Dialysis apparatus and control methods

Abstract

This invention provides a dialysis apparatus that reduces the burden on patients based on the circulatory dynamics of blood after supplemental fluid injection, and a method for controlling the rate of water removal. The dialysis apparatus 100 of this invention includes: a blood circuit 110; a blood purification unit 120; a dialysate circuit 130; a circulating blood volume measurement unit 140; a supplemental fluid injection unit for injecting supplemental fluid into the blood circuit 110; and a control unit 150 that controls the supplemental fluid injection unit to inject a predetermined amount of supplemental fluid into the blood circuit 110 intermittently at predetermined intervals. When water is removed from the blood by the blood purification unit 120, and the rate of decrease in the rate of change of the most recent supplemental fluid injection, as measured by the circulating blood volume measurement unit 140, exceeds a first threshold, the control unit 150 reduces the rate of water removal by the blood purification unit 120.

Description

Technical Field

[0001] This invention relates to dialysis apparatus and control methods using the dialysis apparatus. Background Technology

[0002] During dialysis treatment, a pump is used to draw blood from the patient's arterial side and deliver it to blood purification units such as dialyzers and hemodialysis filters, so that the blood, which has been freed of waste and excess water, is returned to the patient's venous side.

[0003] In a typical dialysis treatment, blood purification takes about 4 hours per session. As dialysis progresses, the blood is gradually purified, and excess water in the body is gradually removed. This blood purification gradually reduces the amount of circulating blood flowing through the patient's body, so it is not uncommon for patients to experience a drop in blood pressure in the latter half of dialysis treatment.

[0004] In cases of reduced circulating blood volume, normal biological responses involve the autonomic nervous system causing peripheral vasoconstriction, thus maintaining central circulating blood volume. Additionally, when blood is concentrated through dehydration, the osmotic pressure difference causes plasma components to move from the interstitium into the blood vessels, refilling the system and maintaining circulating blood volume. However, depending on the patient, these biological responses may not occur normally, and sometimes a drop in blood pressure makes it difficult to continue dialysis treatment.

[0005] In cases of such a drop in blood pressure, in order to quickly increase the circulating blood volume, treatments such as using saline or purified dialysate to replenish fluids are employed.

[0006] In addition, in recent years, in order to prevent the drop in blood pressure caused by the reduction in circulating blood volume associated with water removal, an "intermittent supplemental hemodiafiltration method" has been proposed in the treatment of hemodialysis (HD) and hemodiafiltration (HDF). For example, 150 mL to 200 mL of fluid is repeatedly administered every 30 minutes to add an equivalent amount of water to the original water removal volume for water removal (see Non-Patent Literature 1 and Non-Patent Literature 2).

[0007] Existing technical documents

[0008] Non-patent literature

[0009] Non-patent literature 1: "A Study of the New HDF Therapy and Its Clinical Efficacy" from the Journal of the Japanese Dialysis Medicine Society, Vol. 40, No. 9, pp. 769-774.

[0010] Non-Patent Literature 2: Journal of the Japanese Dialysis Medicine Society, Vol. 42, No. 9, pp. 695-703, "A Study and Clinical Evaluation of Intermittent Fluid Replacement Hemodialysis in Automated Mode Using Reverse Filtration Dialysis Fluid" Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] As mentioned above, planned fluid resuscitation during dialysis can suppress the drop in blood pressure. However, because the increased fluid volume from the resuscitation is added to the original dehydration rate, the dehydration rate increases compared to dialysis without resuscitation. The circulatory dynamics of blood during dialysis (circulating blood volume, plasma refill rate, etc.) vary from patient to patient. Therefore, if dehydration is performed at an increased rate, the rate of decrease in circulating blood volume may increase, potentially becoming a burden on the patient.

[0013] Therefore, the object of the present invention is to provide a dialysis device and a method for controlling the rate of water removal that can reduce the burden on the patient based on the circulatory dynamics of the blood after the injection of supplemental fluid.

[0014] Methods for solving problems

[0015] This invention relates to a dialysis apparatus, comprising: a blood circuit; a blood purification unit disposed in the blood circuit and capable of removing water from the blood; a dialysate circuit connected to the blood purification unit for introducing and removing dialysate; a measuring unit for measuring the rate of change of circulating blood volume; a replenishment fluid injection unit for injecting replenishment fluid into the blood circuit to restore the circulating blood volume reduced by water removal; and a control unit for controlling the replenishment fluid injection unit to intermittently inject a predetermined amount of replenishment fluid into the blood circuit at predetermined intervals. The control unit, when removing water from the blood through the blood purification unit, reduces the water removal rate of the blood purification unit when the rate of decrease after the most recent replenishment fluid injection, as measured by the measuring unit, exceeds a first threshold. It should be noted that the rate of change of circulating blood volume can also be determined by measuring hematocrit. Furthermore, the change in hematocrit (e.g., the rate of increase) can be used as an indicator to control the blood purification process in the same way as the circulating blood volume.

