Method and system for fluid balance monitoring for a patient

Abstract

The invention relates to a method and a system for automated fluid balance monitoring of a patient. The patient is in bed, at least intermittently, during a predetermined reference period. Each item used is marked with an identifier. A bed scale weighs the bed. A reading unit reads the identifiers on the items. A camera unit generates images, these images showing at least the bed and items near the bed. A signal processing unit determines a weight difference, that is, the difference between the weight of the bed at a first time point and its weight at a second time point. The signal processing unit calculates a fluid balance for the patient, which is the total amount of fluid supplied to the patient during the reference period minus the amount of fluid leaving the patient during the reference period.For this purpose, the signal processing unit uses the weight difference of which objects are being moved to or from the bed, as well as the respective amount of liquid that each moved object can hold.

Description

[0001] The invention relates to a method and a system for automated fluid balancing for a patient.

[0002] The invention is based on the object of providing a method and a system that can be used during the care of a patient who is at least temporarily confined to a bed. The method and the system are intended to reduce the risk of the patient suffering health damage.

[0003] The object is achieved by a method having the features of claim 1 and by a system having the features of claim 12. Advantageous embodiments are specified in the subclaims. Advantageous embodiments of the method according to the invention are, where appropriate, also advantageous embodiments of the system according to the invention, and vice versa.

[0004] The method and system according to the invention are capable of automatically performing a fluid balance for a patient and thereby providing a fluid balance for the patient. The method according to the invention is carried out using the system according to the invention.

[0005] A reference period is specified, for example, 24 hours in length. The fluid balance calculated according to the invention is the difference between the total amount of fluid supplied to the patient in the specified reference period and the amount of fluid removed from the patient in this reference period. The amount is preferably specified as a mass. The total fluid supplied to the patient in the reference period also includes the fluid that the patient actively consumes, for example by drinking from a drinking vessel. The total fluid removed from the patient in the reference period also includes the fluid that the patient sweats out or actively excretes outside of bed.

[0006] If the difference and thus the fluid balance are greater than zero, the patient has consumed fluid on balance during the reference period, otherwise the patient has lost fluid on balance.

[0007] The patient lies in a bed continuously or at least temporarily during the reference period. At least one movable object is used to care for the patient, or at least one movable object can be used. Movable means that the object can be moved during the care of the patient and relative to the patient. The object or at least one, preferably every object that is used or can be used, is provided with a machine-readable label. This label distinguishes the object from the object or every other object used, but at least from every different type of object. At least every object used or usable that can hold and provide a liquid is provided with a machine-readable label.

[0008] The identification of an object is stored, for example, in an NFC tag, where the NFC tag takes the form of an RFID tag. Alternatively, the identification takes the form of a barcode or QR code on the object. The identification can also include a sequence of alphanumeric characters and / or at least one symbol. The identification can also include multiple components. The identification can also include the contour and / or the color, or at least one color, of the object.

[0009] A computer-readable item list is specified. This item list is stored, for example, in a system data storage. It contains an entry for each used or usable marked item. The entry includes information about the machine-readable marking of the item as well as at least one of the following pieces of information: - information about the weight of the object, - information about the amount of liquid that this object can hold.

[0010] It is possible that the entry about an object with a marking includes the information that this object is not capable of absorbing liquid.

[0011] The system according to the invention comprises a reading unit with at least one reader and a camera unit with at least one camera. The or each reader has a reading range. The or each reader is capable of reading a machine-readable tag if the tag is within the reading range. The or each camera has a field of view. The bed is located within the respective reading range of each reader and within the respective field of view of each camera during the specified reference period. Preferably, neither the bed nor a reader nor a camera are moved during the reference period, in particular not relative to one another.

[0012] The or each camera is capable of generating at least one image, preferably a sequence of images. These images show the bed, optionally the patient in the bed, and optionally the or each object and person, provided that this object and person are in the camera's field of view. The camera is capable of generating a signal, which signal comprises the generated image or sequence of images. The or each reader is capable of reading the respective machine-readable marking of an object within the reading range of the reader and generating a signal comprising the reading result.

[0013] The system according to the invention also includes a bed scale. The bed scale is capable of measuring the current weight of the bed. If the patient is in bed at the time of measurement, the measured weight includes the weight of the bed, including the weight of any optional bedding, as well as the patient's weight. Based on the measured weight, it is possible to clearly determine whether the patient is in bed at the time of measurement or whether the bed is empty.

[0014] A signal processing unit of the system has at least temporary read access to the item list. The signal processing unit can be a component of a portable computer, such as a smartphone or tablet, or a component of a stationary computer, such as a PC.

[0015] The respective signal from each reader and camera is transmitted to the signal processing unit, preferably wirelessly via radio waves or alternatively via a data cable. The signal processing unit processes the received signals.

[0016] The method according to the invention comprises the following steps, and the system according to the invention is designed to carry out the following steps: The bed scale repeatedly measures the current weight of the bed during the reference period. The signal processing unit determines a first time point and a subsequent second time point, whereby the bed scale has measured the current weight of the bed at both times and the patient is lying in bed at both times. The first time point is preferably in the first third, particularly preferably in the first eighth, of the reference period, and the second time point is in the last third, particularly preferably in the last eighth. The bed scale preferably measures the current weight at least three times during the reference period, particularly preferably at a fixed sampling rate.

[0017] The signal processing unit derives at least one weight difference. The weight difference, or a weight difference, is the difference between the patient's weight at the second time point and the patient's weight at the first time point—more generally, the difference between the weight at a later time point and the weight at an earlier time point. This weight difference does not depend on the weight of the bed, because the bed scale weighs the weight of the bed at both the first and second time points, and the patient is in bed at both the first and second time points.

[0018] The reading unit reads the respective marking of an object within a reading range of a reading device. The camera unit generates at least one image, preferably a sequence of images, with the or each image showing at least the bed, as well as every movable object and every person who comes near the bed and thus into the field of view of a camera of the camera unit.

[0019] The signal processing unit detects every object that comes close to the patient and / or is removed from the patient during the reference period and therefore enters the reading range of at least one reader and / or the field of view of at least one camera. For this detection, the signal processing unit uses the signal(s) from a reader and the signal(s) from a camera.

