Fiber Optic Clot Detector with Ultrasonic Clot Neutralizer

Abstract

A method and system for detecting and neutralizing blood clots during dialysis (e.g., hemodialysis) is provided. A fiber optic sensor is provided in a hemodialysis machine to detect vibrations of blood cells, and the hemodialysis machine can be configured to prevent blood clotting by sounding an alarm, agitating blood cells, injecting saline, increasing temperature, and / or infusing heparin.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 676,570, filed on May 25, 2018, and U.S. Patent Application No. 16 / 405,558, filed on May 7, 2019, both of which are incorporated herein by reference in their entirety. Background Art

[0003] Patients with renal failure or partial renal failure are often treated with hemodialysis in a hemodialysis treatment center or clinic. When healthy, the kidneys maintain the body's internal balance of water and minerals (e.g., sodium, potassium, chloride, calcium, phosphorus, magnesium, and sulfate). The kidneys also produce the hormone erythropoietin as well as other hormones as part of the endocrine system. Hemodialysis is an imperfect treatment to replace kidney function, in part because it does not correct the kidney's endocrine function.

[0004] In hemodialysis, blood is extracted from the patient through a blood sampling needle (or catheter), which extracts blood from an artery located at a specific acceptable access location (arm, thigh, subclavian, etc.). The extracted blood is pumped through an extracorporeal tube via a peristaltic pump and then passes through a special filter called a "dialyser". The dialyzer is intended to remove undesirable toxins such as blood urea, nitrogen, potassium, and excess water from the blood. When blood passes through the dialyzer, it travels in a straw-like tube that serves as a semipermeable membrane channel for uncleaned blood. Fresh dialysis fluid (which is a solution of chemicals and water) flows through the dialyzer in the opposite direction to the blood flow. When the dialysate flows through the dialyzer, it surrounds the straw-like membrane in the dialyzer. These membranes have small holes that are large enough to pass liquid and liquid-based impurities, but not large enough to pass red blood cells. Fresh dialysate collects excess impurities through the straw-shaped tube by diffusion, and also collects excess water due to the pressure drop across the membrane by the ultrafiltration process. During this process, red blood cells are retained in the straw-shaped tube and recirculated back into the body. Used dialysate is discharged from the dialyzer with excess fluid and toxins via the output tube, thereby cleaning the blood and red blood cells flowing through the dialyzer. The dialyzed blood then flows out of the dialyzer via a tube and a needle (or catheter) and returns to the patient's body. Sometimes, a heparin drip device or pump is provided along the extracorporeal blood flow loop to prevent red blood cells from clotting during the hemodialysis process. During a typical treatment period of several hours, several liters of excess fluid can be removed. In the United States, chronic patients usually receive hemodialysis treatment three times a week in a dialysis center, either on a Monday-Wednesday-Friday schedule or on a Tuesday-Thursday-Saturday schedule. These intensive treatments are usually completed within 3 to 4 hours, and the blood flow rate is usually above 300 ml / minute. In other countries, the flow rate and treatment time are lower and longer, respectively.

[0005] Hemodialysis has a serious impact on the body's fluid balance, in part due to the rapid changes in circulating blood volume. When the dialysis fluid removal rate is faster than the plasma refill rate of the stored plasma maintained by the body's internal tissues, the intravascular blood volume decreases. The resulting imbalance is associated with complications similar to conventional blood loss, such as hypotension, loss of consciousness, headache, vomiting, dizziness, and cramps, that patients experience during and after dialysis treatment. Continuous quantitative measurement of parameters related to the handling of blood volume during hemodialysis (in real time) can reduce the chance of dialysis-induced hypotension and optimize dialysis treatment regimens by controlling fluid balance and helping patients reach target dry weight.

[0006] During hemodialysis treatment, the patient's blood is circulated outside the patient's body in order to filter out toxins via the dialyzer. Air in the blood line, whether retained there due to inadequate removal during perfusion or generated at the blood-air interface in the drip chamber, can cause clotting over time. Clotting reduces the effectiveness of the treatment and may require the blood to be discarded if blood flow stops. Therefore, heparin, a naturally occurring anticoagulant, can be steadily infused into the bloodstream via a pump in order to reduce the likelihood of clots. Summary of the invention

[0007] An embodiment of the present disclosure provides a method for monitoring blood coagulation. The method includes: circulating blood through an extracorporeal circuit through a dialysis system, wherein the blood flows from a patient to an input tube of the extracorporeal circuit, then flows to a dialyzer of the dialysis system, and then flows back to the patient via an output tube of the extracorporeal circuit; measuring the blood vibration frequency of the blood flowing through the extracorporeal circuit through an optical fiber sensor of the dialysis system; determining whether the blood vibration frequency is lower than a threshold value through the dialysis system; and in response to the blood vibration frequency being lower than the threshold value, performing a remedial process through the dialysis system to deal with blood coagulation.

