system is provided, comprising a fluid source; a dialysis tubing set comprising at least an arterial line, a blood pump portion, and a fluid delivery line connecting the fluid source to the dialysis tubing set; a blood pump configured to communicate with the dialysis tubing set a blood pump partially engaged; a first clamping mechanism configured to engage the arterial line; a second clamping mechanism configured to engage the fluid delivery line; and an electronic controller configured to control the blood operation of the pump, the first clamping mechanism, and the second clamping mechanism, wherein, during the priming sequence, the electronic controller is configured to: close or occlude the first clamping mechanism; open or unocclude the second clamping mechanism ; regulating the pump speed of the blood pump to increase the fluid pressure within the dialysis tubing set and delivering fluid from the fluid source through the fluid delivery line into the dialysis tubing.

In one embodiment, the electronic controller is configured to regulate the pump speed of the blood pump by increasing the flow rate of the blood pump from the first flow rate to the second flow rate.

In another embodiment, the electronic controller is configured to regulate the pump speed of the blood pump by decreasing the flow rate of the blood pump from the first flow rate to the second flow rate.

In some examples, the electronic controller is configured to regulate the pump speed of the blood pump by pulsing the flow rate of the blood pump.

In one embodiment, the electronic controller is configured to regulate the pump rate of the blood pump, including reducing the flow rate of the blood pump from about 320 ml/min to about 180 ml/min.

In another embodiment, the controller is configured to automatically perform the closing step, opening step and regulating step periodically during the dialysis treatment.

In some embodiments, a portion of the fluid delivery line remains occluded due to the clamping of the forward extension of the fluid delivery line after the clamping mechanism is opened or released.

In one embodiment, after opening or releasing the clamping mechanism, a portion of the fluid delivery line remains partially occluded due to the clamping of the forward extension of the fluid delivery line.

In some embodiments, the electronic controller is further configured to: unocclude the arterial line; close or compress a pinch mechanism engaged with the fluid delivery line; and initiate dialysis treatment.

A method of increasing the performance of a dialyzer during a dialysis treatment is provided, comprising the steps of: initiating the dialysis treatment; detecting a pressure difference between a blood side of the dialyzer and a dialysate side of the dialyzer; if the pressure difference exceeds a predetermined threshold, Then: occlude the arterial line of the dialysis tubing; open or release the clamping mechanism engaged with the fluid delivery line; regulate the pump speed of the blood pump engaged with the dialysis tubing to increase the fluid pressure in the dialysis tubing; and, pass the fluid from the fluid source through the A fluid delivery line delivers into the dialysis tubing.

In some embodiments, modulating the pump speed of the blood pump includes increasing the flow rate of the blood pump from a first flow rate to a second flow rate.

In other embodiments, modulating the pump speed of the blood pump includes decreasing the flow rate of the blood pump from the first flow rate to the second flow rate.

In one embodiment, modulating the pump speed of the blood pump includes pulsating the flow rate of the blood pump.

A method of returning blood to a patient following dialysis treatment using a dialysis system comprising a fluid delivery line connecting a fluid receptacle to a dialysis tubing set comprises the steps of: opening or releasing the clamping mechanism engaged with the fluid delivery line; backfiltering the dialysate through the dialyzer of the dialysis system, into the dialysis tubing set, and into the fluid receiver via the fluid delivery line; performing dialysis therapy with the dialysis system, comprising drawing blood into the dialysis tubing set; and returning the blood to the patient with back-filtered dialysate in the fluid receiver.

In some embodiments, backfiltering the dialysate through the dialyzer further includes controlling a first dialysate pump upstream of the dialyzer to have a faster pump speed than a second dialysate pump downstream of the dialyzer.

Brief description of the drawings

The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by referring to the following detailed description, which sets forth illustrative embodiments that utilize the principles of the invention, and the accompanying drawings, in which:

Figure 1 shows an embodiment of a dialysis system.

Figure 2 shows an embodiment of a water purification system of a dialysis system.

Figure 3 illustrates one embodiment of a dialysis delivery system of a dialysis system.

Figure 4 shows the connection between the saline source, the blood circuit and the patient.

Figure 5A shows a method of delivering saline with a dialysis system.

Figure 5B is a graph showing blood pump flow rate and arterial line pressure during saline delivery.

Figure 6A shows a method of delivering saline with a dialysis system.

6B is a graph showing blood pump flow rate and arterial line pressure during saline delivery.

7 and 8 illustrate methods of delivering saline with a dialysis system.

9A-9B are schematic diagrams of one embodiment of a dialysis system with a rinseback configuration.

Figure 10 is a method and flowchart of returning blood to a patient using back-filtered dialysate after dialysis treatment.