[0020] It is possible for the signal processing unit to identify and detect an object based on both a signal from the reading unit and a signal from the camera. For example, the reading unit reads a machine-readable marking, and image processing identifies an optically detectable marking of the same object in a camera image.

[0021] The signal processing unit calculates a fluid balance for the patient. The term fluid balance has already been defined above. It refers to the specified reference period. To calculate the fluid balance, the signal processing unit uses - the derived weight difference, - information about which objects came near the bed during the reference period, - the information that and if so which objects were removed from the vicinity of the bed during the reference period and - the liquid quantities and / or weights of these items according to the item listing.

[0022] The signal processing unit determines which objects came near the bed and which objects were removed again based on a signal from the reading unit and / or a signal from the camera unit.

[0023] The item list includes, for each used or usable item and therefore also for each detected item, information about the empty weight of this item and / or the amount of liquid that this item can hold.

[0024] The method and system according to the invention can be applied to a patient, particularly while the patient is in a hospital, a care facility, or at home and while receiving medical care and / or nursing. The patient may suffer health damage if they do not consume enough fluid within the specified reference period. The fluid supplied should at least adequately replace the fluid excreted. If the fluid balance is negative and smaller than a specified lower limit, there is a risk that the patient will become dehydrated. Dehydration (exsiccosis) can lead to a disruption of the patient's water and electrolyte balance, thereby causing health damage to the patient.On the other hand, if the fluid balance is positive and greater than a given upper limit, there is a risk that fluid will settle in the patient's tissue and cause edema, which is also undesirable.

[0025] The patient's fluid balance during a given reference period is influenced by various factors. Because the system according to the invention comprises various sensors and the object list, and the method according to the invention processes signals from these sensors and the object list, many of these different influences can be quantitatively determined to calculate the fluid balance.

[0026] The invention can be used in conjunction with the step of weighing the patient out of bed, particularly immediately before the reference period and / or immediately after the reference period. It is possible to determine the difference between these two patient weights. However, the invention eliminates the need to weigh the patient out of bed. In routine clinical practice, the personnel and time for this are often lacking. Furthermore, the invention makes it possible to install and connect the components of the system according to the invention once for a single patient and then repeatedly calculate the fluid balance for different periods, even for different patients, without requiring human intervention. Furthermore, it is often not sufficient to provide a reliable fluid balance if the patient is simply weighed once before and once after the reference period.

[0027] According to the invention, a reading unit and a camera unit are used. This enables the signal processing unit to detect, in particular, which objects are brought near the bed and thus close to the patient in bed, and which objects are removed from the bed and thus from the patient. From the object list, the signal processing unit extracts the information regarding the amount of liquid each object can hold and is therefore delivered to the patient when the object comes close to the patient. It is often also possible to determine whether an object containing liquid is actually brought to the patient's mouth or not.Thanks to the object listing, the process of administering fluid to a patient can also be distinguished from a process in which an object is used near the patient without administering fluid to the patient, for example a piece of cutlery, a book or even a medical instrument, or a process in which a drinking vessel containing fluid is moved to the patient but the patient does not consume any fluid from this drinking vessel.

[0028] In one embodiment, the bed scale measures the current weight of the bed more than twice during the reference period, preferably at a predetermined sampling rate. The signal processing unit determines a temporal progression of the bed weight, for which it receives and processes a signal from the bed scale. The signal processing unit uses the temporal progression of the bed weight to calculate the fluid balance for the patient. The temporal progression refers at least to the time period between the first time and the second time, optionally to the entire reference period.

[0029] Thanks to this design, the signal processing unit can in many cases determine with greater certainty how much liquid the patient has consumed while lying in bed. By processing signals from the reading unit and the camera unit, the signal processing unit detects the event that an object is brought to the patient's body and later removed again, or establishes that such an event has not occurred. By evaluating the list of objects, the signal processing unit determines how much liquid this object is capable of absorbing and / or how much this object weighs without liquid. The temporal progression of the bed weight provides information on how the measured weight of the bed with the patient, and thus the patient's weight, has changed. This information is always available in relation to the respective times of measurement or detection.From this information, the signal processing unit determines how much fluid the patient has actually consumed. Thanks to the signals from the reading unit and the camera unit, this situation can be distinguished from a situation in which the patient grasps an object in bed, or an object is brought to or into the bed without the patient consuming any fluid.

[0030] In a further development of this embodiment, the signal processing unit automatically searches for a departure time, a subsequent return time, and a third time between these two times. The signal processing unit performs the search such that these three times cumulatively have the following properties: - All three points in time are within the specified reference period. - The current weight of the bed was measured at all three time points. - The patient was in bed both at the time of leaving and at the time of returning. - At the third time point, the patient was out of bed.

[0031] In particular, the signal processing unit uses the first time point as the exit time point and the second time point as the return time point.

[0032] As already mentioned, the signal processing unit uses a reading from the bed scale to determine whether the patient was in bed or out of bed at the time of the measurement. This is possible, but thanks to the bed scale, it's not necessary to use an additional sensor for this purpose.

[0033] If the signal processing unit has found three such points in time, it performs the following steps: - The signal processing unit calculates the difference between the measured weight of the bed at the time of leaving and the measured weight of the bed at the time of returning. - The signal processing unit uses the calculated difference to calculate the fluid balance.

[0034] At the third time point, i.e., in the period between the time of leaving the bed and the time of returning, the patient may have lost fluids outside of the bed, for example, by excreting them on a toilet, and may also have consumed fluids outside of the bed. The measured difference approximately indicates the balance between fluid loss and fluid intake in the period between the time of leaving the bed and the time of returning. This configuration can be combined with the process of weighing the patient at least once outside of the bed. However, thanks to this training, it is no longer necessary to weigh the patient outside of the bed during the period.

[0035] In one embodiment, the system comprises at least one volume flow sensor. The volume flow sensor is capable of measuring the volume flow of a liquid through a fluid guide unit, or alternatively or additionally, the mass flow of the liquid. More specifically, the volume flow sensor directly measures the volume flow or the mass flow, or a quantity that correlates with the volume flow and / or the mass flow.

