WO2011026448A1 - A method and device for evaluation of the risk of decubitus development in a patient in a hospital bed - Google Patents

A method and device for evaluation of the risk of decubitus development in a patient in a hospital bed Download PDF

Info

Publication number
WO2011026448A1
WO2011026448A1 PCT/CZ2010/000093 CZ2010000093W WO2011026448A1 WO 2011026448 A1 WO2011026448 A1 WO 2011026448A1 CZ 2010000093 W CZ2010000093 W CZ 2010000093W WO 2011026448 A1 WO2011026448 A1 WO 2011026448A1
Authority
WO
WIPO (PCT)
Prior art keywords
patient
gravity centre
block
decubitus
risk
Prior art date
Application number
PCT/CZ2010/000093
Other languages
French (fr)
Inventor
Zbynek Frolik
Michal Jordan
Original Assignee
Linet Spol. S.R.O.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linet Spol. S.R.O. filed Critical Linet Spol. S.R.O.
Publication of WO2011026448A1 publication Critical patent/WO2011026448A1/en

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/1036—Measuring load distribution, e.g. podologic studies
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
    • A61B5/1118—Determining activity level
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/44—Detecting, measuring or recording for evaluating the integumentary system, e.g. skin, hair or nails
    • A61B5/441—Skin evaluation, e.g. for skin disorder diagnosis
    • A61B5/447—Skin evaluation, e.g. for skin disorder diagnosis specially adapted for aiding the prevention of ulcer or pressure sore development, i.e. before the ulcer or sore has developed
    • G—PHYSICS
    • G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H40/00—ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices
    • G16H40/60—ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices for the operation of medical equipment or devices
    • G16H40/63—ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices for the operation of medical equipment or devices for local operation
    • G—PHYSICS
    • G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H50/00—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics
    • G16H50/30—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics for calculating health indices; for individual health risk assessment