A detailed description

The present disclosure describes systems, devices, and methods related to dialysis treatment, including dialysis systems that are easy to use and include automation features that eliminate or reduce the need for technician involvement during dialysis treatment. In some embodiments, the dialysis system may be a home dialysis system. Embodiments of dialysis systems may include various features to automate and improve the performance, efficiency, and safety of dialysis treatments.

In some embodiments, a dialysis system is described that can provide acute and chronic dialysis treatment to a user. The system may include a water purification system configured to prepare water for dialysis treatment in real time using an available water source, and a dialysis delivery system configured to prepare dialysate for dialysis treatment. A dialysis system may include a disposable cartridge and tubing set for connection to a user during a dialysis treatment for obtaining and delivering blood from the user.

FIG. 1 illustrates one embodiment of a dialysis system 100 configured to provide dialysis treatment to a user in a clinical or non-clinical setting, such as the user's home. Dialysis system 100 may include water purification system 102 and dialysis delivery system 104 disposed within housing 106 . Water purification system 102 may be configured to purify a water source in real time for dialysis treatment. For example, a water purification system can be connected to a residential water source (eg, tap water) and prepare pasteurized water in real time. The pasteurized water can then be used in dialysis treatment (eg, with a dialysis delivery system) without the need for heating and cooling of the bulk water typically associated with water purification methods.

Dialysis system 100 may also include a cassette and/or tubing set 120 that may be detachably coupled to housing 106 of the system. The cassette may include a patient tubing set attached to a manager, which will be described in more detail below. The cassette and tubing set (which may be a sterile, disposable, single-use component) is configured for connection to the dialysis system prior to treatment. This connection enables proper alignment of the cassette, tubing set and corresponding components between the dialysis system prior to dialysis treatment. For example, when the cassette is coupled to the dialysis system, the tubing set is automatically associated with one or more pumps (eg, peristaltic pumps), clamps, and sensors for drawing and pumping the user's blood through the tubing set. The tubing set can also be associated with the dialysis system's saline source for automatic perfusion and air removal prior to treatment. In some embodiments, the saline source can be any source of replacement fluid commonly used in dialysis treatment, including but not limited to saline, sterile isotonic fluid, blood, donor plasma, and the like. In some embodiments, the cassette and tubing set can be connected to the dialyzer 126 of the dialysis system. In other embodiments, the cassette and tubing set may include a built-in dialyzer pre-attached to the tubing set. A user or patient can interact with the dialysis system via a user interface 113 that includes a display.

2-3 illustrate a water purification system 102 and a dialysis delivery system 104 of one embodiment of a dialysis system 100, respectively. For ease of explanation, the two systems are shown and described separately, but it should be understood that both systems may be included in a single housing 106 of the dialysis system. Figure 2 illustrates one embodiment of a water purification system 102 contained within a housing 106, which may include a front door 105 (shown in an open position). Front door 105 may provide access to features associated with the water purification system, such as one or more filters, including sediment filter 108 , carbon filter 110 , and reverse osmosis (RO) filter 112 . The filter may be configured to assist in the purification of water from a water source (eg, tap water) in fluid communication with the water purification system 102 . The water purification system may also include heating and cooling elements (including heat exchangers) configured to pasteurize and control the temperature of fluid in the system, as will be described in more detail below. The system may optionally include a chlorine sample port 195 to provide a sample of the fluid for measuring chlorine levels.

In FIG. 3 , dialysis delivery system 104 contained within housing 106 may include upper cover 109 and front door 111 , both of which are shown in an open position. Upper cover 109 can be opened to allow access to various features of the dialysis system, such as user interface 113 (eg, a computing device including electronic controls and a display such as a touch screen) and dialysate container 117 . Front door 111 can be opened and closed to allow access to front panel 210, which can include various features configured to interact with cassette 120 and its associated tubing set, including being configured to couple cassette 120 to dialysis system 100. alignment and attachment features. The dialyzer 126 may be mounted in the front door 111 or on the front panel and may include lines or ports connecting the dialyzer to the prepared dialysate and to the tubing set of the cassette.

In some embodiments, the dialysis system 100 may also include a blood pressure cuff to provide real-time monitoring of the user's blood pressure. The system (ie, the electronic controller of the system) can be configured to monitor a user's blood pressure during dialysis treatment. If the user's blood pressure drops below a threshold (eg, a blood pressure threshold indicating hypotonicity for the user), the system can alert the user with a low blood pressure alert, and dialysis treatment can be stopped. In the event the user ignores a configurable number of low blood pressure alerts from the system, the system can be configured to automatically stop dialysis treatment, at which point the system can notify the user that the user's blood (blood remaining in the tubing set and dialyzer) needs to be removed Return to the user's body. For example, the system can be preprogrammed to automatically stop therapy if the user ignores three low blood pressure alerts. In other embodiments, the system may administer a bolus of saline to the user to restore the user's fluid level before resuming dialysis treatment. During removal of ultrafiltered fluid, the amount of saline delivered to the patient can be tracked and calculated.