[0036] According to the embodiment, the volume flow sensor measures the volume flow or mass flow of a liquid through a fluid guide unit while this fluid guide unit is connected to the patient's body. The liquid can flow through the fluid guide unit into the patient's body or flow out of the patient's body through the fluid guide unit. It is possible for a liquid to flow into the patient's body through one fluid guide unit and for the same or a different liquid to flow out of the patient's body and through a different fluid guide unit. For example, an infusion solution flows from a bag through the fluid guide unit into the patient's body, and urine flows out of the body and into a urine bag.The fluid flow unit is connected to the patient's body at least during the period between the first and second time points. The volume flow or mass flow is measured at least during this period.

[0037] In one implementation, a fluid guide unit is used such that fluid flows through the fluid guide unit in two opposite directions, one after the other. In this case, the volume flow sensor preferably also determines the current flow direction. The signal processing unit receives a signal from the volume flow sensor and uses the measured volume flow to calculate the fluid balance.

[0038] This embodiment further improves the accuracy and reliability with which the fluid balance is calculated according to the invention.

[0039] Notes: - A fluid guide unit is a component capable of guiding a fluid along a trajectory, where the trajectory is determined by the design and arrangement of the component. For example, the fluid guide unit comprises a tube and a hose. - Volume flow is the volume flowing through a fluid flow unit per unit of time. Mass flow is the mass flowing through the fluid flow unit per unit of time. The fluids that the patient ingests or dispenses during the reference period usually have a high water content and therefore a specific density approximately equal to the specific density of water. Therefore, the volume flow is approximately proportional to the mass flow.

[0040] In one embodiment, the system according to the invention comprises a urine bag scale. This urine bag is connected to the patient at least temporarily during the reference period. The patient releases urine into the urine bag via a tube, preferably via a catheter. The signal processing unit determines a temporal progression of the weight of the urine bag and processes a signal from the urine bag scale for this purpose. The temporal progression is measured at least in the period between the first time point and the second time point. The signal processing unit uses the temporal progression to calculate the fluid balance.

[0041] According to this embodiment, the signal processing unit processes a temporal progression of the weight of the urine bag. This allows the signal processing unit to determine the volume flow or mass flow into the urine bag. It also detects the event that the urine bag is replaced or emptied. This process typically results in a sudden change in the measured weight of the urine bag.

[0042] In one embodiment, the system according to the invention comprises a table scale. The table scale is capable of measuring the weight of a table. This table is located near the patient at least temporarily during the reference period. The table can stand on a floor or be connected to the bed. Objects that are used or can be used to care for the patient can be placed on this table. Some of these objects can contain liquid, for example drinks or solid food. The signal processing unit determines a temporal profile of the weight of the table and processes a signal from the table scale for this purpose. The temporal profile comprises at least the time period between the first time and the second time. The signal processing unit uses the determined temporal profile to calculate the fluid balance.

[0043] Thanks to this configuration, the signal processing unit is particularly capable of detecting the process of placing a container containing liquid on the table, gradually emptying it, and then removing it from the table. Preferably, the signal processing unit additionally detects this container using signals from the reading unit and / or the camera unit. By reading the item list, the signal processing unit determines the weight of this container and / or the amount of liquid it can hold. Combining different pieces of information increases the reliability with which the amount of liquid is calculated, with the patient consuming this amount of liquid from the container.

[0044] According to the invention, the reading unit comprises at least one reading device. The camera unit comprises at least one camera. In one embodiment, the reading unit comprises at least two reading devices, and / or the camera unit comprises at least two cameras. Preferably, the viewing directions of the reading devices differ from one another, and the viewing directions of the cameras also differ from one another. The signal processing unit determines the respective movement of each object relative to the bed during the reference period and additionally identifies this object based on the marking. In particular, the signal processing unit is thereby able to decide in many cases whether fluid is being delivered to the patient and / or fluid is being removed from the patient in this object and / or whether neither fluid is being delivered nor removed. The signal processing unit uses each determined relative movement to calculate the fluid balance.

[0045] Typically, the patient consumes liquid from a container at least once during the reference period. This container is designed to hold a drinkable liquid and be brought to the patient's mouth. For example, the container is placed on a support surface of a patient table, and the patient takes the container and drinks from it. Or the container is held in front of the patient's mouth. According to the invention, this container is also provided with a unique, machine-readable label. The weight of the container and / or the amount of liquid the container can hold is stored in the item list.

[0046] The following design allows the fluid balance to take into account, with relatively high reliability, the amount of fluid the patient consumes by drinking from a container during the reference period. The signal processing unit performs the following sequence at least once: - The signal processing unit detects the event that the container is brought to the patient's mouth. - It determines how long the patient drinks from this container. - It provides an approximate estimate of the amount of fluid the patient consumes from this container. - She uses this approximate value to calculate the fluid balance.

[0047] For this detection and for this determination, the signal processing unit uses at least one signal from the reading unit, at least one signal from the camera unit and the object list.

[0048] Thanks to the machine-readable identifiers and the camera unit, the movement of an object relative to the patient's bed can be easily tracked. Therefore, the signal processing unit can detect that a container-shaped object is brought to the patient's mouth. Furthermore, the signal processing unit can detect the event of liquid being spilled or that the patient brings the container to their mouth but does not drink.

[0049] The following design takes into account the possibility that the patient excretes fluid while lying in bed, and that this fluid is absorbed by textiles located in the bed, between the patient and the bed, or on the patient's body. Textiles include, in particular, a bed pad or the patient's clothing. For example, the patient sweats fluid. Because this fluid remains in the bed, it does not lead to a change in the weight measured by the bed scale or the optional table scale.

[0050] According to this embodiment, the signal processing unit is capable of detecting the event that the used item is replaced with a fresh item, for example, that the patient's bed linen and / or clothing is changed. For this detection, the signal processing unit uses a signal from the reading unit and / or a signal from the camera unit.

[0051] Before replacement, the object absorbed moisture that the patient had excreted in bed. Typically, the fresh object is of the same type as the replaced object, but fresh and therefore dry. The difference between the weight of the used object and the weight of the fresh object is therefore approximately equal to the weight of the fluid that the patient excreted in bed onto the used and then replaced object. It is possible to measure the weight of the used object before replacement and the weight of the fresh object. However, the following implementation avoids the need to measure the weight of this object separately.