Definitions

  • the invention relates to a device for evaluation of the risk of decubitus formation in a patient in a hospital bed that comprises at least three force sensors that can be positioned under the loading area of the hospital bed and the outputs of the force sensors are connected to the input of the block for calculation of the position of the patient's gravity centre.
  • a number of devices are known that monitor the condition of patients that are confined to bed for a long time.
  • the weight of the patient is also monitored, namely by weighing directly on the bed.
  • An advantage is the possibility to track weight increases or decreases continually, without undesired handling of the patient.
  • the equipment for weighing in bed also provides other possibilities, e.g. remote monitoring whether the patient has left the bed, connection to a computer, locking the weighing device during handling of objects that do not need to be weighed, etc.
  • the sensors are installed in the undercarriage of the bed, i.e. the frame is the undercarriage frame and the weighed load is the patient including the loading area of the bed.
  • An advantage of this solution is a simpler design.
  • the main disadvantage is a higher measured weight, which moves during the lifting of the bed at the same time, as well as the fact that some accessories are also weighed.
  • the sensors are installed in the loading area, i.e. the frame is the undercarriage, incl. the lifting mechanism and the frame of the loading area and the weighed load is the patient with a support.
  • An advantage is a lower weight that is measured and the possibility to connect accessories to the bed in such a way that they are not weighed.
  • US patent no. 5276432 describes a system for detection of the patient's departure from the bed on the basis of evaluation of changes of the gravity centre position in the bed.
  • the detection mechanism is based on 4 tensometric sensors located in the corners of the bed frame. In a bed using this system it is possible to switch between three monitoring modes:
  • Patient position mode - the system checks whether values that are set in such a way to register small position changes have not been exceeded. This function is used to notify the personnel that the patient has moved, e.g. in case of waking up from a coma.
  • Bed leaving mode - the values are set in such a way to start an alarm in case the patient is about to leave the bed - e.g. when he/she is sitting at its edge.
  • Bed departure mode - if this mode is set, an alarm is only released if the patient leaves the bed completely. Only absolute decrease of weight on the bed surface is monitored.
  • a disadvantage of this system is the possibility of selecting only one mode at a time. This limitation mainly results from the capability of some communication systems in hospitals that only make it possible to transmit one alarm signal from a bed.
  • European patent application no. EP1974708 describes a system for prediction/detection of the patient leaving the bed.
  • the bed is equipped with 4 sensors in the corners of the supporting frame under the loading area. At given time intervals values of all the tensometers are read that are further digitally processed.
  • First, the gravity centre position is calculated.
  • the system contains several decision-making functions. The first one determines whether the weight is higher than the entered threshold value after the calculation of the gravity centre position in the Cartesian coordinate system and the other decision-making function determines whether it lies within the required limits.
  • Another function is used to set limit values depending on whether the backrest of the bed is lifted and depending on the current height of the loading area from the floor. So the system monitors whether the patient can reach the floor with his/her feet in a particular position. The system also monitors the absolute value of weight on the bed and starts an alarm if the minimum or maximum weight value is exceeded for a pre-defined time period. In principle, the same three zones can be monitored as in the case of the previous patent.
  • US patent application no. 20070268147 solves a system of monitoring a patient in a hospital bed with the use of 4 sensors.
  • the sensors are installed in the corners between the weighing frame and the undercarriage structure.
  • the threshold values do not define the limit position of the gravity centre, but standardized limit values for each sensor have been determined by measurement.
  • the values have been determined with regard to 78 places on the loading area from which the bed can be left.
  • These limit values are further adapted in accordance with the set sensitivity factor, current weight, lifting angle of the backrest or calfrest and the height of the bed.
  • the aim of the invention is to design a method and device that permanently monitors and evaluates the risk of decubitus development in a patient in a hospital bed without the presence of the nursing personnel.
  • the above mentioned aim is achieved with the use of a method of evaluation of the risk of decubitus development in a patient in a hospital bed comprising continuous monitoring of the position of the patient's gravity centre in accordance with the invention the principle of which is that the current position of the patient's gravity centre is compared to the previous position of the patient's gravity centre and if the established difference is higher than the preset limit value, this change of the gravity centre position is evaluated as a substantial movement while the dependence of the number of substantial movements of the patient on time is determined and if the number of substantial movements of the patient drops below the preset limit, the movement activity is evaluated as insufficient and information about the risk of decubitus development is issued.
  • An advantage of the method based on this invention is that the risk of decubitus development in a patient in a hospital bed can be predicted.
  • a change of the position of the patient's gravity centre is only evaluated as a new substantial movement if the change of the position of the patient's gravity centre occurs after the expiration of a longer time interval than the preset time interval.
  • a device for evaluation of the risk of decubitus development in a patient in a hospital bed that comprises at least three force sensors that can be installed under the loading area of a hospital bed and the outputs of the force sensors are connected to the input on the block for calculation of the position of the patient's gravity centre in accordance with the invention the principle of which is that the output of the block for calculation of the position of the patient's gravity centre is connected to the first input of the block for determination of the movement activity of the patient while the block for setting the boundary conditions is connected to the other input of the block for determination of the movement activity of the patient and the output of the block for determination of the patient's movement activity is connected to a display unit.