The dialysis delivery system 104 of FIG. 3 may be configured to automatically prepare dialysate fluid from purified water supplied by the water purification system 102 of FIG. 2 . In addition, the dialysis delivery system may degas the purified water, proportioned and mixed in the acid and bicarbonate concentrate from the dialysate container 117 . The resulting dialysate fluid can be passed through one or more ultrafilters (described below) to ensure that the dialysate fluid meets certain regulatory limits for microbial and endotoxin contaminants.

Dialysis may be performed in dialysis delivery system 104 of dialysis system 100 by passing a user's blood and dialysate through dialyzer 126 . Dialysis system 100 may include an electronic controller configured to manage various flow control devices and features for regulating the flow of dialysate and blood into and out of the dialyzer in order to achieve different types of dialysis, including hemodialysis , ultrafiltration and hemodiafiltration.

A dialysis system may include a connection between a saline source or other hemocompatible fluid and an extracorporeal blood circuit. This fluid can be used in many applications such as perfusing the circuit prior to therapy, delivering bolus to improve hemodynamic stability, delivering periodic flushes to alleviate circuit coagulation, replacing fluid for high convective therapy, and when blood Chaser fluid when returning at the end of treatment. Typically, such a saline source may be a bag pierced by a spike attached to a branch line leading into the extracorporeal blood circuit. Flow from a saline source can be controlled by pinching and loosening a physical clamp or an electronically controlled pinch valve. Access to a part of the blood circuit that is under negative pressure (for example upstream of a blood pump in the circuit) is advantageous so that when the line is released, the negative pressure will facilitate flow from the saline source.

The present disclosure provides methods and systems configured to precisely and accurately meter the flow of fluid from a saline source. In one configuration, referring to FIG. 4 , a dialysis system such as the system 100 described above may include a saline source 401 configured to connect to a tubing set 420 upstream of a blood pump 403 . As shown, a dialyzer 426 may also be connected to the tubing set. Tubing set 420 may include saline line 405 , arterial line 407 and venous line 409 . The tubing set can be configured with one or more pinch clamps such as saline clamp 411 (also known as "pre-pump saline pinch valve") and arterial clamp 413 (also known as "arterial pinch valve") ) engagement. It should be understood that other mechanisms may be used to close/occlude and open/unocclude the tube stack. Generally, clamps or pinch valves as referred to herein include any mechanism that engages a tubing stack to open or close fluid flow through the tubing stack.

In one embodiment, the saline clamp 411 can be controlled to be loosened (eg, the pre-pump saline pinch valve is opened), and the blood pump can be configured to run or operate in a normal operating mode. Although the total output of the blood pump is known, the blood pump draws an indeterminate portion of its flow from the patient and a second indeterminate portion of its flow from the saline source. One technique for metering the amount of saline drawn into the tubing set is to simultaneously occlude the arterial line emerging from the patient (with the arterial clamp 413) and unocclude the saline line to deliver saline (by opening the saline clamp 411 ). For example, the pinch valve can be computer controlled, so the opening and/or closing of clamps 511 and 413 can be effected using the system's electronic controller. By doing so, the overall input and output of the blood pump is switched from the patient to the saline source, allowing accurate metering of the saline delivered. In normal operation during therapy, the arterial clamp is open to allow flow and the saline clamp is closed to prevent saline from entering the circuit.

Tubing, including blood circuit tubing sets, is usually composed of polymers which exhibit changes in properties over time, especially under load. The ability of saline line tubing to maintain occlusion under high forces during most treatments becomes more important during longer periods of treatment. Typical intermittent hemodialysis (IHD) treatment may last four hours; however, partial intermittent renal replacement therapy (PIRRT), slow, low-efficiency dialysis (SLED) and continuous renal replacement therapy (CRRT) treatment may last 24 hours or longer. When the tube stack is held in an occluded state by a compressive force, the tube stack may undergo compression deformation, or exhibit stress relaxation behavior. When the compressive force is removed to unocclude the tube, the degree to which the material properties change may affect the time it takes for the tube to open, or whether the tube opens completely. This situation is exacerbated if one side of the previous occlusion point is under negative pressure (for example upstream of a blood pump), which will tend to force the walls of the tube to remain closed to each other.