[0052] According to this implementation, the weight of the bed is measured, on the one hand, before the replacement, i.e., at a time when the old object, which may have absorbed fluid, is still in the bed. On the other hand, the weight of the bed is measured after the replacement, i.e., at a time when the fresh object is in the bed, i.e., an object that has not yet absorbed a significant amount of fluid from the patient. Either the patient is in bed at both of these times. For example, the first time serves as the time before the replacement, the second time as the time after the replacement. Or the patient is out of bed at both of these times.As already explained, based on the weight measured by the bed scale at a given time, the signal processing unit can unambiguously determine whether the patient was in bed or out of bed at that time. The measured weight of the bed before the exchange minus the measured weight of the bed after the exchange provides an approximate weight of the fluid the patient expelled into the object before the exchange.

[0053] Another implementation does not necessarily require that the object that absorbs or can absorb fluid from the patient be replaced within the specified reference period and that this replacement be detected. According to this alternative implementation, the signal processing unit detects two points in time within the specified reference period, at both of which the current weight of the bed was measured and the patient was not in the bed. The signal processing unit calculates the difference between the bed weight at the later time and the bed weight at the earlier time. In many cases, this difference corresponds sufficiently accurately to the amount of fluid that the patient excreted into the bed between the earlier and later times.

[0054] The invention is described below using an exemplary embodiment. Fig. 1 schematically shows a patient in a patient bed, various items for patient care and the fluid balancing system according to the invention; Fig. 2 schematically the patient and the objects of Fig. 1 from a different perspective; Fig. 3 shows an example of which signals and other information the signal processing unit processes to calculate the fluid balance.

[0055] Fig. 1 and Fig. 2 schematically show a fluid balancing system 20 according to the invention. The same reference numerals have the same meanings. Application example

[0056] The fluid balancing system 20 is used to determine a fluid balance for a patient 10. The fluid balance refers to a predetermined reference period T and is the difference between the total amount of fluid supplied to the patient 10 during the reference period T and the total amount of fluid leaving the patient 10 during the reference period T. The reference period T has a length of 24 hours, for example.

[0057] During the reference period T, patient 10 lies continuously or at least temporarily in a bed, in this case in a patient bed 30 located in a room 12 of a hospital. During the reference period T, patient bed 30 remains in place. It is possible that patient 10 temporarily leaves patient bed 30. The bed can also be a normal bed or a couch and can be located in a room of an apartment or a care facility.

[0058] Patient 10 wears clothing 38 while lying in patient bed 30. Patient 10 is covered with bedding 34 or lies on bedding 34, where bedding 34 includes, for example, a duvet and a pillow. A bed base 36 is also located between patient 10 and patient bed 34.

[0059] Next to the patient bed 30 is a patient table 40 on which objects can be placed. The patient table 40 comprises a storage surface 40.1, an articulated support arm 40.2, and a base. Also next to the patient bed 30 is a mobile holding device 84 in the manner of a mobile coat rack, from which an infusion bag 82 hangs. During the reference period T, a tube 56 connects the infusion bag 82 to the body of the patient 10, continuously or at least temporarily. A liquid from the infusion bag 82 flows through the tube 56 into the body of the patient 10. A holding device 54 on the patient bed 50 holds a urine bag 50. A tube 58 connects the body of the patient 10 to the urine bag 50, continuously or at least temporarily. Components of the fluid balancing system

[0060] The fluid balancing system 20 of the embodiment includes - a bed scale 32, - a table scale 42, - a urine bag scale 52 and - a volume flow sensor 80.

[0061] The bed scale 32 is capable of measuring the weight Gew(30) of the patient bed 30. In the exemplary embodiment, the patient bed 30 rests on an external bed scale 32. When the patient 10 is lying in the patient bed 30, the bed scale 32 measures the sum of the weight of the patient bed 30 and the weight of the patient 10. When the patient 10 has left the patient bed 30, the bed scale 32 measures the weight of the empty patient bed 30 plus the weight of any bedding that remains in the patient bed 30.

[0062] The table scale 42 is capable of measuring the weight Gew(40) of the patient table 40. In the exemplary embodiment, the patient table 40 is positioned on the table scale 42. If at least one object is located on the support surface of the patient table 40, the table scale 42 additionally measures the weight of the or each object on the support surface.

[0063] The urine bag scale 52 is capable of measuring the weight Gew(50) of the urine bag 50. The volume flow sensor 80 measures the volume flow Vol'(56) or the mass flow from the infusion bag 82 through the tube 56. It is possible that fluid is being supplied to the body of the patient 10 from another container or device, or that fluid is being aspirated or otherwise removed, and the corresponding volume flow or mass flow is also being measured. The corresponding sensor can be a component of the device. The sensors 32, 42, 52, and 80 measure the respective physical quantity repeatedly, preferably at a fixed sampling frequency.

[0064] To care for the patient 10 while lying in the patient bed 30, several movable objects 60 are used. Examples of movable objects 60 shown are a drinking bottle 64, a cup 66, the bed linen 34, the bed pad 36, and the clothing 38 of the patient 10.

[0065] At least one, preferably every, object 60 is provided with a machine-readable marking 62, but at least every object that can absorb liquid. This marking 62 distinguishes this object 60 from every other, or at least from every different type of object used to care for the patient 10. Different examples of the same object 60 can therefore have the same marking 62. The marking 62 takes the form, for example, of an RFID tag, a barcode, a QR code, a specific pattern or symbol, or a sequence of alphanumeric characters. The color and / or contour of the object 60 can also be used alone or as a color-contour combination as the marking 62. The marking 62 is preferably applied multiple times to an object so that at least one marking 62 can be read.

[0066] The fluid balancing system 20 comprises a reading unit 72 with at least one reading device 74, preferably with multiple reading devices 74, and a camera unit 76 with at least one camera 78, preferably multiple cameras 78. The or each reading device 74 has a reading range. The or each camera 78 has a field of view Bf with a central viewing direction (viewing axis). Preferably, the fields of view of different cameras differ from one another, and at least two viewing directions are arranged obliquely or skewably relative to one another.

[0067] Preferably, each reader 74 and each camera 78 is fixedly mounted, for example, on a ceiling or a wall of the room 12 or on the patient table 40 or on the patient bed 30. The reader 74 and the camera 78 therefore maintain their position relative to the patient bed 30 during the reference period T. During the reference period T, the patient bed 30 is therefore continuously located in the or each reading area and in the or each field of view.