  • An advantage of the device in accordance with the invention is that without the presence of the nursing personnel it permanently monitors and evaluates the risk of decubitus development in a patient in a hospital bed.
  • the device for evaluation of the risk of decubitus development in a patient in a hospital bed is schematically represented in fig. 1.
  • the method of evaluation of the risk of decubitus development in a patient in a hospital bed is based on continuous monitoring of the position of the patient's gravity centre.
  • the established current position of the patient's gravity centre is compared to the previous value of the position of the patient's gravity centre.
  • the previous value of the gravity centre position may be e.g. the value established 1 sec ago or the average of previously established values.
  • the limit value defines the empirically defined difference between the original position of the patient's gravity centre and the new position of the patient's gravity centre that should be achieved so that this change of the position of the patient's gravity centre can be evaluated as a movement activity of the patient.
  • the established number of substantial movements of the patient is used to determine the dependence of substantial movements of the patient on time and if the number of substantial movements of the patient drops below the preset limit, information about the risk of decubitus development is issued.
  • the device for evaluation of the risk of decubitus development in a patient in a hospital bed in accordance with fig. 1 comprises four tensometric force sensors 3 located between the frame 2 and the loading area 1 of the hospital bed.
  • the outputs of the force sensors 3 are connected to the input of the block 4 for calculation of the position of the patient's gravity centre.
  • the position of the gravity centre is calculated with the use of any of the known methods. E.g. with the use of vector mathematics:
  • the vector for the direction of the given normal vector is calculated by multiplication of the normal vector by the proportion of the measured value of the particular force sensor 3 to the sum of the values of all the forces sensors 3: m
  • the established current position of the patient's gravity centre is compared to the previous value of the position of the patient's gravity centre. If the established difference between the current position of the gravity centre and the previous position of the gravity centre is higher than the preset limit value, this change of the gravity centre position is evaluated as a substantial movement of the patient.
  • the limit value defines the empirically defined difference between the original position of the patient's gravity centre and the new position of the patient's gravity centre that should be achieved so that this change of the position of the patient's gravity centre can be evaluated as a substantial movement of the patient.
  • the output of the block 4 for calculation of the position of the patient's gravity centre is connected to the first input of the block 5 for determination of the movement activity of the patient while the block 6 for setting the boundary conditions is connected to the other input of the block 5 for determination of the movement activity of the patient.
  • a boundary condition e.g. the signal of moving the bed side rails into the bottom position
  • the change of the position of the patient's gravity centre is not considered as a "substantial movement" of the patient as the movement of the bed side rails into the bottom position indicates that it is the nursing staff that handles the patient.
  • Another example of a boundary condition is the rest threshold. This threshold is used to get information whether the patient is at rest. This information is mainly important for setting the initial condition for the movement threshold.
  • This boundary condition mainly makes sense on simultaneous use of the boundary condition of the time threshold of rest. This value defines the time for which the patient must be at rest for the next movement to be registered. It is just this limitation that prevents registration of a number of movements following immediately after each other.
  • Another boundary condition will be the threshold of substantial movement. This value is used to find out whether the patient has performed a relevant movement with regard to the risk of decubitus development.
  • the value of the calculated differential vector is compared to this reference value, similarly to the rest threshold. The difference in this case is that it is not the vector difference of the current position of the gravity centre and the previous position of the gravity centre that is calculated, but the difference of the current position of the gravity centre and the reference position of the gravity centre.
  • the vector determining the reference position of the gravity centre may be referred to as This position is always set when the rest condition occurs for the first time.
  • the boundary conditions may either be set firmly by the manufacturer, or the user may get the possibility to adjust them.
  • the boundary conditions may also be adjusted automatically, e.g. depending on the patient's weight.
  • the information at the output of the block 5 for determination of the movement activity of the patient may have various forms. It can e.g. be displayed in the form of the curve of dependence of the size of the difference between the original position of the patient's gravity centre and the new position of the gravity centre on time, or in the form of numerical data defining the number of movement activities of the patient in the particular time interval, or the block 5 for determination of the movement activity of the patient may directly evaluate the risk rate of decubitus development.
  • reference values are used that can be entered via block 6 for setting the boundary conditions.
  • the information at the output of the block 5 for determination of movement activity of the patient may have the form of a simple message representing the risk rate of decubitus development. E.g.
  • the device for evaluation of the risk of decubitus development comprises of an A/D converter and a microprocessor while the display unit 7 comprises of a LCD screen.