If the saline line remains occluded despite removal of the compressive force (eg, by opening the pinch valve), no saline can flow. If the arterial line remains unoccluded when an attempt is made to open the saline line, no saline is delivered. If the arterial line is occluded when trying to open the saline line, a very low negative pressure will be generated as the pump tries to pump through both occluded lines. This condition can be detected by the machine, which can lead to unnecessary alerts that interrupt workflow or terminate treatment.

A process flow diagram and exemplary curves of arterial pressure for a tube that has been occluded for 16 hours, showing a sharp downward spike, are provided in FIGS. 5A and 5B , respectively. For example, referring to FIG. 5A , a method includes receiving a "deliver saline" command at step 502 , which initiates closing of the arterial pinch valve and opening of the pre-pump saline pinch valve. At steps 504 and 506, the arterial pinch valve may be closed and the pre-pump saline pinch valve may be opened. Next, at step 508, saline is delivered into the blood circuit via the blood pump. When the desired volume of saline has been drawn into the blood circuit, the arterial pinch valve may be opened at step 510 and the pre-pump saline pinch valve may be closed at step 512 . Finally, normal treatment resumes at step 514 .

In order to improve the performance of long-term occluded tubes, a new procedure is introduced in which a temporary modulation of the blood pump is introduced after the saline valve is opened and the arterial pinch valve is closed. This regulation may include slowing, stopping, reversing or pulsing the blood pump. By doing so, the kinetic energy of the fluid flowing through the blood line must be arrested or absorbed, causing the flow to stop. This creates a "water hammer" effect, causing a dramatic rise in pressure. This rise in pressure propagates to the occlusion in the saline line, which helps force the occlusion open. An improved flowchart and exemplary pressure curves are provided in FIGS. 6A-6B . Referring to FIG. 6A , the novel method of the present disclosure includes receiving a “deliver saline” command at step 602 , which initiates closing of the arterial pinch valve at step 604 and opening of the pre-pump saline pinch valve at step 606 . Next, at step 607, the blood pump rate is varied (eg, increased or decreased from a "normal" operating rate, or alternatively modulated or pulsed). Next, at step 608, saline is delivered into the blood circuit via the blood pump. When the desired volume of saline has been drawn into the blood circuit, the arterial pinch valve may be opened at step 610 and the pre-pump saline pinch valve may be closed at step 612 . Finally, normal treatment resumes at step 614 . Changing the blood pump rate may include, for example, temporarily slowing the blood pump rate from a first flow rate (eg, 320ml/min) to a second flow rate (eg, 180ml/min). This eliminates the downward spike shown in Figure 5B and instead introduces an upward spike in arterial pressure. In other embodiments, the blood pump rate may be temporarily increased between the first flow rate and the second flow rate. As noted above, in some embodiments, the speed of the blood pump may be rapidly varied or "pulsed" during this step.

A related aspect of the present disclosure is the ability to automatically schedule saline delivery flushes. Referring to the flowchart of FIG. 7, at step 702, a user of the dialysis system may first set a net desired fluid removal rate or target for the patient. Next, at step 704 , the user may specify a desired saline flush interval and volume of saline to be delivered, as well as a desired duration of therapy (step 706 ), and therapy may be initiated at step 708 . During treatment, the flushing process of Figure 6A will occur periodically. This can help alleviate circuit coagulation, allow higher fluid removal to enhance convective clearance, or be used as a dilution indicator to perform physiological measurements (such as blood volume, access recirculation, or access flow). For example, still referring to FIG. 7, at step 710, the system may check whether the treatment duration of step 706 has elapsed. If not, then at step 712 the system will check whether the flush interval of step 704 has elapsed. When the interval elapses, the system may deliver saline into the tubing set as step 714 using the method shown in FIG. 6A. At step 716, the system may add ultrafiltration to remove the saline flush from step 714 from the treatment and maintain a net fluid removal target.

Users can also set a desired interval before the end of treatment when no saline flush occurs. If the desired frequency and volume of saline flushes are known, as well as the expected duration of treatment, the total saline required can be calculated. Assuming each saline container (eg, 1 liter saline bag) has a known volume, the system will be able to notify the user prior to treatment to collect the required number of saline containers to complete the desired saline flush cadence. Alternatively, the system may display the total saline volume required, which the user may provide in a single or multiple larger containers. The system can further determine the unused volume in the last saline container to be used (minus the volume required for blood return) and recommend increasing the volume and/or frequency such that the unused volume is used for extra flushing without being wasted. Alternatively, the total fluid removal target may effectively increase the volume close to the unused volume beyond the fluid removal target. At the end of treatment, the system can then inject the unused volume to achieve the initial fluid removal goal.