[0016] In addition, it is preferable to use the aforementioned blood purification unit and the aforementioned dialysate circuit as the aforementioned replenishment fluid injection unit, and to use the dialysate filtered in reverse by the aforementioned blood purification unit as the aforementioned replenishment fluid.

[0017] Furthermore, the present invention relates to a method for controlling the dehydration rate using a dialysis apparatus having the following structure: a blood circuit; a blood purification unit disposed in the blood circuit and capable of removing water from the blood; a dialysate circuit connected to the blood purification unit for introducing and exporting dialysate to the blood purification unit; a measuring unit that measures the rate of change of circulating blood volume; a replenishment fluid injection unit that injects replenishment fluid into the blood circuit to restore the circulating blood volume reduced due to dehydration; and a control unit that controls the replenishment fluid injection unit to intermittently inject a predetermined amount of replenishment fluid into the blood circuit at predetermined intervals. In this control method, the rate of change measured by the measuring unit is used to calculate the rate of decrease of the rate of change after the most recent replenishment fluid injection, and if the calculated rate of decrease of the rate of change exceeds a first threshold, the dehydration rate of the blood purification unit is reduced.

[0018] In addition, the aforementioned first threshold of 2% / minute is preferred.

[0019] Furthermore, if the rate of decrease of the aforementioned change rate after the injection of the most recent replenishing fluid, as measured by the aforementioned measuring unit, is less than the second threshold after the dehydration rate of the aforementioned blood purification unit is reduced, it is preferable to return the dehydration rate of the aforementioned blood purification unit to the rate before the reduction.

[0020] In addition, the aforementioned second threshold of 1% / minute is preferred.

[0021] In addition, when reducing the water removal rate of the aforementioned blood purification unit, it is preferable to control the amount of fluid injected in the next replenishment and / or extend the injection interval.

[0022] The effects of the invention

[0023] According to the present invention, the rate of dehydration can be controlled by adjusting the rate of decrease in the rate of change of circulating blood volume, thereby reducing the burden on the patient based on the dynamics of blood circulation. Attached Figure Description

[0024] Figure 1 This is a diagram showing the general structure of a dialysis device.

[0025] Figure 2 This is a diagram showing the dialysis process performed using a dialysis apparatus.

[0026] Figure 3 This diagram illustrates the fluid replenishment process performed using a dialysis unit.

[0027] Figure 4 This is a graph showing the rate of change in circulating blood volume during fluid resuscitation in dialysis.

[0028] Figure 5 This is a flowchart illustrating the dialysis treatment process of the present invention.

[0029] Figure 6 This is a flowchart illustrating the method for controlling the dewatering speed of the present invention. Detailed Implementation

[0030] Hereinafter, preferred embodiments of the dialysis apparatus and control method of the present invention will be described with reference to the accompanying drawings.

[0031] The control method of the present invention can be applied to situations where intermittent fluid replacement is performed in dialysis treatments such as hemodialysis (HD) and hemodiafiltration (HDF). As an application example of the present invention, the case of intermittent supplemental hemodiafiltration, in which intermittent fluid replacement is performed using reverse-filtered dialysate, will be described.

[0032] <First Embodiment>

[0033] like Figure 1 As shown, the dialysis apparatus 100 includes a blood circuit 110 for circulating blood, a blood purification unit 120, a dialysate circuit 130, a circulating blood volume measuring unit 140 disposed in the blood circuit 110, and a control unit 150.

[0034] The blood circuit 110 has an arterial side line 111, a venous side line 112, a drug line 113, and a pre-flushing fluid discharge line 114. The arterial side line 111, the venous side line 112, the drug line 113, and the pre-flushing fluid discharge line 114 are all mainly composed of flexible soft tubes that allow liquid to flow.

[0035] One end of the arterial side conduit 111 is connected to the blood inlet 122a of the blood purification unit 120, which will be described later. The arterial side conduit 111 is equipped with an arterial side connection 111a, an arterial side bubble detector 111b, a blood pump 111c, and a circulating blood volume measurement unit 140.

[0036] An arterial side connector 111a is disposed at the other end of the arterial side conduit 111. A needle for puncturing a patient's blood vessel is connected to the arterial side connector 111a.

[0037] The arterial side bubble detector 111b detects the presence or absence of bubbles in the tube.

[0038] The blood pump 111c is positioned downstream of the arterial bubble detector 111b in the arterial side conduit 111. The blood pump 111c delivers blood, pre-fluid, and other liquids from inside the arterial side conduit 111 by rolling the tube that forms the arterial side conduit 111 with rollers.

[0039] One end of the venous side tubing 112 is connected to the blood outlet 122b of the blood purification unit 120, which will be described later. The venous side tubing 112 is provided with a venous side connector 112a, a venous side air bubble detector 112b, a drip chamber 112c, and a venous side clamp 112d.