Abstract

The method of evaluation of the risk of decubitus development in a patient in a hospital bed comprises continuous monitoring of the position of the patient's gravity centre. The current position of the patient's gravity centre is compared to the previous position of the patient's gravity centre and if the established difference is higher than the preset limit value, this change of the gravity centre position is evaluated as a substantial movement while the dependence of the number of substantial movements of the patient on time is determined and if the number of substantial movements of the patient drops below the preset limit, the movement activity is evaluated as insufficient and information about the risk of decubitus development is issued. The device for evaluation of the risk of decubitus development in a patient in a hospital bed comprises at least three force sensors (3) that can be installed under the loading area (1) of a hospital bed and the outputs of the force sensors (3) are connected to the input on the block (4) for calculation of the position of the patient's gravity centre. The output of the block (4) for calculation of the position of the patient's gravity centre is connected to the first input of the block (5) for determination of the movement activity of the patient. The block (6) for setting the boundary conditions is connected to the other input of the block (5) for determination of the movement activity of the patient. The output of the block (5) for determination of the patient's movement activity is connected to a display unit (7).

Description

A method and device for evaluation of the risk of decubitus development in a patient in a hospital bed
Technical Field
The invention relates to a device for evaluation of the risk of decubitus formation in a patient in a hospital bed that comprises at least three force sensors that can be positioned under the loading area of the hospital bed and the outputs of the force sensors are connected to the input of the block for calculation of the position of the patient's gravity centre.
Background Art
A number of devices are known that monitor the condition of patients that are confined to bed for a long time.
Besides monitoring of the basic vital functions the weight of the patient is also monitored, namely by weighing directly on the bed. An advantage is the possibility to track weight increases or decreases continually, without undesired handling of the patient. The equipment for weighing in bed also provides other possibilities, e.g. remote monitoring whether the patient has left the bed, connection to a computer, locking the weighing device during handling of objects that do not need to be weighed, etc.
In existing beds two types of configuration of the bed with a weighing device are principally used.
In the first type the sensors are installed in the undercarriage of the bed, i.e. the frame is the undercarriage frame and the weighed load is the patient including the loading area of the bed. An advantage of this solution is a simpler design. The main disadvantage is a higher measured weight, which moves during the lifting of the bed at the same time, as well as the fact that some accessories are also weighed. In the other type the sensors are installed in the loading area, i.e. the frame is the undercarriage, incl. the lifting mechanism and the frame of the loading area and the weighed load is the patient with a support. An advantage is a lower weight that is measured and the possibility to connect accessories to the bed in such a way that they are not weighed.
US patent no. 5276432 describes a system for detection of the patient's departure from the bed on the basis of evaluation of changes of the gravity centre position in the bed. The detection mechanism is based on 4 tensometric sensors located in the corners of the bed frame. In a bed using this system it is possible to switch between three monitoring modes:
1. Patient position mode - the system checks whether values that are set in such a way to register small position changes have not been exceeded. This function is used to notify the personnel that the patient has moved, e.g. in case of waking up from a coma.
2. Bed leaving mode - the values are set in such a way to start an alarm in case the patient is about to leave the bed - e.g. when he/she is sitting at its edge.
3. Bed departure mode - if this mode is set, an alarm is only released if the patient leaves the bed completely. Only absolute decrease of weight on the bed surface is monitored.
A disadvantage of this system is the possibility of selecting only one mode at a time. This limitation mainly results from the capability of some communication systems in hospitals that only make it possible to transmit one alarm signal from a bed.
European patent application no. EP1974708 describes a system for prediction/detection of the patient leaving the bed. The bed is equipped with 4 sensors in the corners of the supporting frame under the loading area. At given time intervals values of all the tensometers are read that are further digitally processed. First, the gravity centre position is calculated. The system contains several decision-making functions. The first one determines whether the weight is higher than the entered threshold value after the calculation of the gravity centre position in the Cartesian coordinate system and the other decision-making function determines whether it lies within the required limits.
Another function is used to set limit values depending on whether the backrest of the bed is lifted and depending on the current height of the loading area from the floor. So the system monitors whether the patient can reach the floor with his/her feet in a particular position. The system also monitors the absolute value of weight on the bed and starts an alarm if the minimum or maximum weight value is exceeded for a pre-defined time period. In principle, the same three zones can be monitored as in the case of the previous patent.
The published international application WO/2008/065402 describes a patient monitoring system that is based on force sensors under the loading area of the bed again. However, its main difference consists in the fact that it can only use one that monitors the load and compares it to the limit value set by the user. If it is exceeded, an alarm is released. To avoid accidental activation of this alarm a time interval may also be set for which the value must be outside the limits for the alarm to be issued.