Still referring to FIG. 7 , at step 716 the dialysis system can also be configured to automatically increase the patient's fluid removal rate in order to remove the additional fluid added by these saline flushes over time. Briefly, this can be adjusted to remove only the excess volume created by the saline flush in order to achieve the desired net fluid removal target. This reduces the mental burden on the user of calculating the amount of saline to infuse and manually adjusting the amount of fluid removal to account for this. Dilution of total blood volume caused by saline irrigation can also be used to perform measurements of available blood volume. The fluid removal rate can also be adjusted based on this measurement.

In another embodiment, referring to the flowchart of FIG. 8, the flushing interval is not predetermined, but triggered based on measurements of various parameters. Referring to the flowchart of FIG. 8, at step 802, a user of the dialysis system may first set a net desired fluid removal rate or target for the patient. Next, at step 804 , the user may specify a desired saline flush interval and volume of saline to be delivered, as well as a desired duration of therapy (step 806 ), and therapy may be initiated at step 808 . For example, still referring to FIG. 8, at step 810, the system may check whether the treatment duration of step 806 has elapsed. If not, then at step 812 the system can measure parameters associated with the dialysis system, dialyzer, or dialysis treatment. In one embodiment, the parameters may include transmembrane pressure. For example, transmembrane pressure is defined as the pressure difference between the dialysate side of the dialyzer and the blood side of the dialyzer. If coagulation occurs within the dialyzer, the resistance to flow between the two compartments increases and thus the transmembrane pressure increases. For high-flux dialyzers, even at high ultrafiltration rates, there is usually very low transmembrane pressure unless there is some degree of coagulation. If at step 814 it is detected that the transmembrane pressure meets a certain threshold, the dialysis system may automatically initiate a saline flush at step 816 . At step 818, as discussed above, ultrafiltration may be added to remove flush volume during treatment and maintain a net fluid removal target.

Other parameters such as the slope of the transmembrane pressure curve can be measured or taken into account, which can also be used to regulate factors such as saline flush volume or delivery flow rate. These can also be regulated by the user. Other measurements could be considered, for example a relatively small volume of "scout" flush could be released periodically in order to measure the transit time of the dilution between two sensors placed in the circuit before and after the dialyzer. If intradialyzer coagulation is detected, the volume within the fiber is reduced, which results in a reduction in the transit time of the dilution relative to a baseline measurement taken earlier, or when there is no coagulation. The coagulation cascade has also been reported to cause changes in blood conductivity. These signals can also be used to trigger saline flushes. Alternatively, when any such measured threshold is reached, the system may notify the user and recommend a saline flush, which must be confirmed by the user, rather than automatically triggering a saline flush.

Further feedback can be built into this measurement-based approach for saline flush control. For example, a saline flush could be initiated once the transmembrane pressure reaches a certain threshold. After flushing, the transmembrane pressure is assessed again, and if the measurement is still above this threshold or a different threshold, another flush is initiated. These flushes can be repeated until the desired transmembrane pressure value is reached. The system can be configured to notify the user if the maximum volume or number of flushes fails to reduce the transmembrane pressure to the desired volume.

As described herein, the additional step of regulating the rate of the blood pump may advantageously help open saline lines that may have undergone compression set during prolonged treatment. Additionally, the dialysis system can be configured to automatically schedule saline flushes and increase fluid removal rates to account for excess delivered fluid. In some embodiments, the saline flush interval is dependent on measured parameters from the dialysis system (eg, measured pressure, flow rate, fluid parameters, etc.).

The methods and systems described herein provide less nuisance alarms and precise saline delivery. Furthermore, the methods and systems described herein increase the convenience of user control of circuit coagulation, or add convective clearance and/or other things, or perform physiological measurements without the need for manual flushing and adjustment of fluid removal targets.

For circuit coagulation, current anticoagulant strategies involve systemic anticoagulants (such as heparin or citrate), which can lead to bleeding or severe electrolyte changes (calcium), metabolic alkalosis, or accumulation of substances if the patient cannot metabolize them effectively Increased risk. This was overcome using a scheduled saline flush as described herein.

One problem that arises is when the machine malfunctions during treatment. Given that the dialysate fluid is generated in real time and is used to return the patient's blood in contrast to a filled saline bag, since the fluid is only generated "on demand," such a failure could prevent the patient's blood from being able to return. Other functions, such as priming of lines and delivery of fluid boluses, are not affected since they are only required when the machine is functioning normally. It would therefore be desirable to provide a device that returns the patient's blood at the end of treatment that is functionally independent of whether the wider robotic system is still functioning, while taking advantage of the logistical simplicity of not requiring saline bags.