[0068] The or each reader 74 is capable of reading or otherwise detecting the respective marking 62 of each object within the reading range of the reader 74. Read(62) denotes a reading result of the reader 74. The reader 74 preferably repeatedly scans the markings 62 at a sampling frequency. The or each camera 78 is capable of recording an image Abb(60), preferably a sequence of images at a sampling frequency. Each reader 74 and each camera 78 each generate a signal with the respective reading result Read(62) or the respective image Abb(60) or the sequence of images. The image Abb(60) of a camera 78 thus shows - the patient bed 30, - the patient 10 when the patient 10 is in the patient bed 30, and - every person and every object 60 near the patient bed 30.

[0069] The fluid balancing system 20 further comprises a signal processing unit 22 with a data memory 24 and a processor 26. The processor 26 has at least temporary read access to the data memory 24 and executes a stored program. The signal processing unit 22 can be a component of a smartphone, tablet, or other portable computer. How the fluid balancing system works

[0070] The signals just described are transmitted to the signal processing unit 22, preferably wirelessly via electromagnetic radio waves 90. Fig. 3 shows an example of which signals and other information the signal processing unit 22 receives and processes. The signal processing unit 22 receives a signal from each reader 74 and each camera 78 and processes the received signals. By evaluating the signal from a reader 74, the signal processing unit 22 detects and identifies each machine-readable marking 62 within the reading range of the reader 74 and thereby detects and identifies the marked object 60. Optionally, the signal processing unit 22 determines how an object 60 with a specific marking 62 moves relative to the patient bed 30 based on a variable field strength of the signal from the reader 74. An image processing unit of the signal processing unit 22 processes the signal from a camera 78 and thereby detects each person and each object in the field of view of the camera 78.

[0071] In one embodiment, the image processing unit uses a classifier. This classifier detects and classifies objects in an image (60) from the camera 78. The classifier is preferably trained in advance with a sample, for which a machine learning method is applied. The classifier is implemented, for example, as a neural network. The implementation with the classifier creates redundancy and increases the reliability that a movement of an object 60 is correctly detected: An object 60 can be classified based on its marking 62, on the one hand, and on its contour, on the other.

[0072] Overall, the signal processing unit 22 uses the classification to determine the respective position and movement of each object 60 having a marking 62 relative to the patient bed 30 and thus relative to the patient 10. Furthermore, the signal processing unit 22 determines whether an object 60 has been at the mouth of the patient 10 for a sufficient length of time. If this object 60 is the drinking bottle 64 or the cup 66, this detection is a sign that the patient 10 is consuming liquid from this object 60 or is spilling liquid. This distinction cannot be reliably made solely by evaluating a signal from a scale.

[0073] In addition, the signal processing unit 22 receives a signal from the bed scale 32, the table scale 42, the urine bag scale 52 and the volume flow sensor 80, preferably also wirelessly via radio waves 90. In the exemplary embodiment, the signal processing unit 22 determines the following time profiles in the reference period T: - the time course of the weight of the patient bed 30, whereby if the patient 10 is lying in the patient bed 30, the measured weight includes the weight of the patient 10, otherwise only the measured weight of the patient bed 30 including the bed linen and the bed base, - the time course of the weight of the patient table 40, wherein, if at least one object 60 is on the patient table 40, the measured weight includes the weight of this object 60, - the time course of the weight of the urine bag 50 and - the time course of the volume flow through the hose 56.

[0074] Preferably, the signal processing unit 22 computationally compensates for short-term oscillations over time. Such oscillations are caused by short-term and small movements of the patient 10 or a caregiver, or even an external vibration source, and do not significantly affect the fluid balance. For example, the signal processing unit 22 applies a low-pass filter to the signal from each sensor 32, 42, 52, 80.

[0075] At least temporarily, the signal processing unit 22 has read access to a computer-analyzable object list 70. For example, the object list 70 is stored in the data memory 24. This object list 70 contains an entry for each object 60 that is detectable based on a marking 62 and / or by the optional classifier described above. This entry contains - information about the marking 62 and - information about the weight of the object 60 - and information about the mass and volume of liquid that this object can hold.

[0076] For example, in the case of a drinking vessel as object 60, the information includes information about the volume and / or the empty weight of the drinking vessel. It is, of course, possible that the object cannot hold liquid or is not used to hold liquid. If the object is a plate or bowl and can hold food, the listing includes information about the average amount of liquid contained in the consumed solid food. Calculation and evaluation of the fluid balance

[0077] The signal processing unit 22 calculates a fluid balance for the patient 10. In the exemplary embodiment, this fluid balance is the mass or volume of fluid that has been supplied to the patient 10 in total during the reference period T, minus the mass or volume of fluid that the patient 10 has removed in total during the reference period T.

[0078] The calculated fluid balance can be positive or negative. If the fluid balance is positive, patient 10 has, on balance, consumed more fluid in the reference period T than they have excreted. Otherwise, they have excreted more fluid than they have consumed. In one embodiment, a value range with an upper limit and, optionally, a lower limit is specified. The upper limit is greater than zero, the lower limit is less than zero. The fluid balance in the reference period T for patient 10 should lie within this value range. If the fluid balance is less than the lower limit, patient 10 has consumed too little fluid in the reference period T. In this case, there is a risk that patient 10 will become dehydrated. If the fluid balance is greater than the optional upper limit, there is a risk that fluid will be deposited in the tissue of patient 10, which is also undesirable.

[0079] Preferably, the signal processing unit 22 checks whether the fluid balance for the reference period T is within the value range or whether it is less than the lower limit or greater than the upper limit. If the fluid balance is outside the value range, the signal processing unit 22 generates a corresponding message and causes this message to be output in at least one form perceivable by a human, preferably by a receiver outside the room 12. Preferably, the message indicates whether the patient has consumed too much or too little fluid. In one embodiment, a corresponding message is also generated and output if the fluid balance is within the value range. A fluid balance far outside the value range can still be an indication that fluid intake or fluid intake was not detected or that a device of the system is malfunctioning.