US patent application no. 20070268147 solves a system of monitoring a patient in a hospital bed with the use of 4 sensors. The sensors are installed in the corners between the weighing frame and the undercarriage structure. In this case the threshold values do not define the limit position of the gravity centre, but standardized limit values for each sensor have been determined by measurement. The values have been determined with regard to 78 places on the loading area from which the bed can be left. These limit values are further adapted in accordance with the set sensitivity factor, current weight, lifting angle of the backrest or calfrest and the height of the bed. With this device you can also set monitoring of three basic conditions as well. The first one reports that the patient has moved, the second one that he/she is going to leave the bed and the third one that he/she has left the bed already.
All the described known systems with force sensors make it possible to monitor whether the patient has moved on the bed or even left the bed.
However, in patients that are confined to bed for a long time there is also a danger that they develop decubitus (bedsore). This danger is considerably lower in patients whose health condition allows them to change their position at least to a minimal extent. Therefore, for the nursing personnel it is desirable to be constantly informed about the "movement activity" of the patient in bed. The term "movement activity" of the patient in this case does not mean any arbitrary movement, but only such a frequency of substantial movements of the patient in bed that minimizes the danger of decubitus development. On the basis of long-term observations we know under what limit the patient's "movement activity" must not decrease so that the danger of decubitus formation should not significantly increase.
So the aim of the invention is to design a method and device that permanently monitors and evaluates the risk of decubitus development in a patient in a hospital bed without the presence of the nursing personnel.
Disclosure of Invention
The above mentioned aim is achieved with the use of a method of evaluation of the risk of decubitus development in a patient in a hospital bed comprising continuous monitoring of the position of the patient's gravity centre in accordance with the invention the principle of which is that the current position of the patient's gravity centre is compared to the previous position of the patient's gravity centre and if the established difference is higher than the preset limit value, this change of the gravity centre position is evaluated as a substantial movement while the dependence of the number of substantial movements of the patient on time is determined and if the number of substantial movements of the patient drops below the preset limit, the movement activity is evaluated as insufficient and information about the risk of decubitus development is issued.
An advantage of the method based on this invention is that the risk of decubitus development in a patient in a hospital bed can be predicted.
In a preferred embodiment a change of the position of the patient's gravity centre is only evaluated as a new substantial movement if the change of the position of the patient's gravity centre occurs after the expiration of a longer time interval than the preset time interval.
The above mentioned aim is also achieved with a device for evaluation of the risk of decubitus development in a patient in a hospital bed that comprises at least three force sensors that can be installed under the loading area of a hospital bed and the outputs of the force sensors are connected to the input on the block for calculation of the position of the patient's gravity centre in accordance with the invention the principle of which is that the output of the block for calculation of the position of the patient's gravity centre is connected to the first input of the block for determination of the movement activity of the patient while the block for setting the boundary conditions is connected to the other input of the block for determination of the movement activity of the patient and the output of the block for determination of the patient's movement activity is connected to a display unit.
An advantage of the device in accordance with the invention is that without the presence of the nursing personnel it permanently monitors and evaluates the risk of decubitus development in a patient in a hospital bed.
Brief Description of Drawings
The device for evaluation of the risk of decubitus development in a patient in a hospital bed is schematically represented in fig. 1.
Modes for Carrying Out the Invention The method of evaluation of the risk of decubitus development in a patient in a hospital bed is based on continuous monitoring of the position of the patient's gravity centre. The established current position of the patient's gravity centre is compared to the previous value of the position of the patient's gravity centre. The previous value of the gravity centre position may be e.g. the value established 1 sec ago or the average of previously established values.
If the difference between the current position of the gravity centre and the previous position of the gravity centre is higher than the preset limit value, this change of the position of the patient's gravity centre is evaluated as a substantial movement of the patient.
The limit value defines the empirically defined difference between the original position of the patient's gravity centre and the new position of the patient's gravity centre that should be achieved so that this change of the position of the patient's gravity centre can be evaluated as a movement activity of the patient.
One should realize that not every change of the position of the patient's gravity centre is decisive for evaluation of the risk of decubitus development in a patient that is confined to a hospital bed for a long time. E.g. if a monitored patient moves in the bed five times for one minute in the course of one hour, the risk of decubitus development is substantially lower than if a patient only moves once for five minutes in the course of an hour in spite of the fact that in both the cases the movement of the gravity centre for 5 minutes in the course of an hour was recorded.
The established number of substantial movements of the patient is used to determine the dependence of substantial movements of the patient on time and if the number of substantial movements of the patient drops below the preset limit, information about the risk of decubitus development is issued. The device for evaluation of the risk of decubitus development in a patient in a hospital bed in accordance with fig. 1 comprises four tensometric force sensors 3 located between the frame 2 and the loading area 1 of the hospital bed.
