Device for extracorporeal blood treatment with automatic respiratory rate monitoring

Abstract

Device (10) for extracorporeal blood treatment, in particular a dialysis device (10) which includes a radar sensor (17) for monitoring a patient (P) located at a treatment station, at least one shut-off device (13, 30) for shutting off a line (23) connected venously to the patient (P) and / or for shutting off an arterial line (22) connected to the patient (P), in particular in the form of a hose clamp (30) clamping an elastic or flexible area of ​​the line (22, 23), a blood pump and has a control unit (14), wherein the control unit (14) is set up and configured to determine a patient's (P) respiratory rate and / or respiratory amplitude based on signals from the radar sensor (17) and to trigger an alarm signal if the respiratory rate and / or respiratory amplitude detected by the radar sensor (17) deviates from one or more preset limit values, the shut-off device (13, 30) can be automatically operated via the control unit (14) in the event of an alarm and The blood pump is stopped in case of an alarm.

Description

[0001] The invention relates to a device for extracorporeal blood treatment with a system for detecting needle disconnections. In particular, the invention relates to a medical device in which blood loss can occur in the patient due to leaks in the extracorporeal circuit or errors in patient access. Background of the invention

[0002] Medical devices for extracorporeal blood treatment typically include a blood treatment unit, such as a dialyzer, which is connected to a patient's bloodstream via extracorporeal lines. These devices also include a blood pump and a control unit for regulating the pump and monitoring its operating status. A typical treatment performed with such devices is dialysis, which is usually carried out in dedicated facilities. These facilities typically have 20 to 50 treatment stations distributed across several rooms. Nursing staff are responsible for monitoring patients during treatment. However, a disadvantage is that it cannot be guaranteed that a nurse will always be present to monitor a patient, as one nurse is usually responsible for several patients.Therefore, efforts are underway to transfer at least part of patient monitoring to the medical device, thereby enabling the detection of risks to the patient, the implementation of appropriate safety measures, and the summoning of nursing staff. However, in the event of extracorporeal blood loss due to a disconnection in the venous return, patient safety is currently only ensured through careful monitoring by nursing staff, as a commonly used venous pressure monitoring system is not capable of reliably detecting blood loss in every case.

[0003] In extracorporeal blood therapy, such as hemodialysis or plasma exchange, a patient's blood flows from an arterial access point through a filter to a venous access point. An arteriovenous fistula is often surgically created to access the vascular system, generally using a double-needle and arterial cannula. The use of a vascular graft (shunt) is also possible. Vascular access refers to any type of access to the patient's vascular system, but especially to a connection between the patient's artery and vein. Currently, there is no reliable device to prevent blood loss, particularly with double-needle access. To prevent needle dislodgement, the lines leading to or from the vascular access are currently sealed with adhesive tape.Furthermore, conventional dialysis machines measure the flow resistance between the machine and the patient during blood return. The blood is pumped through the cannula into the patient at a rate of 200 to 600 ml / min. The flow resistance of the cannula alone largely falls within the pressure monitoring range of the dialysis machine. If the venous cannula slips out, blood from the arterial access flows through the dialysis machine and out of the patient. The dialysis machine reacts due to secondary influences such as the pressure drop at the venous pressure sensor. However, this pressure drop depends on the blood flow, hematocrit, cannula, and the patient's venous pressure. Normally, the nursing staff sets a lower limit as close as possible to the current venous pressure, without knowing the exact pressure that will likely occur if the cannula slips out.In principle, two possibilities arise: either the dialysis machine sounds an alarm without the cannula having slipped out, thus calling the nursing staff to the machine, or the dialysis machine does not sound an alarm when the cannula has slipped out and the patient loses blood.

[0004] Prior art includes approaches for controlling machines used in extracorporeal blood therapy. For example, patent application US 2015 0253860 A1 describes controlling a dialysis machine using an electric field, where the machine can be controlled by a user's gestures. Similarly, EP 2 857 053 describes capturing gestures within the detection range of a motion detection device to control a dialysis machine, for example, using a camera and a cameraless sensor. DE 10 2006 060 819 A1 describes a dialysis machine in which information about the respiratory rate is further used for dialysis treatment.