[0040] A venous-side connector 112a is disposed at the other end of the venous-side conduit 112. A needle for puncturing a patient's blood vessel is connected to the venous-side connector 112a.

[0041] The venous side bubble detector 112b detects the presence or absence of bubbles in the tube.

[0042] The dripper 112c is positioned upstream of the venous-side air bubble detector 112b. The dripper 112c stores a certain amount of blood to remove air bubbles, coagulated thrombi / clots, etc., that have entered the venous-side tubing 112, and to measure venous pressure.

[0043] The vein-side clamp 112d is positioned downstream of the vein-side bubble detector 112b. The vein-side clamp 112d is controlled to open and close the flow path of the vein-side conduit 112 based on the bubble detection results from the vein-side bubble detector 112b.

[0044] The medication line 113 supplies the medications necessary for hemodialysis to the arterial side line 111. One end of the medication line 113 is connected to the medication pump 113a, which delivers the medication, and the other end is connected to the arterial side line 111. Additionally, the medication line 113 is equipped with a clamping unit (not shown), which keeps the flow path closed except during medication injection. In this embodiment, the other end of the medication line 113 is connected upstream of the circulating blood volume measuring unit 140 in the arterial side line 122.

[0045] The pre-flushing fluid discharge line 114 is connected to the dripper 112c. A pre-flushing fluid discharge line clamp 114a is provided in the pre-flushing fluid discharge line 114. The pre-flushing fluid discharge line 114 is used to discharge the pre-flushing fluid in the pre-flushing process described later.

[0046] The blood purification unit 120 includes a cylindrical container body 121 and a dialysis membrane (not shown) housed inside the container body 121. The interior of the container body 121 is divided into a blood-side flow path and a dialysate-side flow path (both not shown) by the dialysis membrane. The container body 121 has a blood inlet 122a and a blood outlet 122b connected to the blood circuit 110, and a dialysate inlet 123a and a dialysate outlet 123b connected to the dialysate circuit 130.

[0047] Through the blood circuit 110 and blood purification unit 120 described above, blood drawn from the artery of the patient (dialysis patient) is circulated through the arterial side tubing 111 and introduced into the blood side flow path of the blood purification unit 120 by the blood pump 111c. The blood introduced into the blood purification unit 120 is purified by dialysate flowing through the dialysate circuit 130 described later via the dialysate membrane. The purified blood in the blood purification unit 120 flows through the venous side tubing 112 and returns to the patient's vein.

[0048] In this embodiment, the dialysate circuit 130 is configured as a dialysate circuit 130 with a so-called closed-loop capacity control method. The dialysate circuit 130 includes a dialysate supply line 131a, a dialysate discharge line 131b, a dialysate inlet line 132a, a dialysate outlet line 132b, and a dialysate delivery section 133.

[0049] The dialysate delivery unit 133 includes a dialysate chamber 1331, a bypass line 1332, and a dewatering / reverse filtration pump 1333.

[0050] The dialysate chamber 1331 is made of a rigid container capable of holding a certain volume (e.g., 300ml to 500ml) of dialysate. The interior of the container is divided into a delivery receiving section 1331a and a discharge receiving section 1331b by a soft dialysis membrane.

[0051] The bypass line 1332 connects the dialysate outlet line 132b and the dialysate drainage line 131b.

[0052] A dewatering / reverse filtration pump 1333 is disposed in a bypass line 1332. The dewatering / reverse filtration pump 1333 is a pump that is driven to deliver liquid in a direction that allows the dialysate inside the bypass line 1332 to flow to the dialysate discharge line 131b (dewatering direction) and to flow to the dialysate outlet line 132b (reverse filtration direction).

[0053] The base end of the dialysate supply line 131a is connected to the dialysate supply device (not shown), and the front end is connected to the dialysate chamber 1331. The dialysate supply line 131a supplies dialysate to the liquid delivery and receiving section 1331a of the dialysate chamber 1331.

[0054] The dialysate inlet line 132a connects the dialysate chamber 1331 and the dialysate inlet 123a of the blood purification unit 120, and introduces the dialysate contained in the liquid delivery receiving part 1331a of the dialysate chamber 1331 into the dialysate side flow path of the blood purification unit 120.

[0055] The dialysate outlet 132b connects the dialysate outlet 123b of the blood purification unit 120 to the dialysate chamber 1331, and discharges the dialysate discharged from the blood purification unit 120 to the drain receiving part 1331b of the dialysate chamber 1331.

[0056] The base end of the dialysate drain line 131b is connected to the dialysate chamber 1331, and the dialysate contained in the drain receiving section 1331b is drained.

[0057] Based on the dialysate circuit 130 described above, by using a soft diaphragm (separation membrane) to divide the interior of the rigid container constituting the dialysate chamber 1331, the amount of dialysate discharged from the dialysate chamber 1331 (the amount of dialysate supplied to the liquid delivery container 1331a) can be equal to the amount of liquid discharged back to the dialysate chamber 1331 (the amount of liquid discharged to the liquid discharge container 1331b).