In one configuration, referring to FIG. 9A , a dialysis system, such as system 100 described above, can include a backflush fluid source 901 configured to connect to tubing set 920 upstream of blood pump 903 . As shown, a dialyzer 926 may also be connected to the tubing set. Tubing set 920 may include saline line 905 , arterial line 907 and venous line 909 . The tubing set can be configured to engage with one or more pinch clamps, such as saline clamp 911 (also referred to as "pre-pump saline pinch valve") and arterial clamp 913 (also referred to as "arterial pinch valve"). ).

Referring to FIG. 9B , the dialysis system may also include a plurality of dialysate pumps 915 and 917 disposed on the dialysate side of the dialyzer 926 with a tubing set 920 located on the "blood side" of the dialyzer. relatively. One of the dialysate pumps can be arranged upstream of the dialyzer, and one of the dialysate pumps can be arranged downstream of the dialyzer. The pump speed of the dialysate pump can be controlled to manage the flow of dialysate through the dialyzer and to control the rate of ultrafiltration during dialysis treatment. For example, downstream pump 915 may be controlled to a faster pump speed than upstream pump 917 in order to remove fluid from the patient.

As noted above, the backflush fluid source 901, similar to a saline source, is preferably connected to the blood circuit with an automatic control valve. However, unlike previous solutions, this recoil fluid source is shipped empty. In one embodiment, this source of backflush fluid may be pre-connected to the blood tubing set, unlike saline bags which must be accessed through a "tip" connector (which introduces the risk of contamination and/or user injury). In some embodiments, the preferred capacity of the bag is about 500 mL, and at least 250 mL, which is typically the actual volume of fluid required for backflushing.

As shown in Figure 9A, the tubing set is connected to the dialysate circuit through a dialyzer 926 comprising a semipermeable membrane (allowing blood filtration) separating the two compartments. In preferred embodiments, the system's dialysate is generated in real time, and preferably from decomposed powder or liquid components. The dialysis system may include a dialysate mixing system that includes a variable ratio capability. For example, lower concentrations of bicarbonate buffer can be added to the dialysate during perfusion to more closely mimic the composition of saline. In some embodiments, the dialysate circuit is capable of removing fluid from the blood circuit (excess fluid needs to be removed from the patient during normal therapy) and pushing fluid into the blood circuit for perfusion, boluses and recoil.

As part of the perfusion sequence, the dialysis system is configured to back-filter dialysate through the dialyzer into the blood circuit. The upstream pump 917 can be controlled to a faster pump speed than the downstream pump 915 in order to backfilter the dialysate through the dialyzer. A valve to the backflush fluid source 901 (eg, saline valve 911 ) can be controlled to open, and the backflush fluid bag will fill with back-filtered perfusate. Once a predetermined amount of fluid has been pumped into the backflush fluid source, valve 911 may be controlled to close or occlude the saline line and remain closed until backflush is ready to begin. This way, if the machine's dialysate circuit fails, blood return can still be performed using the pre-filled fluid in the backflush bag. It is sometimes necessary to discard the initial volume of priming fluid that contacted the dialyzer in order to flush out the sterilization residual chemicals. In this case, at the start of priming, the valve 911 to the source of backflush fluid is closed at the start of priming, and the blood circuit is primed without filling the backflush bag. The blood circuit perfusion fluid is then discarded and replaced with fresh back-filtered dialysate. At this point, following the priming discard sequence, the valve to the backflush bag can be opened and the bag can be filled with backflush dialysate fluid.

10 is a flowchart describing a method of using back-filtered dialysate in a back-flush fluid source to return blood to a patient in the event of a dialysate circuit failure during therapy. At step 1002, a fluid line to a recoil storage container (eg, recoil fluid source 901) may be unblocked or opened. This can be accomplished, for example, by opening a pinch valve of a fluid line, such as valve 911 of the saline line. At step 1004, the dialysate may be back-filtered through the dialyzer into a fluid line and into a backflush storage container. At step 1006, the dialysis treatment may be completed. Alternatively, the dialysate circuit may experience a fault condition. Finally, at step 1008, the patient may be backflushed using the back-filtered dialysate in the backflush storage container. In some embodiments, in the case of very long treatments (eg, longer than 24 hours), it may be necessary to periodically refresh the fluid to address concerns about microbial growth. In this embodiment, all fluid from the fluid source can be pumped out of the fluid source through the dialyzer to drain, and then the same process described above can be initiated to refill the fluid source.

When a feature or element is referred to herein as being "on" another feature or element, it can be directly on the other feature or element, or intervening features or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that when a feature or element is referred to as being "connected," "attached" or "coupled" to another feature or element, it can be directly connected, attached or coupled to the other feature or element, or there can be present An intermediate feature or element. In contrast, when a feature or element is referred to as being "directly connected," "directly attached" or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or illustrated with respect to one embodiment, the features and elements so described or illustrated may apply to other embodiments. Those skilled in the art will also recognize that references to a structure or a feature that is disposed "adjacent" to another feature may have portions that overlap or underlie the adjacent feature.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should be further understood that the terms "comprises" and/or "comprising" when used in this specification specify the presence of stated features, steps, operations, elements and/or parts, but do not exclude the presence or Add one or more other features, steps, operations, elements, parts and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items, and may be abbreviated as "/".