[0008] Embodiments of the present disclosure provide a dialysis system for monitoring blood coagulation. The dialysis system includes: a pump for pumping blood from a patient through an extracorporeal circuit; a dialyzer connected to the extracorporeal circuit; an optical fiber sensor interfaced with the extracorporeal circuit, wherein the optical fiber sensor is configured to measure the blood vibration frequency at a location along the extracorporeal circuit; and a controller configured to: determine whether the blood vibration frequency is below a threshold, and execute a remedial process to address blood coagulation in response to the blood vibration frequency being below the threshold.

[0009] Embodiments of the present disclosure provide a non-transitory computer-readable medium storing computer-executable instructions for monitoring blood coagulation in a dialysis system. The computer-executable instructions, when executed, cause: circulating blood through an extracorporeal circuit; measuring a blood vibration frequency of blood flowing through the extracorporeal circuit; determining whether the blood vibration frequency is below a threshold; and in response to the blood vibration frequency being below the threshold, executing a remedial process to address blood coagulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a perspective view of a typical patient undergoing hemodialysis treatment, wherein the patient's blood is monitored in real time using a non-invasive optical blood monitor as the patient's blood passes through extracorporeal tubing in a hemodialysis system;

[0011] Figure 2 An exemplary system for performing hemodialysis according to some embodiments of the present disclosure is shown, showing a first position for a fiber optic sensor;

[0012] Figure 3 An exemplary optical fiber sensor according to some embodiments of the present disclosure is shown;

[0013] Figure 4 An exemplary system for performing hemodialysis according to some embodiments of the present disclosure is shown, showing a second position for a fiber optic sensor;

[0014] Figure 5 shows the use of two fiber optic sensors to measure the effect of heparin according to one embodiment of the present disclosure;

[0015] Figure 6 An exemplary system for performing hemodialysis according to some embodiments of the present disclosure is shown showing a first position for a fiber optic sensor and a clot neutralizer device;

[0016] Figure 7 shows the placement of an ultrasonic transducer for bursting a blood clot according to one embodiment of the present disclosure;

[0017] Figure 8 is a flow chart illustrating a process of clot neutralization using a fiber optic sensor according to some embodiments of the present disclosure;

[0018] Fig. 9 is a flow chart illustrating a process of clot neutralization using a fiber optic sensor according to some embodiments of the present disclosure; and

[0019] Fig.10 is a flow chart illustrating a process for monitoring clot neutralization effectiveness according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0020] Heparin is an expensive drug and overuse can be harmful to the patient's health, preventing clotting when disconnected from the patient at the end of his / her treatment. In addition, a problem in dialysis is estimating how much heparin to prescribe for any particular patient, some of which either goes to waste or treatment is delayed due to insufficient heparin. In addition, some patients are allergic to heparin, so alternatives such as saline may be used to break up blood clots with direct and expensive monitoring by the clinician.

[0021] Some embodiments of the present disclosure monitor clotting in real time and target those clots with precise heparin infusions. Monitoring is accomplished by using fiber optic sensors, and targeting of clots can be achieved by interpreting software linked to a heparin pump. The use of fiber optic sensors and software controlled heparin pumps can reduce the cost of hemodialysis treatments and prevent patients from suffering from overdosage of heparin, thereby improving health outcomes.

[0022] Some embodiments of the present disclosure monitor clotting in real time and target those clots using ultrasonic vibrations. When the fiber optic sensor detects that the blood cells are vibrating more slowly, the ultrasonic head can vibrate the clot before it reaches a critical size to burst the clot. The ultrasonic head generates sound waves at a frequency / wavelength that causes the blood cells to vibrate vigorously again, effectively breaking up the clot because the clot can no longer hold itself together.

[0023] Figure 1 is a perspective view of an exemplary patient undergoing hemodialysis treatment wherein a non-invasive optical blood monitor is employed to monitor the patient's blood in real time as it passes through extracorporeal tubing in a hemodialysis system. Figure 1 The environment shown in may be applicable to the exemplary embodiments of the present disclosure. In addition, it is understood that Figure 1 The environment shown in is merely exemplary, and the principles discussed herein for exemplary embodiments of the present disclosure may also be implemented in other environments.