[0005] Furthermore, numerous different methods and devices for the general monitoring of patients' vital parameters are known. For example, US 2007 0118054 A1 discloses a method and system for monitoring vital parameters, in which, for example, respiration is recorded to detect different breathing patterns. A sensor is placed under the patient and can then detect corresponding patterns. These serve to monitor vital functions for the prediction and treatment of physiological disorders such as asthma, hypoglycemia, cough, edema, sleep apnea, and REM sleep phases. US 2008 0269589 A1 describes a portable radar sensor that transmits a radar signal into the chest and receives the reflected signal. The device is used to measure and monitor mechanical cardiac activity. US 4,958,638 A describes a radar technology with a range of approximately...The device can measure a patient's heart and respiratory rate from a distance of 6 meters. This non-contact vital signs monitor is used to support therapies in hospitals and nursing homes. US Patent 3,483,860 describes a method for measuring a patient's respiratory rate without radar technology, using a transmitting sensor above and a receiving sensor below the patient.

[0006] Furthermore, approaches for monitoring a patient during extracorporeal blood treatment are known. A general approach is disclosed in EP 1 574 178 A1, namely in the form of a medical treatment system in which a video camera is directed at a treatment station. The image from the video camera is displayed on the screen of a remotely located physician's station. In this way, the physician can visually see and monitor the patient. A disadvantage is that continuous monitoring is not possible and only a few patients can be monitored simultaneously. Another use of a camera is described in EP 1 892 001 A1, in which a camera is directed at a dialysis treatment station.The camera image is processed by a computing unit integrated into the dialysis machine. This unit determines the color of blood and / or its arrangement within the image, as well as the size of the captured area in relation to the blood color. In this way, extracorporeal blood loss can be automatically detected, signaled, and the blood pump stopped. A disadvantage of this method is that cameras without additional measures (such as infrared detection) only function during the day, i.e., in ambient light, and the resulting camera images contain personal data. Therefore, maintaining anonymity requires additional measures.

[0007] For the detection of blood loss during extracorporeal blood therapy, a prior art document, for example, WO 99 / 24145 A1, describes a pair of electrodes that are attached near a cannula during dialysis and connected to the dialysis machine by two leads. If the needle slips out of the patient, the flowing blood creates a conductive connection between the electrodes. This is detected by the dialysis machine. The dialysis machine's control system stops the blood flow and alerts the staff. A disadvantage of this method is the need for additional handling procedures that must be performed carefully by the staff. Furthermore, false alarms can occur if other fluids, such as sweat, accumulate between the electrodes. WO 01 / 47581 A1, which discloses a similar arrangement of electrodes for extracorporeal blood therapy, is also a prior art document.These devices are used to detect blood loss by capacitively coupling current between arterial and venous lines using a generator. The voltage drop caused by the current flowing through the blood in the line is then measured. If a cannula slips out, the current decreases, which is detected. A disadvantage of this method is that a needle that has not fully slipped out is not detected. DE 198 48 235 C1 discloses a system that evaluates arterial and venous pressure to detect the slippage of a venous cannula. A disadvantage of this method is that it incorporates the dynamic behavior of the extracorporeal circulation, which can lead to misinterpretations. Furthermore, the method does not solve the problem of indirectly measuring blood loss, as extracorporeal pressure is not a measure of blood loss. WO 03 / 86506 A1 describes an electrical contact that is inserted directly into the blood.Constant current and voltage drop analysis are used to detect whether the cannula has slipped out. A disadvantage of this method is that a cannula that has not fully slipped out will not be detected, and the tubing system is also expensive due to the need for electrical contacts.

[0008] The emergency physician guide by Berndebach, Luca (7th, completely revised edition. Basel: EMH Swiss Medical Publishers, 2013. pp. 115-119. - ISBN 978-3-03754-064-0) deals with different classes of shock and, in addition to other characteristics, lists typical respiratory rate ranges for different amounts of blood loss.

[0009] Based on the prior art described above, the present invention aims to eliminate the aforementioned disadvantages, in particular to design a medical device with extracorporeal blood circulation in such a way that excessive blood loss of a patient during treatment is detected with high certainty.

[0010] According to the invention, this problem according to claim 1 is solved by a device for extracorporeal blood treatment, in particular a dialysis device, comprising a radar sensor for monitoring a patient located at a treatment station, at least one shut-off device (13, 30) for shutting off a line (23) connected venously to the patient (P) and / or for shutting off an arterial line (22) connected to the patient (P), in particular in the form of a hose clamp (30) clamping an elastic or flexible section of the line (22, 23), and a control unit (14), wherein the control unit (14) is configured and designed to determine the respiratory rate of the patient (P) based on signals from the radar sensor (17) and to trigger an alarm signal if the respiratory rate detected by the radar sensor (17) deviates from a preset limit value or several preset limit values, and the shut-off device (13,30) in the event of an alarm, it can be automatically activated via the control unit (14). According to the invention, the device, together with an evaluation unit for signals from the radar sensor, forms a system for detecting the respiratory rate and / or respiratory amplitude of a patient. The evaluation unit can be designed separately from the device for extracorporeal blood treatment or integrally with it. The radar sensor is directed or can be aligned towards the treatment area or the patient located thereon. According to the invention, the radar sensor emits signals and receives the signals reflected by the patient. The information about the patient's condition contained in the received signals is evaluated by the evaluation unit.