For ease of description, spatially relative terms such as "under", "below", "lower", "above" may be used herein (over)", "upper (upper)", etc., to describe the relationship between one element or feature and other elements or features as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of "above" and "beneath". The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly," "downwardly," "vertical," "horizontal," etc. are used herein for purposes of description unless specifically stated otherwise .

Although the terms "first" and "second" may be used herein to describe various features/elements (including steps), these features/elements should not be limited by these terms unless the context dictates otherwise. These terms can be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed below could be termed a second feature/element, and, similarly, a second feature/element discussed below could be termed a first feature/element without departing from the teachings of the present invention. /element.

In this specification and the appended claims, unless the context requires otherwise, the term "comprise" and variations thereof such as "comprises" and "comprising" mean elements that may be included in methods and articles of manufacture. Various components are commonly used in (for example, compositions and devices, including devices and methods). For example, the term "comprising" will be understood to imply the inclusion of any stated elements or steps, but not the exclusion of any other elements or steps.

As used herein in the specification and claims, including in the examples and unless expressly stated otherwise, all numbers may be read as preceded by the word "about" or "approximately", Even if the term doesn't appear explicitly. The phrases "about" or "approximately" may be used in describing magnitude and/or location to indicate that the described value and/or location is within a reasonably expected range of value and/or location. For example, a numerical value may have +/- 0.1% of a stated value (or range of values), +/- 1% of a stated value (or range of values), a stated value (or range of values) +/- 2% of a stated value (or range of values), +/- 5% of a stated value (or range of values), +/- 10% of a stated value (or range of values), etc. Any numerical value given herein should also be understood to include about or approximately that value, unless the context dictates otherwise. For example, if the value "10" is disclosed, then "about 10" is also disclosed. Any recitation of a numerical range herein is intended to include all subranges subsumed therein. It is also understood that when a value is disclosed, "less than or equal to" the value, "greater than or equal to the value" and possible ranges between values are also disclosed, as appropriately understood by those skilled in the art. For example, if the value "X" is disclosed, then "less than or equal to X" and "greater than or equal to X" are also disclosed (eg, where X is a numerical value). It should also be understood that throughout this application, data is provided in a variety of different formats and that this data represents endpoints and starting points and ranges for any combination of data points. For example, if a specific data point "10" and a specific data point "15" are disclosed, it should be understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 and between 10 and 15 are considered to be public. It is also understood that every unit between two specific units is also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13 and 14 are also disclosed.

While various illustrative embodiments have been described above, any of several changes may be made to the various embodiments without departing from the scope of the present invention as described in the claims. For example, the order of performing various described method steps may generally be varied in alternative embodiments, and in other alternative embodiments, one or more method steps may be skipped altogether. Optional features of the various apparatus and system embodiments may be included in some embodiments and not in others. Accordingly, the foregoing description is provided mainly for exemplary purposes and should not be construed as limiting the scope of the invention as set forth in the claims.

The examples and descriptions included herein show specific embodiments in which the subject matter may be practiced by way of illustration and not limitation. As mentioned, other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein, individually or collectively, by the term "invention" for convenience only, and it is not intended to limit the scope of this application if more than one are actually disclosed. Limitations are positively limited to any single invention or inventive concept. Therefore, although specific embodiments have been shown and described herein, any arrangement that is considered to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reading the above description.

Claims (24)

1. A method of improving the performance of a dialysis tubing, the dialysis tubing comprising an arterial line and further comprising a fluid delivery line connecting a fluid source to the dialysis tubing, the method comprising the steps of:

occlusion of the arterial line of the dialysis tubing;

opening or releasing a clamping mechanism engaged with the fluid delivery line;

regulating a pump speed of a blood pump engaged with the dialysis tubing to increase a fluid pressure within the dialysis tubing; and

fluid is delivered from the fluid source through the fluid delivery line into the dialysis tubing.

2. The method of claim 1, wherein regulating the pump speed of the blood pump comprises increasing a flow rate of the blood pump from a first flow rate to a second flow rate.

3. The method of claim 1, wherein regulating the pump speed of the blood pump comprises reducing a flow rate of the blood pump from a first flow rate to a second flow rate.

4. The method of claim 1, wherein regulating the pump speed of the blood pump comprises pulsing a flow rate of the blood pump.