[0024] Figure 1 A patient 10 is shown receiving hemodialysis treatment using a conventional hemodialysis system 12 and a non-invasive optical blood monitor 14. A typical hemodialysis clinic would have multiple hemodialysis systems 12 for treating patients on a Monday-Wednesday-Friday schedule or a Tuesday-Thursday-Saturday schedule. Although the present invention is not limited to the number of hemodialysis systems located at a clinic or to the specific type of hemodialysis system, the general operation of the hemodialysis system 12 is helpful in understanding the environment in which the present invention is intended to be used.

[0025] An input needle or catheter 16 is inserted into an access site of the patient 10, such as an arm, and is connected to an extracorporeal tube 18, which leads to a peristaltic pump 20 and then to a dialyzer or blood filter 22. The dialyzer 22 removes toxins and excess fluid from the patient's blood. The dialyzed red blood cell blood volume is returned from the dialyzer 22 via an extracorporeal tube 24 and a return needle or catheter 26. In certain areas of the world (primarily the United States), the extracorporeal blood flow may additionally receive a heparin drip to prevent clotting. Excess fluid and toxins are removed by a clean dialysis fluid, which is supplied to the dialyzer 22 via tube 28 and removed via tube 30 for disposal. In the United States, a typical hemodialysis treatment session takes approximately 3 to 5 hours.

[0026] exist Figure 1In the exemplary environment shown, the optical blood monitor 14 includes a blood chamber 32, an optical blood sensor assembly 34, and a controller 35. The blood chamber 32 can be positioned in series with the extracorporeal tube 18 upstream of the dialyzer 22. Blood from the peristaltic pump 20 flows into the blood chamber 32 through the tube 18. In some embodiments, the blood chamber 32 is not provided, and the optical blood sensor assembly 34 is directly coupled to the extracorporeal tube 18. The optical blood sensor assembly 34 may include a fiber optic sensor for measuring the vibration rate of individual blood cells.

[0027] Embodiments of the present disclosure incorporate fiber optic sensors into hemodialysis machines, such as hemodialysis system 12, and the fiber optic sensors can interpret how fast red blood cells coagulate. Using heterodyne amplification analysis, complex media such as blood can be analyzed to determine the vibration rate of individual cells in the bloodstream. Coagulation can be indicated by the vibration of blood cells, i.e., coagulation causes the cells to vibrate more slowly.

[0028] Figure 2 An exemplary system configuration 200 for hemodialysis treatment according to some embodiments of the present disclosure is shown. The system configuration 200 can include an optical sensor assembly 202 with a fiber optic sensor placed after a saline tube input device 204 and before a heparin tube input device 206. An example of a fiber optic sensor that can be used in the optical sensor assembly 202 includes a Baumer FSE 100F6Y01 sensor. The system configuration 200 can also include a bubble detector 208. The optical sensor assembly 202 is shown as being mounted directly below the arterial drip chamber. During hemodialysis, the optical sensor assembly 202 can monitor vibrations from the patient's blood to determine whether heparin should be infused using the heparin tube input 206 device.

[0029] Figure 3 An exemplary optical sensor assembly 300 is shown, which includes a container 314 with a transparent container wall 302, a transmitting optical fiber 306, a receiving optical fiber 308, a light source 312, and a photodetector 310. The container 314 can be a plastic tube or a glass chamber with a transparent container wall 302. The transmitting optical fiber 306 transmits light from the light source 312 to the container 314 for illuminating the blood flowing through the container 314. In one embodiment, the light source 312 provides light with a wavelength range of 635nm to 700nm. The blood cells 304 interact with the emitted light and reflect some of the light. The reflected light is received by the receiving optical fiber 308 and directed to the photodetector 310.

[0030] The light received at the photodetector is related to the spacing between the blood cells 304, which is indicative of the vibration characteristics of the blood cells 304. Coagulation causes the blood cells 304 to vibrate more slowly than non-coagulated blood cells 304, and therefore will have a higher amplitude of reflected light. For example, segment 316 will have a lower amplitude of reflected light when illuminated by the light source 312 than segment 318. In one embodiment, the light source 312 is a light emitting diode (LED), and the LED, the photodetector 310, the receiving optical fiber 308, and the transmitting optical fiber 306 comprise a fiber optic sensor of the fiber optic sensor assembly 300.

[0031] Figure 4 An exemplary system configuration 400 for hemodialysis treatment according to some embodiments of the present disclosure is shown. The system configuration 400 includes an optical sensor assembly 408 having a fiber optic sensor placed after a heparin tube input device 406. During hemodialysis, the optical sensor assembly 408 can monitor the vibrations of blood cells entering the patient to determine whether heparin should be infused using the heparin tube input device 406. Figure 4 In the embodiment, the optical sensor assembly 408 is placed in the IV clamp below the IV drip chamber 410 at the location of the existing bubble detector. The advantage of this location is that no new connection points are added to the clinician's workflow, and the optical sensor assembly 408 can be used to detect clots and bubbles, thereby simplifying and reducing the cost of incorporating clot monitoring functionality into the dialysis machine.