[0011] According to the invention, the evaluation unit to which the radar sensor delivers its information can in particular perform one or more of the following processes: - Localization and / or detection of one or more patients, in particular the detection and / or recognition and / or monitoring of movements of the patient's chest. - Converting a detected chest movement into respiratory rate and / or amplitude. - Comparing the recorded respiratory rate values ​​and / or amplitude values ​​with at least one previously defined limit value, if applicable. - Stopping the blood pump and closing at least one hose clamp when the limit value is exceeded and / or fallen below. - Triggering an alarm if the limit value is not met, for example, if there is a deviation from a value of twelve to 18 breaths / minute and / or more than 20 breaths / minute (tachypnea) and / or less than 10 breaths / minute (bradypnea).

[0012] In summary, according to the invention, the evaluation unit is in particular set up and designed for comparing the recorded respiratory rate values ​​and / or amplitude values ​​with limit values ​​and the actions derived therefrom, namely stopping the blood pump and closing the hose shut-off clamp when the limit value is exceeded and / or not reached and / or giving an alarm.

[0013] Advantages of the invention compared to known prior art solutions for detecting venous needle disconnection include, in particular, non-contact monitoring of respiration to assess the patient's general condition or to provide feedback on problems during dialysis. In the case of nocturnal dialysis, effective monitoring of the patient's condition is possible, and monitoring can generally be performed anonymously. Additional vital parameters, such as fainting due to hypotensive episodes, can also be detected non-contact.

[0014] Advantageous embodiments of the invention are claimed in the dependent claims and are explained in more detail below.

[0015] A preferred embodiment of the invention provides that the radar sensor is directly integrated into the device. This has the advantage that the device can be used portably and that connecting the radar sensor to the device and its control system is particularly easy. It can be integrated into the device using conventional means, for example, with an IV pole or similar attached to the device. Preferably, the radar sensor is positioned on the device.

[0016] Preferably, the device has a reference marker that can be attached to the patient, particularly to their chest. This marker interacts sensibly with the radar sensor, meaning that the radar sensor can detect both the reference marker itself and its position and / or changes in position relative to the sensor. As a result of the reference marker being coupled to the patient, reliable detection of relative movements of the patient or specific body areas (chest) to the sensor is possible, allowing the patient's respiratory rate to be recorded easily and comfortably. The reference marker can, for example, be designed as a tag or button and attached to a target area, such as the patient's chest. According to a further embodiment of the invention, an alarm can be triggered if the reference marker is not located.

[0017] According to the invention, the device has at least one shut-off device for isolating a venous line connected to the patient. Alternatively or additionally, the device has at least one shut-off device for isolating an arterial line connected to the patient. The respective shut-off device can, in particular, be designed in the form of a hose clamp that clamps an elastic or flexible section of a blood line of the device or of an extracorporeal tubing system. In the event of a needle disconnection, this ensures rapid disconnection / shut-off of the tubing system from the patient, thus minimizing blood loss.

[0018] The device also features a control unit configured to determine the patient's respiratory rate based on signals from the radar sensor. This allows for simple, automated, and continuous monitoring of the patient's respiratory rate, ensuring a particularly high level of safety. Specifically, the control unit is configured to trigger an alarm if the respiratory rate detected by the radar sensor deviates from one or more preset limits (either above or below). For example, an alarm can be triggered if an elevated respiratory rate (e.g., more than 20 breaths per minute) is detected for a defined period (e.g., 30 seconds). In the event of an alarm, the shut-off valve can be automatically activated via the control unit.

[0019] In a preferred embodiment of the invention, a blood detector can be provided in the extracorporeal tubing system, which only allows activation of the radar monitoring if blood is detected. This blood detector is, for example, a red detector that detects a red fluid in the device's tubing system or in a hose system. This embodiment offers the advantage that radar monitoring is only performed when the patient is connected to the extracorporeal tubing system and blood is flowing into it.