[0080] Patient 10 consumes fluids in particular through the following actions: - A fluid is delivered to the patient 10 from the infusion bag 82 and through the tube 56. This delivery causes a volume flow and a mass flow through the tube 56, and the volume flow sensor 80 measures this volume flow or this mass flow. - A drinking vessel, for example the drinking bottle 64 and / or the cup 66 is placed on the patient table 40 - more precisely: on a support surface of the patient table 40. The patient 10 grasps the drinking vessel 64, 66, drinks from the drinking vessel 64, 66 and places the completely or at least partially emptied drinking vessel 64, 66 back on the patient table 40. The drinking vessel 64, 66 on the patient table 40 contributes to the measured weight of the patient table 40. The table scale 42 continuously measures the weight of the patient table 40. If the patient 10 holds the drinking vessel 64, 66 in one hand, the weight contributes to the weight measured by the bed scale 32.Preferably, the signal processing unit 22 compares the time course of the weight of the patient bed 30 with the time course of the weight of the patient table 40 in order to determine whether the patient 10 actually consumes liquid from a drinking vessel 64, 66 that was previously on the patient table 40. - A caregiver (not shown) holds the drinking vessel 64, 66 to the mouth of the patient 10, and the patient 10 drinks from the drinking vessel 64, 66 without placing the drinking vessel 64, 66 on the patient table 40. Drinking increases the weight of the patient bed 30.

[0081] In particular, the patient releases 10 fluids through the following actions: - Urine flows from the patient's 10 body through tube 58 into urine bag 50. The urine bag scale 52 measures the weight of urine bag 50, and the signal processing unit 22 determines a time-dependent change in the urine bag weight. If the measured weight suddenly decreases, the urine bag 50 has been replaced with a new, empty urine bag, and the signal processing unit 22 takes this into account. - Patient 10 leaves patient bed 30 and excretes fluid and / or stools on a toilet. Using a signal from bed scale 32, signal processing unit 22 determines the weight of patient 10 before leaving the patient bed and the weight after returning to patient bed 30. The weight difference approximately corresponds to the amount of fluid excreted. - The patient 10 releases fluid onto the clothing 38 or the bed pad 36, for example, because the patient 10 sweats fluid out. The amount of fluid released by the patient 10 in this way can be approximately determined when worn clothing 38 or a used bed pad 36 is replaced with fresh clothing 38 or a fresh bed pad 36. The difference between the weight of the used clothing / bed pad and the fresh clothing / bed pad approximately indicates the amount of fluid released. This difference is derived, for example, from the following difference: the weight of the patient bed 30 with the patient 10 before the exchange of items minus the weight of the patient bed 30 with the patient 10 after these items have been exchanged. In many cases, the image processing unit is capable of detecting the event that the clothing 38 and / or the bed pad 36 are exchanged.

[0082] The following events generally do not affect fluid balance: - Cutlery or a book or any other object that does not absorb liquid is placed on the patient table 40 or taken from the patient table 40.

[0083] Note: Because the signal processing unit 22 determines time courses and derives differences therefrom, the weight of the empty patient bed 30 or the weight of the empty patient table 40 is not necessarily required.

[0084] The exemplary embodiment takes into account the possibility that objects are placed on the patient table 40 and / or removed from the patient table 40 one after the other or simultaneously. Each object changes the weight of the patient table 40, and the table scale 42 weighs this weight. The weight of the object on the patient table 40 therefore influences the temporal progression of the weight of the patient table 40, with the signal processing unit 22 determining this temporal progression as described above. The signal processing unit 22 also uses the marking 62 to identify each object 60 that is placed on the patient table 40 or removed from the patient table 40, at least if this object 60 is capable of holding liquid. By reading the object list 70, the signal processing unit 22 determines how much liquid an identified object 60 is capable of holding.The signal processing unit 22 determines how much fluid the patient 10 has consumed from objects placed on the patient table 40 in total during the reference period T. To do so, the signal processing unit 22 uses the determined temporal progression of the weight of the patient table 40 and the amount of fluid that an identified object 60 on the patient table 40 can hold according to the object list 70. In particular, the signal processing unit 22 determines that an object, although it changes the weight of the patient table 40, does not absorb any fluid and therefore does not contribute to the fluid balance, for example, cutlery or a book. If an object 60 is not labeled, this object is preferably disregarded when calculating the fluid balance.In addition, the signal processing unit 22 optionally determines the event that the patient 10 spills liquid from an identified drinking vessel 60 and takes this into account approximately when calculating the liquid balance.

[0085] It is possible that a full drinking vessel, for example, the drinking bottle 64 or the cup 66, was placed on the patient table 40 before drinking and the empty drinking vessel is placed back on the patient table 40 after drinking. This changes the measured weight of the patient table 40. The possibility is taken into account that a nurse holds a drinking vessel 64, 66 in front of the patient's 10 mouth and the patient 10 drinks from the drinking vessel 64, 66 without the drinking vessel 64, 66 being placed on the patient table 40. In this case, the drinking vessel 64, 66 does not change the measured weight of the patient table 40.

[0086] The image processing unit of the signal processing unit 22 detects the event that a drinking vessel 64, 66 is brought to the mouth of the patient 10 and the event that the drinking vessel 64, 66 is moved away from the mouth of the patient 10. The signal processing unit 22 identifies the drinking vessel 64, 66 using the marking 62 and, through image analysis, determines that this drinking vessel 62 is located in front of the mouth of the patient 10. The signal processing unit 22 determines how much liquid this drinking vessel can hold by reading the object list 70. The signal processing unit 22 preferably uses the assumption that the patient 10 consumes this amount of liquid while the drinking vessel 64, 66 is held in front of his or her mouth.