[0032] Figure 2 and Figure 4 Two placements of the optical sensor assembly are shown, one before the heparin tube input device 206 and one after the heparin tube input device 406. Other configurations with two fiber optic sensors may be used, where blood vibrations are measured before heparin infusion and blood vibrations are also measured after heparin infusion to determine the effect of the heparin infusion. Figure 5 An example of such a configuration is included that utilizes two optical components (optical component 502 and optical component 508) to monitor blood vibration before and after heparin. In one example, as Figure 5 As shown, before heparin infusion, optical assembly 502 can measure 50% of the red blood cell vibration, and after heparin infusion, optical assembly 508 can measure 65% of the red blood cell vibration. The 15% difference indicates the effect of heparin infusion via heparin tube infusion device 506. Heparin infusion is used as an example for discussion, but a similar process can also be used to determine the effect of saline infusion.

[0033] In some embodiments, software running on the hemodialysis system 12 can interpret blood cell vibrations and directly control the heparin pump to infuse heparin. Control of the heparin pump using the software can reduce the use of heparin, which is conducive to preloading a smaller amount of heparin into the hemodialysis system 12. In addition, if the hemodialysis system 12 anticipates a higher likelihood of clotting or more frequent clotting based on vibration monitoring, the hemodialysis system 12 can notify the clinician whether the remaining heparin is too low to continue. This notification can take the form of generating an alarm.

[0034] In some embodiments, the hemodialysis system 12 monitors feedback from the fiber optic sensor and creates a model of how the vibration rate of the blood cells changes through subsequent cycles in the extracorporeal blood circuit. For example, for a given blood pump rate and the patient's total blood volume, the hemodialysis system 12 estimates the recirculation time, that is, the time it takes before the hemodialysis system 12 processes the same blood again. According to one embodiment of the present disclosure, the hemodialysis system 12 uses an optical sensor assembly to make an initial red blood cell vibration measurement D1 at time t0. After the recirculation time, the hemodialysis system 12 makes another measurement D1 at time t1. The interval between time t1 and t0 is the recirculation time, and subsequent measurements D1 are made at intervals of the recirculation time. n .

[0035] After multiple measurements, the hemodialysis machine 12 determines the patient's vibration variation characteristics based on the patient's hematocrit, blood flow rate, and temperature. n Both are cross-checked with D0 and D1, producing an effect in the form of an increasing slope showing the increase in red blood cell vibration over time. In one embodiment, an ultrasonic sensor operating at a very high frequency (>65 MHz) can be used to measure the white blood cell count when creating a model of how the vibration rate of the red blood cells changes through subsequent cycles. In this way, as the white blood cells fluctuate from one dialysis treatment session to another, the model created during the dialysis session or the changing characteristics can be adjusted based on the white blood cell count.

[0036] In one embodiment, the hemodialysis system 12 can make suggestions to the clinician based on the blood vibration measurement results during dialysis. For example, if the hemodialysis system 12 determines that the blood vibration measurement result is low, the hemodialysis system 12 can suggest that the clinician infuse 200ml of normal saline (NS) or 1ml of heparin into the extracorporeal circuit. In one embodiment, instead of reminding the clinician, when the hemodialysis system 12 determines that the blood vibration measurement result is low, the clinician can set the hemodialysis system 12 to automatically infuse an appropriate heparin dose. In one embodiment, the hemodialysis system 12 provides visual and / or audible alarms to the clinician with suggestions. The hemodialysis system 12 may include a speaker for providing an audio alarm. The hemodialysis system 12 may include multiple displays for providing visual alarms, such as displays on an optical blood monitor 14.

[0037] In one embodiment, the hemodialysis system 12 automatically and periodically adjusts the temperature of the dialysate, for example, to make the blood cells more viable, thereby further reducing the use of heparin. For example, when the blood vibration measurement result is low, the hemodialysis system 12 increases the dialysate temperature in steps of 0.25 degrees Celsius, up to a maximum of 37.5 degrees Celsius, before alerting the clinician with a visual and / or audible alarm.

[0038] In one embodiment, the hemodialysis system 12 associates feedback from a combined sensor, such as a Crit-Line hematocrit sensor, to prompt the clinician to infuse saline rather than use more heparin when approaching dry weight before the end of the dialysis treatment time. For example, the goal of dialysis is to have the patient reach dry weight within the set dialysis treatment time, so during the last half hour of treatment, the hemodialysis system 12 only infuses saline or reminds the clinician to infuse only saline when needed. In this way, during the last half hour of treatment, no heparin is used at all. The hemodialysis system 12 can use the treatment time that has passed since the start of treatment or the combined sensor's indication of blood volume changes to determine when to use only saline.