[0058] Therefore, when the dewatering / reverse filtration pump 1333 is stopped, the flow rate of the dialysate introduced into the blood purification unit 120 can be equal to the amount of dialysate (drainage) discharged from the blood purification unit 120.

[0059] Furthermore, when the dewatering / reverse filtration pump 1333 is driven to deliver fluid in the reverse filtration direction, a portion of the drained fluid discharged from the dialysate chamber 1331 is recycled back to the dialysate chamber 1331 via the bypass line 1332 and the dialysate outlet line 132b. Therefore, the amount of dialysate discharged from the blood purification unit 120 is obtained by subtracting the amount of dialysate flowing through the bypass line 1332 from the amount recycled to the dialysate chamber 1331 (i.e., the amount of dialysate flowing through the dialysate inlet line 132a). Thus, the amount of dialysate discharged from the blood purification unit 120 is only slightly less than the flow rate of dialysate flowing through the dialysate inlet line 132a by an amount equivalent to the amount of dialysate (drained fluid) that is subsequently collected back to the dialysate chamber 1331 via the bypass line 1332. That is, when the dewatering / reverse filtration pump 1333 is driven to deliver liquid in the reverse filtration direction, a predetermined amount of dialysate (reverse filtration) is injected into the blood circuit 110 in the blood purification unit 120 into the blood circuit 110 (refer to...). Figure 3 ).

[0060] In this embodiment, the blood purification unit 120 and the dialysate circuit 130 (water removal / reverse filtration pump 1333) are used as a replenishment fluid injection unit, using reverse-filtered dialysate as the replenishment fluid. In other words, regarding the dialysate as the replenishment fluid, by driving the water removal / reverse filtration pump 1333 in the reverse filtration direction, it can be injected from the dialysate circuit 130 into the blood circuit 110 via the blood purification unit 120. It should be noted that a replenishment fluid line can also be connected to the blood circuit 110 as a replenishment fluid injection unit, using physiological saline or the like as the replenishment fluid. Alternatively, a replenishment fluid line connected from the dialysate inlet line 132a to the arterial side line 111 or the venous side line 112, equipped with a replenishment fluid pump, can also be used as a replenishment fluid injection unit, using dialysate as the replenishment fluid.

[0061] On the other hand, when the dehydration / reverse filtration pump 1333 is driven in a manner that delivers fluid in the direction of dehydration, the amount of dialysate flowing in the dialysate outlet line 132b is the amount of dialysate recovered to the dialysate chamber 1331 (i.e., the amount of dialysate flowing in the dialysate inlet line 132a) plus the amount of dialysate flowing in the bypass line 1332. Therefore, the amount of dialysate flowing in the dialysate outlet line 132b is only slightly more than the amount of dialysate flowing in the dialysate inlet line 132a by an amount equivalent to the amount of dialysate (discharge) discharged through the bypass line 1332 to the dialysate discharge line 131b. That is, when the dehydration / reverse filtration pump 1333 is driven in a manner that delivers fluid in the direction of dehydration, a predetermined amount of water is removed from the blood in the blood purification unit 120 (see reference). Figure 2 ).

[0062] The circulating blood volume measurement unit 140 is a sensor that measures the hematocrit value of blood flowing within the blood circuit 110. For example, the hematocrit value can be measured based on the light transmittance of blood obtained by irradiating it with near-infrared light. The rate of change in the circulating blood volume in a patient can be calculated based on the hematocrit value measured over time using the circulating blood volume measurement unit 140. Figure 1 As shown, in order to make the circulating blood volume measuring unit 140 less susceptible to the effects of water removal and fluid replenishment by the blood purification unit 120, the blood pump 111c in the arterial side pipeline 111 is positioned downstream of the blood pump 111c and upstream of the blood purification unit 120.

[0063] The control unit 150, comprised of an information processing device (computer), controls the operation of the dialysis apparatus 100 by executing a control program. Furthermore, the control unit 150 calculates the rate of change in circulating blood volume based on the hematocrit value measured by the circulating blood volume measurement unit 140. Additionally, the control unit 150 calculates the rate of decrease in the rate of change of circulating blood volume after the completion of the supplemental fluid infusion.

[0064] Specifically, the control unit 150 controls the operation of various pumps, clamps, etc., configured in the blood circuit 110 and the dialysate circuit 130, thereby executing various processes performed through the dialysis apparatus 100, such as pre-flushing, blood removal, dialysis, fluid replenishment, and blood return.

[0065] Reference Figure 2 and Figure 3 The various processes are explained briefly.

[0066] In the pre-rinsing process, reverse filtration dialysis fluid is used as the pre-rinsing fluid to clean the blood circuit 110 and the blood purification unit 120 for purification.