The outputs of the force sensors 3 are connected to the input of the block 4 for calculation of the position of the patient's gravity centre.
In the block 4 for calculation of the position of the patient's gravity centre the position of the gravity centre is calculated with the use of any of the known methods. E.g. with the use of vector mathematics:
From the i' m2> m¾ m signals of the force sensors 3 the sum of signals is obtained
m -∑mn
Then, individual wi »'¾ » '¾ » ', normal vectors are determined for the directions to the mounting positions of individual force sensors 3 from the geometrical centre of the square formed by these force sensors 3.
This means that their values express the coordinates of the fixing points of the tensometric force sensors 3:
»I = (';T)
«J = (-'';- ')
«4 = )
The vector for the direction of the given normal vector is calculated by multiplication of the normal vector by the proportion of the measured value of the particular force sensor 3 to the sum of the values of all the forces sensors 3: m
d - »„— - m
The position of the patient's gravity centre is calculated as the sum of all these vectors: e = {a3 +bx ±cx +dx;af +by +ev +df)
The established current position of the patient's gravity centre is compared to the previous value of the position of the patient's gravity centre. If the established difference between the current position of the gravity centre and the previous position of the gravity centre is higher than the preset limit value, this change of the gravity centre position is evaluated as a substantial movement of the patient.
The limit value defines the empirically defined difference between the original position of the patient's gravity centre and the new position of the patient's gravity centre that should be achieved so that this change of the position of the patient's gravity centre can be evaluated as a substantial movement of the patient.
As described above, not every change of the position of the patient's gravity centre is decisive for evaluation of the risk of decubitus development in a patient confined to a hospital bed for a long time.
Therefore, the output of the block 4 for calculation of the position of the patient's gravity centre is connected to the first input of the block 5 for determination of the movement activity of the patient while the block 6 for setting the boundary conditions is connected to the other input of the block 5 for determination of the movement activity of the patient.
It is just the introduction of boundary conditions in block 5 for determination of the patient's movement activity that ensures that as the patient's movement activity only such changes of the gravity point position are registered that have a positive impact on prevention of decubitus development.
As an example of a boundary condition e.g. the signal of moving the bed side rails into the bottom position can be mentioned. In such a case the change of the position of the patient's gravity centre is not considered as a "substantial movement" of the patient as the movement of the bed side rails into the bottom position indicates that it is the nursing staff that handles the patient.
Another example of a boundary condition is the rest threshold. This threshold is used to get information whether the patient is at rest. This information is mainly important for setting the initial condition for the movement threshold.
The calculation of the change size is based on the presumption that samples are taken after one second and that the previous position of the gravity centre is available in vector expression as *<au> (*au »·>¾--«>) . Then, the new position of the gravity centre is expressed with the ^*'-^ vector. So their differential vector ^ can be easily calculated as:
r = J(x- xfllJ>y + {y -y0w?
This is exactly the way of expressing the movement change that occurred in the time interval of one second. It is just the size of the ' vector that is compared to the set limit value for determination of rest.
This boundary condition mainly makes sense on simultaneous use of the boundary condition of the time threshold of rest. This value defines the time for which the patient must be at rest for the next movement to be registered. It is just this limitation that prevents registration of a number of movements following immediately after each other.
Another boundary condition will be the threshold of substantial movement. This value is used to find out whether the patient has performed a relevant movement with regard to the risk of decubitus development. The value of the calculated differential vector is compared to this reference value, similarly to the rest threshold. The difference in this case is that it is not the vector difference of the current position of the gravity centre and the previous position of the gravity centre that is calculated, but the difference of the current position of the gravity centre and the reference position of the gravity centre. The vector determining the reference position of the gravity centre may be referred to as This position is always set when the rest condition occurs for the first time.
The boundary conditions may either be set firmly by the manufacturer, or the user may get the possibility to adjust them. The boundary conditions may also be adjusted automatically, e.g. depending on the patient's weight.
The information at the output of the block 5 for determination of the movement activity of the patient may have various forms. It can e.g. be displayed in the form of the curve of dependence of the size of the difference between the original position of the patient's gravity centre and the new position of the gravity centre on time, or in the form of numerical data defining the number of movement activities of the patient in the particular time interval, or the block 5 for determination of the movement activity of the patient may directly evaluate the risk rate of decubitus development. For this purpose reference values are used that can be entered via block 6 for setting the boundary conditions. In such a case the information at the output of the block 5 for determination of movement activity of the patient may have the form of a simple message representing the risk rate of decubitus development. E.g. "LOW", "MEDIUM", "HIGH" risk may be represented by the "GREEN", "ORANGE", "RED" signals. Depending on the form of information at the output of the block 5 for determination of movement activity of the patient the type of the display unit 7 is selected.
In the described embodiment the device for evaluation of the risk of decubitus development comprises of an A/D converter and a microprocessor while the display unit 7 comprises of a LCD screen.