[0039] Figure 6An exemplary system configuration 600 for hemodialysis treatment according to some embodiments of the present disclosure is shown. The system configuration 600 may include an optical sensor assembly 602 having a fiber optic sensor and an ultrasonic head or a piezoelectric head placed downstream after a saline tube input device 604. The ultrasonic head that can be used includes a high-frequency transducer designed to produce a frequency of at least 50 MHz, such as an NDT Instrument U841102 transducer. In some embodiments, a laser vibrometer, such as a PolyTec CLV-2534 compact laser vibrometer, can be used as a fiber optic detector. When the fiber optic sensor detects that the blood cells are vibrating more slowly, the hemodialysis machine may activate the ultrasonic head to burst the clot before the clot reaches a critical size. The ultrasonic head generates sound waves at a wavelength that causes the blood cells to vibrate violently again, thereby effectively breaking up the clot because it can no longer hold itself together. For example, the ultrasonic head can generate sound waves at 65 MHz to break up the clot. By eliminating the need for heparin or a heparin pump on the hemodialysis machine 12, the system configuration 600 can greatly reduce the cost of treatment.

[0040] Although in some embodiments an ultrasonic head is provided for breaking up clots or bursting clots before they reach a critical size, other methods of agitating the blood may also be used. For example, a vibration motor may be placed on the tube, and the hemodialysis machine 12 may turn on the vibration motor to agitate the tube in order to break up clots detected via the fiber optic sensor.

[0041] In one embodiment, the ultrasound head may be used to locally detect clots or clumps of red blood cells between 20 μm and 100 μm at a lower frequency, such as 50 MHz, and may then be used to break up the clots at a slightly higher frequency, such as 65 MHz.

[0042] Figure 7 An ultrasonic head configuration according to one embodiment of the present disclosure is shown. The ultrasonic head 702 is placed at an angle to the container 704. The ultrasonic head 702 generates ultrasonic waves 706 for breaking up clots in the blood flowing through the container 704.

[0043] In some embodiments, software in the hemodialysis system 12 can be used to interpret blood cell vibrations and directly control the ultrasonic head. According to an embodiment of the present disclosure, the hemodialysis system 12 monitors feedback from the fiber optic sensor and creates a model of how the vibration rate of the blood cells changes through subsequent cycles in the extracorporeal blood circuit. The hemodialysis system 12 can then make recommendations to clinicians. For example, if coagulation becomes too common due to system leakage, the hemodialysis system 12 can alert the clinician in the form of a pop-up or status box message to provide an emergency manual push of heparin. In one embodiment, if the vibration of the blood cells drops below the expected threshold, the hemodialysis system 12 determines that coagulation is detected and automatically infuses a certain amount of saline into the extracorporeal circuit. The hemodialysis system 12 incorporates the added volume of saline into the ultrafiltration target of the dialysis treatment.

[0044] Figure 8 FIG. 8 is a flow chart illustrating a process of clot neutralization using a fiber optic sensor in a hemodialysis machine 12 according to some embodiments of the present disclosure. In step 802, the fiber optic sensor measures the blood vibration frequency. For example, Figure 3 In the embodiment of the present invention, the fiber optic sensor may include a light source 312, a photodetector 310, a receiving optical fiber 308, and a transmitting optical fiber 306. The light source 312 illuminates the fluid flowing through the tube. The fluid, such as blood, flowing through the tube of the dialysis circuit is deflected in the tube. The fluid also causes the light emitted from the transmitting optical fiber 306 to reach the receiving optical fiber 308 attenuated in a manner proportional to the flow rate of the fluid in the tube. The hemodialysis machine 12 determines the flow rate based on the light received at the photodetector 310.

[0045] The hemodialysis machine 12 can then determine the blood vibration frequency by calculating the potential energy of the blood at rest (e.g., blood in a vial) and the kinetic energy of the blood at the measured flow rate. The hemodialysis machine 12 can determine the mass of the blood based on the hematocrit measured using, for example, a Crit-Line sensor. Based on the mass and flow rate, the hemodialysis system 12 uses 1 / 2×mass×velocity 2 The kinetic energy is determined, where the velocity is the measured flow rate. The kinetic energy is measured, for example in Joules, as the blood vibration frequency.