[0087] In one embodiment, the possibility that liquid from a drinking vessel 64, 66 does not enter the body of the patient 10, but is poured out or spilled, is taken into account. The image analysis unit can also detect this event and approximately determine the amount of spilled liquid from a movement of the drinking vessel 64, 66. List of reference symbols 10 Patient, lying in the patient bed 30 12 hospital rooms in which the patient bed 30 with the patient 10 is located 20 Inventive fluid balancing system 22 Signal processing unit 24 Data memory of the signal processing unit 22 26 Processor of the signal processing unit 22 30 patient bed in which the patient lies 10 32 Bed scale, measures the weight Gew(30) of the patient bed 30 34 Bed linen in the patient bed 30, especially duvet and pillow 36 bed base 38 Clothing worn by the patient 10 in the patient bed 30 40 Patient table next to the patient bed 30, includes the storage area 40.1 and the holding arm 40.2 40.1 Patient table storage area 40 40.2 Articulated support arm of the patient table 40 42 Table scale, measures the weight Gew(40) of the patient table 40 50 urine bags, hanging on the holder 54 52 Urine bag scale, measures the weight Gew(50) of the urine bag 50 54 Holding device for the urine bag 50 at the patient bed 30 56 Tube connecting the patient's body 10 to the urine bag 50 58 Tube connecting the urine bag 50 to the patient's body 10 60 movable object used to care for patient 10 62 machine-readable marking of an object 60 64 Drinking bottle, is an item 60 66 cup, is an object 60 70 Item list, includes for each item 60 its marking 62 and the amount of liquid that this item 60 can hold, is stored in the data memory 24 72 Reading unit, includes at least one reading device 74 74 Reader, which is capable of reading a marking 62 on an object 60, is directed towards the patient bed 30, generates a reading result Read(62) 76 Camera unit, includes at least one camera 78 78 Camera, is directed at the patient bed 30, produces images Fig(60) 80 Volume flow sensor, measures the volume flow Vol'(56) or mass flow of a liquid flowing through the tube 56 82 Infusion bag, hanging on the holder 84, connected to the body of the patient 10 by the tube 56 84 Holding device for the infusion bag 82 90 radio waves Fig(60) Image of objects 60, generated by the camera 78 Bf field of view of the camera 78 Weight(30) Weight of patient bed 30, measured by bed scale 32 Gew(40) Weight of patient table 40, measured by table scale 42 Weight(50) Weight of urine bag 50, measured by the urine bag scale 52 Vol'(56) Volume flow with which liquid flows through the tube 56, measured by the volume flow sensor 80 Read(62) Reading result of reader 74