[0067] In the blood removal process, the patient's blood is aspirated to fill the arterial side tubing 111 and the venous side tubing 112. Following the blood removal process is a dialysis process to purify the blood and remove excess water (see [reference]). Figure 2 During the dialysis process, excess water from the patient is removed, and additional water is removed from the fluid replenishment volume.

[0068] A fluid replacement procedure is performed intermittently during the dialysis process (see reference). Figure 3 After the dialysis process is completed, a blood return procedure is performed to return the blood to the patient.

[0069] The following describes in detail the dialysis process and fluid replacement process, which involve changes in the circulating blood volume, among the various processes performed through the dialysis apparatus 100.

[0070] Reference Figure 2 The dialysis procedure is explained.

[0071] During the dialysis process, the patient's blood introduced from the arterial side connection 111a is purified in the blood purification unit 120 through the arterial side tubing 111, and then returned to the patient from the venous side connection 112a through the venous side tubing 112.

[0072] like Figure 2 As shown, during the dialysis process, the arterial side connection 111a and the venous side connection 112a are respectively connected to the needles in the punctured patient's blood vessels, the pre-fluid discharge tubing clamp 114a is in the closed state, and the venous side clamp 112d is in the open state.

[0073] A dialysate supply device (not shown) supplies and discharges dialysate to the dialysate chamber 1331 at an average rate of 500 ml / min, causing the dehydration / reverse filtration pump 1333 to operate in a manner that delivers dialysate in the direction of dehydration. As an example, if the delivery rate of the dehydration / reverse filtration pump 1333 is set to 10 ml / min, then dehydration will occur at a rate of 10 ml / min in the blood purification unit 120.

[0074] The blood pump 111c gradually increases the flow rate from 40-50 ml / min at the start of the dialysis process to, for example, about 200 ml / min, and delivers blood from the arterial side connection 111a to the blood purification unit 120.

[0075] Within the blood purification unit 120, blood flows in through the blood inlet 122a at a flow rate of 200 ml / min, is dehydrated at a flow rate of 10 ml / min, and is discharged through the blood outlet 122b at a flow rate of 190 ml / min. Additionally, dialysis fluid is discharged through the dialysate outlet 123b.

[0076] In this way, water is gradually removed from the blood during the dialysis process, and the amount of circulating blood gradually decreases.

[0077] Next, refer to Figure 3 The liquid replenishment process is explained.

[0078] The fluid replenishment process is the process of injecting reverse dialysis filtrate into the blood circuit 110. In this embodiment, in order to prevent the decrease in blood pressure caused by the reduction in circulating blood volume due to water removal, it is performed intermittently at a predetermined interval.

[0079] like Figure 3 As shown, in the fluid replenishment process, similar to the dialysis process, the arterial side connection 111a and the venous side connection 112a are respectively connected to the needles of the punctured patient's blood vessels, the pre-fluid discharge tubing clamp 114a is in the closed state, and the venous side clamp 112d is in the open state.

[0080] A dialysate supply device (not shown) supplies and discharges dialysate to the dialysate chamber 1331 at an average rate of 500 ml / min, causing the dehydration / reverse filtration pump 1333 to operate in the reverse filtration direction. For example, in the case of replenishing 200 ml of fluid, as an example, the delivery rate of the dehydration / reverse filtration pump 1333 is set to 150 ml / min, thereby replenishing fluid at a rate of 150 ml / min in the blood purification unit 120 over approximately 80 seconds.

[0081] The blood pump 111c gradually reduces the flow rate from 200 ml / min in the dialysis process to about 50 ml / min, and delivers blood from the arterial side connection 111a to the blood purification unit 120.

[0082] Within the blood purification unit 120, blood flows in through the blood inlet 122a at a flow rate of 50 ml / min, while reverse-filtered dialysate is replenished at a flow rate of 150 ml / min. The diluted blood is then discharged through the blood outlet 122b at a flow rate of 200 ml / min. This allows for the rapid replenishment of dialysate into the blood within approximately 80 seconds during the replenishment process.

[0083] Next, refer to Figure 4 and Figure 5 The specific method for controlling the water removal rate in this embodiment will be explained.

[0084] First, let me briefly explain the effects of intermittent fluid replacement.

[0085] During dialysis, as dehydration proceeds, water (plasma) is gradually removed from the blood, and the circulating blood volume gradually decreases. When the circulating blood volume decreases and the protein concentration in the blood increases, due to the osmotic pressure difference between the intravascular and extravascular spaces (interstitium), water (plasma) gradually moves from the interstitium into the blood vessels (plasma refill), restoring the circulating blood volume and maintaining blood pressure. However, when the rate of plasma refill cannot keep up with the rate of dehydration, and the circulating blood volume decreases while blood pressure continues to drop, a biological response occurs where the autonomic nervous system causes peripheral vasoconstriction in an attempt to maintain blood pressure. This results in a decrease in the rate of plasma refill caused by peripheral vasoconstriction, making it much lower than the rate of dehydration. The rate of decrease in circulating blood volume increases, leading to a sharp drop in blood pressure.