[0046] At step 804, the blood vibration frequency is compared to a threshold value. The threshold value may be different for each patient and may be calibrated on a per patient basis. The threshold value may be affected by the blood pump rate, performance of the access flow, hematocrit, temperature, and white blood cell percentage. Each patient is tested and calibrated in advance to determine the patient's threshold value.

[0047] In one embodiment, since blood vibration frequency and temperature are correlated, blood temperature can be used as an upper threshold limit. The blood temperature is monitored by the hemodialysis system 12 using a temperature sensor so that it does not exceed 39 degrees Celsius.

[0048] At step 806, when the blood vibration frequency is below the threshold of step 804, the hemodialysis machine 12 performs a remedial process, which may include adjusting the operation of the hemodialysis machine 12. In one aspect, the hemodialysis machine 12 may control the heparin pump, as described above in conjunction with Figure 4 As described, when the blood oscillation frequency falls below a threshold, heparin is infused.

[0049] In another aspect, the hemodialysis machine 12 can control the ultrasonic head to generate sound waves to agitate the blood so as to increase the blood vibration frequency. For example, if the blood vibration frequency measured at step 802 is lower than the threshold value at step 804, coagulation is detected. The hemodialysis machine 12 can provide a signal to instruct the ultrasonic head to emit a series of short ultrasonic bursts at an empirically determined frequency. In one embodiment, the short ultrasonic burst is on the order of milliseconds because blood moves through the tube at a speed of up to 500 ml / min during dialysis, which will cause clots to pass quickly through the ultrasonic head.

[0050] A second vibration sensor, such as a fiber optic sensor, placed downstream of the ultrasound head can be used to verify whether the clot has broken down. Since the blood flow rate through the extracorporeal circuit is known, the second vibration sensor can measure coagulation at a specific time after emitting a series of short ultrasound bursts.

[0051] The use of an ultrasonic head to break up clots can follow a variety of algorithms determined through testing using a feedback monitoring loop in a laboratory setting. For example, the ultrasonic head can emit a constant low frequency in the range of 20 Hz to "stir" the red blood cells so that they cannot form clots. In another example, the ultrasonic head can emit a series of short bursts at 50 MHz to break off long chains of red blood cells.

[0052] In another aspect, when the blood vibration frequency is below the threshold, the hemodialysis machine 12 can sound an alarm. Multiple types of alarms can be set, for example, if the treatment is close to termination, an alarm can be set for the clinician to infuse saline instead of heparin. Another alarm can be set to prompt the clinician for an emergency manual push of heparin. Another alarm can be set to prompt the clinician to increase the temperature of the dialysate used during the hemodialysis treatment or reduce the blood pump rate.

[0053] Fig. 9 is a flow chart illustrating a process 900 for clot neutralization using a fiber optic sensor according to some embodiments of the present disclosure. Fig. 9Shows Figure 8 In step 902, the hemodialysis machine 12 uses the fiber optic sensor to measure the blood vibration frequency. In step 904, the hemodialysis machine 12 determines whether the blood vibration frequency is below a threshold. If the blood vibration frequency is above the threshold, then in step 902 the hemodialysis machine 12 continues to measure the blood vibration frequency. If the blood vibration frequency is below the threshold, then the hemodialysis machine 12 performs a remedial process (e.g., by taking Fig. 9 one or more of the five pathways depicted in ).

[0054] In the first path, at step 906, the hemodialysis machine 12 determines the remaining treatment time. At step 908, the hemodialysis machine determines whether the patient is close to dry weight based on the remaining treatment time or based on the hematocrit as described above. At step 910, if the remaining treatment time is below a threshold, such as 30 minutes, and / or if the dialysis patient is close to dry weight, the hemodialysis machine 12 only infuses saline into the blood circuit. The volume of the added saline can be a preset amount (e.g., between 10ml and 500ml). The preset amount can be selected by an authorized user of the hemodialysis machine (e.g., in the service mode of the machine). The preset amount can also be based on the remaining treatment time (e.g., 200ml for 30 minutes remaining, 150ml for 20 minutes remaining, 100ml for 10 minutes remaining, and 50ml for 5 minutes or less remaining).

[0055] In the second path, if the blood vibration frequency is below the threshold at step 904, the hemodialysis machine 12 infuses saline into the blood circuit at step 912. The volume of saline added may be a pre-set amount determined in a manner similar to that described above.