[0020] A preferred embodiment of the invention provides that the radar sensor can be positioned / aligned by means of a drive, preferably automatically, for readjustment, in particular for automatic readjustment, of the radar sensor's alignment relative to the patient. This allows for a particularly comfortable and easy adjustment of the device for the patient. Furthermore, the drive ensures that the radar sensor detects the correct target area. The drive can, in particular, be an integral part of the radar sensor or the device.

[0021] According to one embodiment of the invention, information can be transmitted from the radar sensor to the evaluation unit via cable or via a wireless connection, for example via WLAN, Bluetooth, or similar technologies. It is also possible to provide multiple radar sensors that monitor the target area from different directions.

[0022] According to one embodiment of the invention, the device can include a reading device that is configured and suitable for capturing the identification of an operator, for example, a machine-readable employee ID card. The data of this identification is stored, thus documenting which person operated the device at what time and which settings were changed. Reading the identification can indicate that a caregiver is present at the treatment station. This can be used to evaluate signals indicating the patient's condition. For example, the previous respiratory rate can be used as a reference value, so that only changes that have occurred since the arrival of the caregiver are recorded.

[0023] The invention is explained in more detail below with reference to exemplary, non-limiting embodiments shown in the attached figures. These show: Fig. 1. A perspective view of the device in the form of a device for hemodialysis, hemofiltration or plasma treatment and Fig. 2. A schematic representation of the essential functional parts of the dialysis machine.

[0024] Fig. Figure 1 shows an embodiment of the device 10 according to the invention in the form of a medical device 10 for extracorporeal blood treatment. This device has a base 11 in which mechanical components, such as tubing, valves, etc., which are not shown in the figure, are located. At its front, the base 11 carries a console 12 in which two externally accessible blood pumps 13 are arranged. The blood pumps 13 are designed as peristaltic pumps, the tubing of which, which is not shown in the figure, is inserted from the front in a generally known manner.

[0025] On the device base 11 is a control unit 14, which forms an interface for communication with a user. The control unit 14 features a touchscreen monitor through which the user can access various menus, query operating states, and enter data and commands. A card reader 15 is provided, into which the user can insert a machine-readable identification card.

[0026] A radar sensor 17 is attached to a pole or infusion pole 16, which is preferably mounted on the device base / housing 11. In the present embodiment, radar images acquired by the radar sensor 17 are transmitted wirelessly to the control unit 14. The radar sensor 17 is directed towards a patient location (not shown) near the device 10, e.g., a couch on which the patient lies during blood treatment. In this way, the patient is detected by the radar sensor 17. It should be noted that the radar sensor 17 can also be mounted directly on the device base / housing 11.

[0027] The patient is connected to device 10 in the usual manner via tubes of an extracorporeal blood tubing system (not shown).

[0028] In Fig. Figure 2 schematically depicts patient P. One arm of patient P is equipped with an arterial access 20 and a venous access 21. An arterial tube 22 leads from the arterial access 20 to the blood pump 13. This pump pumps blood through a blood chamber 25a of a treatment device 25 in the form of a dialyzer 25, whose two chambers 25a and 25b are separated by a membrane 26. Chamber 25b is a dialysis fluid chamber through which dialysis fluid flows.

[0029] After leaving chamber 25a, the blood flows into a venous tube 23, which is connected to the venous port 21 or access port 21. In this way, a blood circulation is formed.

[0030] A pressure gauge 27 may measure the arterial blood pressure in the arterial line 22. Similarly, a pressure gauge 28 may measure the venous blood pressure in the venous line 23. Furthermore, the venous line 23 may interact directly or indirectly with a red detector 29, which detects the presence of blood in the tubing and reports this to the control unit 14. For example, the venous line 23 contains the detector 29. The pressure gauges 27 and 28, as well as the detector 29, are (if present) connected to the control unit 14. This unit controls the entire operation of the device 10 and monitors the functions described above, as well as a number of other functions that are not explained in detail here.

[0031] To isolate the blood circulation, a hose clamp 30, controlled by the control unit 14, is preferably provided in the venous line 23. A shut-off device, preferably in the form of a blood pump 13, can also be located in the arterial line 22. The blood pump 13 is a peristaltic pump that is continuously squeezed by a pinch valve. When the blood pump 13 stops, it acts as a shut-off device that closes the tubing.

[0032] The radar sensor 17 and its connection to the control unit 14 are in Fig. 2 recognizable.