5. The method of claim 1, wherein regulating the pump speed of the blood pump comprises reducing a flow rate of the blood pump from about 320ml/min to about 180ml/min.

6. The method of claim 1, further comprising automatically scheduling the occluding step, the opening step, and the modulating step to occur periodically during the dialysis treatment.

7. The method of claim 1, wherein a portion of the fluid delivery line remains occluded after opening or releasing the clamping mechanism due to the pre-extension clamping of the fluid delivery line.

8. The method of claim 1, wherein a portion of the fluid delivery line remains partially occluded after opening or releasing the clamping mechanism due to the front extension clamping of the fluid delivery line.

9. The method according to claim 1, further comprising the method steps of:

unblocking the arterial line;

closing or compressing the clamping mechanism in engagement with the fluid delivery line; and

dialysis treatment is initiated.

10. A dialysis system comprising:

a fluid source;

a dialysis tubing set comprising at least an arterial line, a blood pump portion and a fluid delivery line connecting the fluid source to the dialysis tubing set;

a blood pump configured to engage with the blood pump portion of the dialysis tubing set;

A first clamping mechanism configured to engage the arterial line;

a second clamping mechanism configured to engage the fluid delivery line; and

an electronic controller configured to control operation of the blood pump, the first clamping mechanism, and the second clamping mechanism, wherein during a priming sequence, the electronic controller is configured to:

closing or occluding the first clamping mechanism;

opening or unblocking the second clamping mechanism;

the pump speed of the blood pump is regulated to increase the fluid pressure within the dialysis tubing set and to deliver fluid from the fluid source through the fluid delivery line into the dialysis tubing.

11. The system of claim 10, wherein the electronic controller is configured to regulate the pump speed of the blood pump by increasing a flow rate of the blood pump from a first flow rate to a second flow rate.

12. The system of claim 10, wherein the electronic controller is configured to regulate the pump speed of the blood pump by reducing a flow rate of the blood pump from a first flow rate to a second flow rate.

13. The system of claim 10, wherein the electronic controller is configured to regulate the pump speed of the blood pump by pulsing a flow rate of the blood pump.

14. The system of claim 10, wherein the electronic controller is configured to regulate the pump speed of the blood pump, including reducing a flow rate of the blood pump from about 320ml/min to about 180ml/min.

15. The system of claim 10, wherein the controller is configured to automatically perform the closing step, the opening step, and the regulating step periodically during a dialysis treatment.

16. The system of claim 10, wherein a portion of the fluid delivery line remains occluded after opening or releasing the clamping mechanism due to the front extension clamping of the fluid delivery line.

17. The system of claim 10, wherein a portion of the fluid delivery line remains partially occluded after opening or releasing the clamping mechanism due to the front extension clamping of the fluid delivery line.

18. The system of claim 10, wherein the electronic controller is further configured to:

Unblocking the arterial line;

closing or compressing the clamping mechanism in engagement with the fluid delivery line; and

dialysis treatment is initiated.

19. A method of improving the performance of a dialyzer during dialysis treatment, comprising the steps of:

starting dialysis treatment;

detecting a pressure difference between a blood side of the dialyzer and a dialysate side of the dialyzer;

if the pressure differential exceeds a predetermined threshold, then:

occlusion of the arterial line of the dialysis tubing;

opening or releasing a clamping mechanism engaged with the fluid delivery line;

regulating a pump speed of a blood pump engaged with the dialysis tubing to increase a fluid pressure within the dialysis tubing; and

fluid is delivered from a fluid source through the fluid delivery line into the dialysis tubing.

20. The method of claim 19, wherein regulating the pump speed of the blood pump comprises increasing a flow rate of the blood pump from a first flow rate to a second flow rate.

21. The method of claim 19, wherein regulating the pump speed of the blood pump comprises reducing a flow rate of the blood pump from a first flow rate to a second flow rate.

22. The method of claim 19, wherein regulating the pump speed of the blood pump comprises pulsing a flow rate of the blood pump.

23. A method of returning blood to a patient after a dialysis treatment using a dialysis system comprising a fluid delivery line connecting a fluid receptacle to a dialysis tubing set, the method comprising the steps of:

opening or releasing a clamping mechanism engaged with the fluid delivery line;

back-filtering dialysate through a dialyzer of the dialysis system, into the dialysis tubing set, and into the fluid receptacle via the fluid delivery line;

performing a dialysis treatment with the dialysis system, including drawing blood into the dialysis tubing set; and

the blood is returned to the patient with the back-filtered dialysate in the fluid receptacle.

24. The method of claim 23, wherein back filtering dialysate through the dialyzer further comprises controlling a first dialysate pump located upstream of the dialyzer to have a faster pump speed than a second dialysate pump located downstream of the dialyzer.

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