[0056] In the third path, if the blood vibration frequency is lower than the threshold value in step 904, then in step 914, the hemodialysis machine 12 infuses heparin into the blood circuit. The volume of the added heparin can be a preset amount (e.g., between 0.5ml and 1.5ml). The preset amount can be selected by an authorized user of the hemodialysis machine (e.g., in the service mode of the machine). The preset amount can also be based on the remaining treatment time (e.g., 1.5ml for 3 hours remaining, 1ml for 2 hours remaining, 0.5ml for 1 hour remaining, and 0.25ml for 30 minutes remaining, and no heparin infusion for less than 30 minutes remaining mark). In addition, the hemodialysis machine 12 can be configured to wait for a certain time before any additional heparin is infused after a certain amount of heparin is infused, to ensure that the first infusion has time to take effect (e.g., the machine may include a requirement of waiting at least 1 hour between heparin infusions).

[0057] In the fourth path, according to an embodiment of the present disclosure, if the blood vibration frequency is below the threshold value at step 904, then at step 916, the hemodialysis machine 12 uses the ultrasonic head to agitate the blood in the blood circuit using ultrasound. The agitation process may include a short burst (e.g., lasting a few microseconds) for the detected clot. The timing of the burst may be based on the position of the ultrasonic head relative to the fiber optic sensor and the blood flow rate (e.g., the blood pump rate may be 10-600 ml / min). In addition, the hemodialysis machine 12 is able to distinguish between re-detecting the same clot and detecting a new clot based on the blood recirculation time (calculated based on the blood pump rate), so that the hemodialysis machine 12 can determine whether the agitation process can successfully break up the blood clot.

[0058] In the fifth path, if the blood vibration frequency is below the threshold at step 904, the hemodialysis machine 12 generates an audio / visual alert for the clinician at step 918. In some embodiments, any of the other paths are utilized to perform step 918. For example, the hemodialysis machine 12 may indicate that a certain amount of heparin is being added in response to the blood vibration frequency being below a threshold, and may further alert the clinician if clotting is still sensed even after the heparin is added.

[0059] Fig.10 1 is a flow chart showing a process 1000 for monitoring clot neutralization effects according to some embodiments of the present disclosure. In step 1002, the hemodialysis machine 12 uses a fiber optic sensor to measure the blood vibration frequency. In step 1004, the hemodialysis machine 12 determines whether the blood vibration frequency is below a threshold. In step 1006, according to an embodiment of the present disclosure, when the blood vibration frequency is below the threshold, the hemodialysis machine 12 performs a remediation process, wherein the remediation process includes adjusting the operation of the hemodialysis machine 12.

[0060] At step 1008, the hemodialysis machine 12 measures the blood vibration frequency, and at step 1010, the hemodialysis machine 12 determines the effect of the adjustment based on the adjustment made at step 1006. For example, the hemodialysis machine 12 may determine the effect of heparin infusion as previously described. In one embodiment, the effect of saline infusion is determined using a similar process as used to determine the effect of heparin infusion.

[0061] At step 1012, the hemodialysis machine 12 determines whether the effect of the adjustment at step 1010 is comparable to the expected effect. For example, if the adjustment is a heparin infusion, the expected effect may be a calibrated measure of the expected response of the patient's blood to the measured dose of heparin.

[0062] In some embodiments, the expected effect is the expected minimum response regardless of the adjustment technique, i.e., any adjustment performed at step 1006 should record at least the minimum response. At step 1012, the hemodialysis machine 12 may determine whether the adjustment effect is greater than or equal to the expected effect. The expected effect is measured as a percentage increase in the blood oscillation frequency.

[0063] If the adjustment is comparable to the expected effect, then at step 1002, the hemodialysis machine 12 measures the blood vibration frequency at step 1002. If the adjustment is not comparable to the expected effect, then the hemodialysis machine 12 may perform at least one of steps 1014 and 1018.

[0064] At step 1014, the hemodialysis machine 12 determines whether the adjusted reserve for the remaining treatment time is low. For example, the hemodialysis machine 12 may determine whether there is sufficient saline and / or heparin reserve to complete the dialysis treatment based on the remaining treatment time. If the adjusted reserve is insufficient to complete the hemodialysis treatment, then at step 1016, the hemodialysis machine 12 may generate an alarm to alert the clinician of the low reserve condition.

[0065] If the adjustment effect is not comparable to the expected effect or is not greater than the minimum effect at step 1012, the hemodialysis machine 12 selects an alternative adjustment technique or changes the adjustment dosage at step 1018. For example, the hemodialysis machine 12 may switch from using an ultrasonic head to saline, or may switch from saline to heparin, etc. The hemodialysis machine 12 may have stored dosages of saline and heparin, and may have stored settings for activating the ultrasonic head in a constant low frequency mode or a high frequency burst mode. The hemodialysis machine 12 may automatically change the settings of a particular adjustment or select an alternative adjustment.