[0086] To prevent such a sharp drop in blood pressure, intermittent fluid resuscitation is administered. Dialysis is performed while fluid resuscitation is administered to restore blood circulation, thereby preventing a drop in blood pressure and also improving peripheral circulation and maintaining the rate of plasma refilling. As a result, compared to the case without fluid resuscitation, even at the same rate of water removal (excluding fluid recovery), the rate of reduction in circulating blood volume at the end of dialysis is reduced. It should be noted that the increase in circulating blood volume resulting from fluid resuscitation is achieved by increasing the water removal rate of the blood purification unit 120 from the start to the end of dialysis. Therefore, the total amount of water removed is the sum of the patient's remaining water (water removed by body weight) and the amount of fluid recovered.

[0087] The present invention achieves the above-mentioned effects by implementing fluid replacement, and by appropriately controlling the rate of water removal after fluid replacement injection, a dialysis procedure that reduces the burden on patients can be implemented.

[0088] Next, the shift in the rate of change of circulating blood volume when fluid resuscitation is performed under normal conditions will be explained.

[0089] Figure 4A graph illustrating the rate of change in circulating blood volume during fluid resuscitation under the usual conditions of an infusion volume of 200 ml and an infusion interval of 30 minutes. (See figure.) Figure 4 As shown, the rate of change in circulating blood volume increases when fluid replacement is administered every 30 minutes, and then decreases after the fluid replacement is stopped and dehydration is restarted. Figure 4 The slope of the white arrows shown represents the rate of decrease in the rate of change of circulating blood volume. A steeper slope indicates a faster rate of decrease, while a shallower slope indicates a slower rate of decrease. It should be noted that in this embodiment, the average rate of decrease is used as the rate of decrease. Here, the average rate of decrease is calculated from the moment the rate of change transitions from increase to decrease after the most recent administration of replacement fluid, taking that moment as the starting point, and is calculated from the amount of decrease in the rate of change at a given time and the elapsed time.

[0090] The inventors of this application conducted research on the rate of decrease of a suitable rate of change in circulating blood volume and concluded that, in order to reduce the burden on patients, it is desirable that the average rate of decrease in the rate of change does not exceed 2% / minute as a first threshold. Therefore, the dehydration rate is reduced in such a way that the average rate of decrease in the rate of change is below the first threshold. The dehydration rate can be, for example, reduced by the amount added for the recovery of replenishment fluid, or reduced by a predetermined percentage (e.g., 50%). Furthermore, when the average rate of decrease in the rate of change becomes smaller and falls below a second threshold that is smaller than the first threshold by reducing the dehydration rate, the plasma refill rate reaches the dehydration rate. Therefore, in order to increase the amount of water recovered from the increased replenishment fluid, it is desirable that the dehydration rate return to its original rate. Here, the second threshold is preferably 1% / minute.

[0091] Therefore, a method for controlling the dehydration rate of the blood purification unit 120 is specifically described such that the rate of decrease in the circulating blood volume after the injection of the supplemental fluid does not exceed a first threshold (2% / min) and is kept below a second threshold.

[0092] (Methods for controlling the water removal rate)

[0093] In this embodiment, as an example, refer to Figure 5 and Figure 6 This explanation addresses the case where the interval between fluid infusions is fixed at 30 minutes, and a total of 7 fluid infusions are administered over a 4-hour treatment period.

[0094] The control unit 150 measures the hematocrit value via the circulating blood volume measurement unit 140, and calculates the rate of change in circulating blood volume over time based on the measured hematocrit value. Additionally, after the supplemental fluid injection is completed, the average rate of decrease in the rate of change is calculated.

[0095] Reference Figure 5 The procedure for dialysis treatment is explained.

[0096] After dialysis begins, the dialysis apparatus 100 removes water at a predetermined rate (S100). After a predetermined time (S110), fluid is replenished at a predetermined volume (S120). Here, the predetermined rate of water removal in S100 refers to the rate of water removal at the start of dialysis treatment, which is based on the amount of water (water removal volume) that should be removed from the patient through dialysis treatment.

[0097] After fluid resuscitation, the rate of water removal is controlled based on the rate of decrease in the rate of change of circulating blood volume until a predetermined time has elapsed (S130).

[0098] Next, it is determined whether the prescribed dialysis time has elapsed (S140). This process is repeated until the prescribed dialysis time has elapsed, and fluid replacement is administered at a prescribed volume (S120) to control the rate of fluid removal. After the prescribed time has elapsed (S140), the dialysis treatment is terminated. Here, the prescribed dialysis time in S140 also refers to the dialysis time at the start of the dialysis treatment.

[0099] It should be noted that, in this embodiment, as an example, the end of dialysis treatment is determined by the elapsed time of the predetermined dialysis treatment. However, if the predetermined water removal is not completed within the predetermined water removal time at the start of dialysis treatment, the dialysis time may be extended until the predetermined water removal is completed.