Claims

[1] Method for automated fluid balancing for a patient (10) using a system (20), where the system (20) - a bed scale (32), - a reading unit (72) with at least one reading device (74), - a camera unit (76) with at least one camera (78), - in computer-analyzable form a list of objects (70) and - a signal processing unit (22) includes, where for the care of the patient (10) - a bed (30) is used and - at least one movable object (60) is used or can be used, wherein the or at least one, preferably each used or usable object (60) is provided with a machine-readable marking (62) which distinguishes this object (60) from the or any other used object (60), where the item list (70) for each used item (60) - its marking (62) and - information about the weight and / or information about the amount of liquid that this object (60) is capable of holding, where a reference period for the fluid balance is specified, wherein the or each reading device (74) has a reading area and the bed (30) is located in this reading area at least during the reference period, wherein the or each camera (78) each has a field of view and the bed (30) is located in this field of view at least in the reference period, wherein the method is carried out at least in the reference period and comprises the steps of - the bed scale (32) measures the respective current weight [Gew(30)] of the bed (30) at least at a first time and at a subsequent second time, where both points in time are within the reference period and wherein the patient (10) is in bed (30) both at the first time and at the second time, - the signal processing unit (22) derives a weight difference using a signal from the bed scale (32), where the weight difference is the difference between the weight [Weight(30)] of the patient (10) at the second time point and the weight [Weight(30)] of the patient (10) at the first time point, - the reading unit (72) reads the respective marking (62) of at least one object (60), - the camera unit (76) generates at least one image [Fig(60)], preferably a sequence of images, - the signal processing unit (22) detects each object (60) that came into the vicinity of the patient (10) and / or was removed from the vicinity of the patient (10) during the reference period, wherein the step of detecting the or each object (60) is carried out using at least one signal [Read(62)] of the reading unit (72) and / or using at least one signal [Fig(60)] of the camera unit (76), and - the signal processing unit (22) calculates a fluid balance of the patient (10), wherein the fluid balance is the difference between the total amount of fluid supplied to the patient (10) during the reference period and the total amount of fluid leaving the patient (10) during the reference period, where for the calculation of the fluid balance - the or each derived weight difference of the bed (30), - the information about which objects (60) came close to the bed (30) and were detected, - the information as to which objects (60) were removed from the vicinity of the bed (30) and detected, and - the information on the weights and / or quantities of liquid included in the item list (70) for these items (60), be used. [2] Method according to claim 1, characterized by that the procedure includes the additional steps that - the bed scale (32) measures the current weight [Weight(30)] of the bed (30) at least once, preferably repeatedly, in the period between the first time and the second time, and - the signal processing unit (22) determines a time course of the weight [Weight(30)] of the bed (30) in this time period and uses the time course in the calculation of the fluid balance. [3] Method according to claim 1 or claim 2, characterized by , that the procedure includes the additional steps that the bed scale (32) measures the current weight [Weight(30)] of the bed (30) at a third time point between the first and second time points, the signal processing unit (22) checks whether the patient (10) is outside the bed (30) at the third time, and then, when the patient (10) is outside the bed (30) at the third time, the signal processing unit (22) - uses the first time point as a departure time point and the second time point as a subsequent return time point, - the difference between the measured weight of the bed (30) at the time of return and the measured weight of the bed (30) at the time of leaving as a difference between an amount of fluid that has been supplied to the patient (10) outside the bed (30) and an amount of fluid that has left the patient (10) outside the bed (30), and The determined weight difference is used to calculate the fluid balance. [4] Method according to one of the preceding claims, characterized by , that the system (20) comprises a volume flow sensor (80) and the procedure includes the additional steps that - the volume flow sensor (80) measures the volume flow or mass flow of a liquid through a fluid guide unit (56) into the body of the patient (10) and / or out of the body of the patient (10) and - the signal processing unit (22) uses the measured volume flow or mass flow in calculating the liquid balance, where the two additional steps - at least in the period between the first time and the second time and - when the patient's body (10) is connected to the fluid guide unit (56), be performed. [5] Method according to one of the preceding claims, characterized by , that the system (20) comprises a urine bag scale (52) and the procedure includes the additional steps that - the urine bag scale (52) repeatedly weighs the weight of a urine bag (50) in the period between the first time and the second time, the urine bag (50) being at least temporarily connected to the body of the patient (10) during this period, and - the signal processing unit (22) determines a time course of the measured weight of the urine bag (50) in the time period and uses the determined time course in the calculation of the fluid balance. [6] Method according to one of the preceding claims, characterized by , that the system (20) comprises a table scale (42) and the procedure includes the additional steps that - the table scale (42) repeatedly weighs the weight of a table (40) in the period between the first time and the second time, wherein objects which are used or can be used to care for the patient (10) are placed or can be placed on the table (40), and - the signal processing unit (22) determines a time course of the measured weight of the table (40) in this time period and uses the time course in the calculation of the liquid balance. [7] Method according to one of the preceding claims, characterized by , that the reading unit (72) comprises at least two readers (74) and / or the camera unit (76) comprises at least two cameras (78), wherein the step of the signal processing unit (22) detecting each object (60) comprises the steps of - the signal processing unit (22) determines the position and / or movement of the object (60) relative to the bed (30) at least once, preferably repeatedly, in the reference period, for which the signal processing unit (22) uses a signal from the or each reading device (74) and / or the or each camera (78), and - the signal processing unit (22) determines the temporal course of the position and / or the movement in the time period and uses it to calculate the fluid balance. [8] Method according to one of the preceding claims, characterized by , that at least one object (64, 66) used or usable for the care of the patient (10) is a container designed to hold a drinkable liquid and to be brought to the mouth of the patient (10), wherein the method comprises the further steps of the signal processing unit (22) - detecting the event that the container (64, 66) is brought to the mouth of the patient (10), - measures how long the patient (10) drinks from this container (64, 66), - determines an approximate value for the amount of liquid that the patient (10) consumes from this container (64, 66) and - uses this approximate value to calculate the fluid balance, wherein the signal processing unit (22) uses at least one signal from the reading unit (72) and / or at least one signal from the camera unit (76) as well as the object list for the detection and for the determination. [9] Method according to one of the preceding claims, characterized by , that an object (34, 36, 38) used to care for the patient (10) is designed to - to be arranged on or under the body of the patient (10) at least when the patient (10) is lying in bed (30), and - absorb fluid that the patient (10) excretes, wherein the method comprises the further steps of the signal processing unit (22) - the weight [Weight(30)] of the bed (30) at an earlier time and the weight [Weight(30)] of the bed (30) at a later time are determined, where both points in time are within the specified reference period, wherein the patient (10) is either in bed (30) at both times or outside the bed (30) at both times and wherein the weights are determined using a signal from the bed scale (32), and - calculate the difference between these two weights and - the calculated difference is used to calculate the fluid balance. [10] Method according to claim 9, characterized by that the method comprises the further steps that the signal processing unit (22) - detecting the event that the object (34, 36, 38) is exchanged on or under the body of the patient (10), for which the signal processing unit (22) uses a signal [Read(62)] of the or a reader (74) and / or a signal [Fig(60)] of the or a camera (78), and - the earlier point in time is used as a point in time before the exchange of the item and the later point in time is used as a point in time after the exchange. [11] Method according to claim 9 or claim 10, characterized by , that the object used is designed to remain in the bed (30) even when the patient (10) is not in the bed (30), and the signal processing unit (22) - a time at which the patient (10) is not in bed (30) is used as the earlier time and - another time point at which the patient (10) is also not in bed (30) is used as the later time point. [12] System (20) for automated fluid balance for a patient (10), wherein the system (20) is designed to be used in a situation in which for the care of the patient (10) - a bed (30) is used and - at least one movable object (60) is used or can be used, wherein the or at least one, preferably each used or usable object (60) is provided with a machine-readable marking (62) which distinguishes this object (60) from the or any other used object (60), where the system (20) - a bed scale (32), - a reading unit (72) with at least one reading device (74), - a camera unit (76) with at least one camera (78), - in computer-analyzable form a list of objects (70) and - a signal processing unit (22) includes, where the item list (70) for each used item (60) - its marking (62) and - information about the weight and / or information about the amount of liquid that this object (60) is capable of holding, where a reference period for the fluid balance is specified, wherein the or each reading device (74) has a reading area and the bed (30) is located in this reading area at least during the reference period, wherein the or each camera (78) has a field of view and the bed (30) is located in this field of view at least during the reference period, wherein the bed scale (32) is designed to measure the current weight [Weight(30)] of the bed (30) at least twice in the reference period, wherein the reading unit (72) is designed to read the respective marking (62) of an object (60), wherein the camera unit (76) is designed to generate at least one image [Fig(60)], preferably a sequence of images, wherein the signal processing unit (22) is designed to detect a first time and a second time, where both points in time are within the reference period, at both points in time the bed scale (32) measured the current weight of the bed and the patient (10) was in the bed (30) at both points in time, wherein the signal processing unit (22) is designed to derive a weight difference using a signal from the bed scale (32), where the weight difference is the difference between the weight [Weight(30)] of the patient (10) at the second time point and the weight [Weight(30)] of the patient (10) at the first time point, wherein the signal processing unit (22) is designed to detect any object (60) that comes into the vicinity of the patient (10) and / or is removed from the vicinity of the patient (10) in the period from the first time to the second time, wherein the signal processing unit (22) is designed to carry out this detection using at least one signal [Read(62)] of the reading unit (72) and using at least one signal [Fig(60)] of the camera unit (76), wherein the signal processing unit (22) is designed to calculate a fluid balance for the patient (10), and wherein the signal processing unit (22) is designed to calculate the fluid balance - the or each derived weight difference of the bed (30), - the information about which objects (60) have come near the bed (30), - the information as to which objects (60) have been removed from the vicinity of the bed (30), and - to use the information on the weights and / or quantities of liquid included in the item listing for these items (70). [13] System according to claim 12, characterized by , that the bed scale (32) is designed to measure the current weight [Weight(30)] of the bed (30) at a third time, where the third time point is between the first and the second time point, and the signal processing unit (22) is designed to check whether the patient (10) is outside the bed (30) at the third time, wherein the signal processing unit (22) is designed to, when the patient (10) is outside the bed (30) at the third time, to use the first time as a leaving time and the second time as a subsequent return time, the difference between the measured weight of the bed (30) at the return time and the measured weight of the bed (30) at the leaving time as a difference between an amount of fluid that has been supplied to the patient (10) outside the bed (30) and an amount of fluid that has left the patient (10) outside the bed (30), and to use the determined weight difference to calculate the fluid balance.

Images