[0066] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0067] In the context of describing the present invention (particularly in the context of the appended claims), the use of the terms "one", "said" and "at least one" and similar references should be interpreted as including both the singular and the plural, unless otherwise specified herein or clearly contradicted by the context. The use of the term "at least one" followed by a list of one or more items (e.g., "at least one of A and B") should be understood to refer to an item (A or B) selected from the listed items or any combination of two or more of the listed items (A and B), unless otherwise specified herein or clearly contradicted by the context. Unless otherwise specified, the terms "containing", "having", "including" and "comprising" should be interpreted as open terms (i.e., meaning "including but not limited to"). Unless otherwise specified herein, the description of the range of values ​​herein is intended only to be used as a shorthand method for referring to each individual value falling within the range, respectively, and each individual value is incorporated into the specification as if it were individually narrated herein. Unless otherwise specified herein or clearly contradicted by the context, all methods described herein can be performed in any suitable order. Unless otherwise stated, the use of any and all examples or exemplary language (e.g., "such as") provided herein is intended only to better illustrate the present invention and does not limit the scope of the present invention. No language in the specification should be construed as indicating that any non-claimed element is essential to the practice of the present invention.

[0068] Preferred embodiments of the present invention are described herein, including the best mode known to the inventor for implementing the present invention. By reading the foregoing description, variations of those preferred embodiments will become apparent to those of ordinary skill in the art. The inventor expects that skilled technicians will appropriately adopt such variations, and the inventor wishes to practice the present invention in a manner different from that specifically described herein. Therefore, the present invention includes all modifications and equivalents of the subject matter recorded in the appended claims as allowed by applicable law. In addition, unless otherwise noted herein or clearly contradictory to the context, the present invention encompasses any combination of the above-mentioned elements in all possible variations thereof.

Claims

1. A dialysis system for monitoring blood coagulation, comprising: a pump for pumping blood from a patient through an extracorporeal circuit; a dialyzer connected to an extracorporeal circuit; a first fiber optic sensor interfaced with the extracorporeal circuit upstream of the heparin tube connected to the extracorporeal circuit, wherein the first fiber optic sensor is configured to measure a first blood vibration frequency at a location along the extracorporeal circuit; a second fiber optic sensor interfaced with the extracorporeal circuit downstream of the heparin tube, wherein the second fiber optic sensor is configured to measure a second blood vibration frequency of blood flowing through the extracorporeal circuit; and A controller is configured to determine a heparin effect based on the first blood vibration frequency and the second blood vibration frequency, and to perform a remedial process to address blood clotting based on the heparin effect.

2. The dialysis system according to claim 1, wherein Executing the remediation process involves: An alarm is generated to alert the clinician, the alarm including a visual and / or audible signal.

3. The dialysis system according to claim 1, wherein: Executing the remediation process involves: A signal for dispensing saline in the extracorporeal circuit is provided via a saline tube connected to the extracorporeal circuit.

4. The dialysis system according to claim 1, wherein: Executing the remediation process involves: The signal for dispensing heparin in the extracorporeal circuit is provided via the heparin tube.

5. The dialysis system according to claim 1, wherein The dialysis system further comprises: An ultrasound head is provided at the interface with the extracorporeal circuit downstream of the position where the first optical fiber sensor is provided at the interface with the extracorporeal circuit, and the ultrasound head is configured to emit sound waves for agitating the circulating blood.

6. The system according to claim 5, wherein: The frequency of the sound wave is above 50 MHz, and the sound wave is emitted in a burst.

7. A non-transitory computer-readable medium storing computer-executable instructions for monitoring blood clotting in a dialysis system, wherein: The computer executable instructions, when executed, cause: circulating blood through the extracorporeal circuit using a pump for pumping blood from the patient through the extracorporeal circuit, wherein a dialyzer is connected to the extracorporeal circuit; measuring a first blood vibration frequency of blood flowing through the extracorporeal circuit using a first fiber optic sensor, the first fiber optic sensor being interfaced with the extracorporeal circuit upstream of a heparin tube connected to the extracorporeal circuit and being configured to measure the first blood vibration frequency at a location along the extracorporeal circuit; measuring a second blood vibration frequency of blood flowing through the extracorporeal circuit using a second fiber optic sensor interfaced with the extracorporeal circuit downstream of the heparin tube, the second fiber optic sensor being configured to measure the second blood vibration frequency of blood flowing through the extracorporeal circuit; Using a controller, a heparin effect is determined based on the first blood vibration frequency and the second blood vibration frequency, and a remedial process is performed to address blood clotting based on the heparin effect.

8. The non-transitory computer-readable medium of claim 7, wherein: Executing the remediation process involves: An alarm is generated to alert the clinician, the alarm including a visual and / or audible signal.

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