[0100] Reference Figure 6 The method for setting the water removal speed is explained.

[0101] After injecting replenishing solution by performing the recent replenishment, in order to recover water equivalent to the amount of replenishing solution injected, the water removal rate is increased compared to the water removal rate in S100 (S131).

[0102] Next, it is determined whether the average rate of decrease of the rate of change exceeds the first threshold (S132). If the average rate of decrease exceeds the first threshold, the water removal rate is reduced (S133). If it does not exceed the first threshold, the water removal rate is maintained (S134).

[0103] If the dewatering rate is decreased (S133), determine whether the average rate of decrease in the rate of change is below a second threshold (S135). If the average rate of decrease is determined to be above the second threshold, maintain the decreasing dewatering rate (S137) until the time specified in S138 has elapsed, and repeat the determination in S135. If the time specified in S138 has elapsed, end the control of the dewatering rate. The time specified in S138 refers to the time until the next fluid replenishment is performed; if the specified dialysis time has elapsed, the time specified in S138 has also elapsed. If the average rate of decrease is determined to be below the second threshold, return the dewatering rate to its original rate, i.e., the rate before the decrease (the dewatering rate in S131) ​​(S136).

[0104] While maintaining the dehydration rate (S134), the process returns to S132 for determination before the specified time has elapsed (S139). It is determined whether the average rate of decrease in the rate of change is lower than a second threshold, which is smaller than the first threshold (S135). If the average rate of decrease is determined to be above the second threshold, the dehydration rate is maintained at a decreasing state (S137) until the specified time in S139 has elapsed, and the determination in S135 is repeated. The specified time in S139 is the same as in S138, which is the time until the next fluid replenishment is performed; if the specified dialysis time has elapsed, then the specified time in S139 has also elapsed.

[0105] As explained above, when dehydration is performed at an increased rate to recover fluids, and the average rate of decrease in the rate of change of circulating blood volume exceeds a first threshold, the average rate of decrease in the rate of change can be reduced by decreasing the dehydration rate, thereby reducing the burden on the patient.

[0106] Furthermore, if the next fluid resuscitation / dialysis treatment ends while the dehydration rate is reduced, the recovery of the water injected as resuscitation fluid becomes difficult. Therefore, if the average rate of decrease in the rate of change caused by reducing the dehydration rate is below a second threshold, the amount of unrecovered water in the increased resuscitation fluid volume can be reduced by restoring the dehydration rate to its pre-decreasing rate. Additionally, if unrecovered water exists in the increased resuscitation fluid volume at the scheduled start time of the next resuscitation, the next resuscitation can be performed as planned while the unrecovered water remains, or the unrecovered amount can be subtracted from the next resuscitation volume before resuscitation. Alternatively, the infusion interval can be extended by lengthening the time until the next resuscitation is performed before dehydrating the unrecovered water. These two methods can also be used to adjust the amount of unrecovered water.

[0107] The dialysis apparatus 100 and the first control method according to the first embodiment described above can achieve the following effects.

[0108] (1) The dialysis apparatus 100 includes the following structure: a blood circuit 110; a blood purification unit 120; a dialysate circuit 130; a circulating blood volume measurement unit 140; a dialysate injection unit for injecting supplemental fluid into the blood circuit 110; and a control unit 150 for controlling the dialysate injection unit to inject a predetermined amount of supplemental fluid into the blood circuit 110 intermittently at predetermined intervals. The control unit 150, when removing water from the blood through the blood purification unit 120, reduces the rate of decrease in the rate of change of the most recent supplemental fluid injection (as measured by the circulating blood volume measurement unit 140) after the injection ends, if this rate exceeds a first threshold. This allows the rate of decrease in the circulating blood volume to be below the first threshold, thereby reducing the burden on the patient.

[0109] (2) After reducing the dehydration rate of the blood purification unit 120, if the rate of decrease in the rate of change of the most recent replenishment fluid injection, as measured by the circulating blood volume measurement unit 140, is lower than the second threshold, the control unit 150 returns the dehydration rate of the blood purification unit 120 to the rate before the reduction. As a result, less water is not recovered in the increase in replenishment fluid volume that accompanies the decrease in dehydration rate.

[0110] (3) When the dehydration rate of the blood purification unit 120 is reduced, the control unit 150 controls the amount of replenishing fluid injected in the next cycle to be reduced, and / or controls the injection interval to be extended. As a result, the amount of unrecovered water in the increase in replenishing fluid as the dehydration rate decreases can be further reduced.

[0111] (4) The control method for using the dialysis device 100 is configured as follows: the rate of change of circulating blood volume due to the recent infusion of supplemental fluid is calculated using the rate of change measured by the circulating blood volume measurement unit 140; if the calculated rate of decrease exceeds a first threshold, the dehydration rate of the blood purification unit 120 is reduced. This ensures that the rate of decrease of circulating blood volume is below the first threshold, thereby reducing the burden on the patient.