[0033] A reference marker 35, detectable by the radar sensor 17, is preferably attached to the patient P's body, specifically to his chest. The radar sensor 17 is automatically adjusted by a (not shown) motion drive so that the reference marker 35 is located at a specific position in the radar image. This ensures that the radar sensor 17 is always directed at the desired target area, regardless of any movements of the patient P.

[0034] The control unit 14 in Fig. 2 is a computer with a storage unit. It performs all monitoring and control processes as well as alarm generation. The control unit 14 is connected to a display, operating and communication unit 15.

[0035] During dialysis, an extracorporeal blood flow of 50 to 600 ml / min is drawn from patient P using the blood pump. Blood is drawn from the arterial cannula 20 and subsequent line 22 by the peristaltic pump 13 and returned via the venous cannula 21 and subsequent line 23. The blood flows through lines 22 and 23, to which components such as the cannulas 20 and 21, the pressure sensors 27 and 28, and the dialyzer 25 are connected. Control and monitoring are performed by the control, processing, and storage unit 14. The parameters for patient P are entered via the display, operating, and communication unit 15. To interrupt the blood flow, the control unit 14 stops the blood pump 13 and closes the hose clamp 30. A visual and audible alarm is also triggered. This protects patient P from further harm, because no further blood loss can occur.

[0036] During therapy, the control / analysis unit 14 continuously compares the current respiratory rate (approx. 12-18 breaths / min) against preset upper and / or lower limits. For this purpose, at least one radar sensor 17 detects the movements of the reference marker 35 and sends corresponding signals to the control unit 14. The control unit determines breaths from the received signals and calculates the respiratory rate and / or the amplitude of the breaths. With a blood flow rate of 300 ml / min, the patient can lose 600 ml of blood within two minutes of the needle slipping out. This quickly leads to a state of shock with an increased respiratory rate and possibly shallower breaths. As soon as the analysis unit 14 detects, for example, an increased respiratory rate (> 20 breaths / min) for a defined period (e.g., 30 seconds), the blood pump is stopped and the alarm is triggered.

[0037] The alarm could also be triggered by a threshold window that the analysis unit 14 determines automatically after the blood flow starts and a waiting period. Around this initial value (e.g., 16 breaths / min), an upper and lower limit would then be defined (for example, upper limit = 20 breaths / min = initial value + 4 breaths / min and lower limit = 12 breaths / min = initial value - 4 breaths / min). Reference sign 10 Device 11 device bases 12 console 13 Blood pump 14 Control unit 15 card readers 16 IV poles 17 radar sensor 20 arterial access 21 venous access 22 arterial line 23 venous lines 25 Treatment device 25a,b Blood chamber 26 Membran 27 pressure gauges 28 pressure gauges 29 Blood Detector, Red Detector 30 Shut-off device, hose clamp 35 Reference marking Patient

Claims

Device (10) for extracorporeal blood treatment, in particular a dialysis device (10) comprising a radar sensor (17) for monitoring a patient (P) at a treatment station, at least one shut-off device (13, 30) for shutting off a line (23) connected venously to the patient (P) and / or for shutting off an arterial line (22) connected to the patient (P), in particular in the form of a hose clamp (30) clamping an elastic or flexible section of the line (22, 23), a blood pump, and a control unit (14), wherein the control unit (14) is configured and designed to determine a respiratory rate and / or respiratory amplitude of the patient (P) based on signals from the radar sensor (17) and to trigger an alarm signal if the respiratory rate and / or respiratory amplitude detected by the radar sensor (17) deviates from a preset limit value or several preset limit values, the shut-off device (13,30) in the event of an alarm, the control unit (14) can be activated automatically and the blood pump is stopped in the event of an alarm. Device (10) according to claim 1, characterized in that the radar sensor (17) is directly integrated into the device (10). Device (10) according to claim 1, characterized in that the radar sensor (17) is positionably arranged on the device (10), in particular by means of a linear guide (16) such as an IV pole (16). Device (10) according to one of the preceding claims, characterized in that the device (10) comprises a reference marker (35) that can be attached to the patient (P), in particular to his chest, for sensory interaction with the radar sensor (17). Device (10) according to one of the preceding claims, characterized in that the radar sensor (17) can be positioned by means of a drive, preferably automatically / self-positioning, for readjustment, in particular for automatic / self-adjustment, the alignment of the radar sensor (17) relative to the patient (P). Device (10) according to one of the preceding claims, characterized in that it has a red detector (29) for detecting the presence of blood in the piping system (22, 23) of the device (10).

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