[0112] The preferred embodiments of the dialysis apparatus and control method of the present invention have been described above, but the present invention is not limited to the above embodiments and can be appropriately modified.

[0113] For example, in the above embodiment, the case of using the reverse-filtered dialysate as the replenishing fluid was described, but it is not limited to this. For example, physiological saline may also be used as the replenishing fluid, or the dialysate may be replenished directly from the dialysate tubing connected to the blood circuit without going through the blood purification unit. In addition, with such a structure, the dehydration process in the blood purification unit can be continued without stopping. That is, the replenishing fluid can be injected while maintaining the dehydration rate.

[0114] Furthermore, in the above embodiments, an example was shown of controlling the dehydration rate by increasing the dehydration rate after fluid resuscitation to recover the water added by the resuscitation fluid, but this is not a limitation. For example, the recovery of the water added by the resuscitation fluid may also begin before the fluid resuscitation is performed. Since the dehydration rate is increased, similar to the above embodiments, if the rate of decrease in the rate of change of circulating blood volume exceeds a first threshold, it is acceptable to control the dehydration rate by decreasing it.

[0115] Furthermore, in the above embodiment, the average rate of decrease is used as the rate of decrease of the rate of change of circulating blood volume, but it is not limited to this. For example, the instantaneous rate of decrease at a certain moment after the completion of the supplemental fluid injection can also be used as the rate of decrease of the rate of change. In this case, feedback control can be performed by increasing or decreasing the dehydration rate in such a way that the instantaneous rate of decrease of the rate of change is below a first threshold. In addition, regarding the upper limit of the dehydration rate, by setting it to the original dehydration rate (the dehydration rate increased to recover the increased amount of supplemental fluid), the dehydration rate is controlled to be close to the original dehydration rate within the range where the instantaneous rate of decrease does not exceed the first threshold, thereby reducing the amount of unrecovered water in the increased amount of supplemental fluid.

[0116] Explanation of reference numerals in the attached figures

[0117] 100 dialysis devices

[0118] 110 Blood Circuit

[0119] 111 Arterial side access

[0120] 111c Blood Pump

[0121] 112. Venous sideline catheter

[0122] 120 Blood Purification Unit

[0123] 130 Dialysis fluid circuit

[0124] 140 Circulating Blood Volume Measurement Unit (Measurement Unit)

[0125] 150 Control Department

Claims

1. A dialysis apparatus, comprising: Blood circulation; A blood purification unit, disposed in the blood circuit, is capable of removing water from the blood; A dialysate circuit is connected to the blood purification unit to introduce and export dialysate to the blood purification unit. A measuring unit, wherein the measuring unit measures the rate of change in circulating blood volume; A fluid replenishment unit that injects fluid into the blood circuit to restore the circulating blood volume reduced by dehydration; and The control unit controls the replenishment fluid injection unit to intermittently inject a predetermined amount of replenishment fluid into the blood circuit at predetermined intervals. in, When the blood purification unit removes water from the blood, and the rate of decrease in the rate of change after the most recent replenishment fluid injection, as measured by the measuring unit, exceeds a first threshold, the control unit reduces the water removal rate of the blood purification unit.

2. The dialysis apparatus as claimed in claim 1, wherein, The control unit controls the blood purification unit to return to the rate of water removal before reduction if the rate of decrease of the change rate after the injection of the most recent supplemental fluid, as measured by the measuring unit, is lower than a second threshold smaller than the first threshold.

3. The dialysis apparatus as described in claim 1 or 2, wherein, When the dehydration rate of the blood purification unit is reduced, the control unit controls the reduction of the injection volume of the next replenishing fluid and / or the extension of the injection interval.

4. The dialysis apparatus as described in claim 1 or 2, wherein, The blood purification unit and the dialysate circuit are used as the replenishment fluid injection unit, and the dialysate filtered in reverse by the blood purification unit is used as the replenishment fluid.

5. The dialysis apparatus as claimed in claim 1, wherein, The first threshold is 2% / minute.

6. The dialysis apparatus as claimed in claim 2, wherein, The second threshold is 1% / minute.

7. A dialysis apparatus, the dialysis apparatus comprising: Blood circulation; A blood purification unit, disposed in the blood circuit, is capable of removing water from the blood; A dialysate circuit is connected to the blood purification unit to introduce and export dialysate to the blood purification unit. A measuring unit that measures the hematocrit value of blood flowing through the blood circuit; A fluid replenishment unit that injects fluid into the blood circuit to restore the circulating blood volume lost due to dehydration; and The control unit controls the replenishment fluid injection unit to intermittently inject a predetermined amount of replenishment fluid into the blood circuit at predetermined intervals. Specifically, when the blood purification unit removes water from the blood, and the rate of increase in hematocrit value after the most recent replenishment fluid injection, as measured by the measuring unit, exceeds a predetermined threshold, the control unit reduces the water removal rate of the blood purification unit.

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