Claims

1. A method of evaluation of the risk of decubitus development in a patient in a hospital bed comprising continuous monitoring of the position of the patient's gravity centre, characterised in that the current position of the patient's gravity centre is compared to the previous position of the patient's gravity centre and if the established difference is higher than the preset limit value, this change of the gravity centre position is evaluated as a substantial movement while the dependence of the number of substantial movements of the patient on time is determined and if the number of substantial movements of the patient drops below the preset limit, the movement activity is evaluated as insufficient and information about the risk of decubitus development is issued.
2. The method of evaluation of the risk of decubitus development according to claim 1 , characterised in that a change of the position of the patient's gravity centre is only evaluated as a new substantial movement if the change of the position of the patient's gravity centre occurs after the expiration of a longer time interval than the preset time interval.
3. A device for evaluation of the risk of decubitus development in a patient in a hospital bed that comprises at least three force sensors (3) that can be installed under the loading area (1) of a hospital bed and the outputs of the force sensors (3) are connected to the input on the block (4) for calculation of the position of the patient's gravity centre, characterised in that the output of the block (4) for calculation of the position of the patient's gravity centre is connected to the first input of the block (5) for determination of the movement activity of the patient while the block (6) for setting the boundary conditions is connected to the other input of the block (5) for determination of the movement activity of the patient and the output of the block (5) for determination of the patient's movement activity is connected to a display unit (7).
PCT/CZ2010/000093 2009-09-02 2010-08-16 A method and device for evaluation of the risk of decubitus development in a patient in a hospital bed WO2011026448A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CZPV2009-585 2009-09-02
CZ2009585 2009-09-02

Publications (1)

Publication Number Publication Date
WO2011026448A1 true WO2011026448A1 (en) 2011-03-10

Family

ID=43430615

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CZ2010/000093 WO2011026448A1 (en) 2009-09-02 2010-08-16 A method and device for evaluation of the risk of decubitus development in a patient in a hospital bed

Country Status (1)

Country Link
WO (1) WO2011026448A1 (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5276432A (en) 1992-01-15 1994-01-04 Stryker Corporation Patient exit detection mechanism for hospital bed
EP0853918A2 (en) * 1996-12-24 1998-07-22 Pegasus Airwave Limited Patient movement detection
US20070268147A1 (en) 2004-08-09 2007-11-22 Hill-Rom Services, Inc. Load-cell based hospital bed control
US7378975B1 (en) * 2000-06-09 2008-05-27 Bed-Check Corporation Method and apparatus for mitigating the risk of pressure sores
WO2008065402A1 (en) 2006-11-29 2008-06-05 Huntleigh Technology Limited Patient monitoring system
JP2008206867A (en) * 2007-02-27 2008-09-11 Paramount Bed Co Ltd Rolling-over promotion apparatus
EP1974708A1 (en) 2006-01-20 2008-10-01 Paramount Bed Company Limited Bed apparatus with off-bed prediction/detection system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5276432A (en) 1992-01-15 1994-01-04 Stryker Corporation Patient exit detection mechanism for hospital bed
EP0853918A2 (en) * 1996-12-24 1998-07-22 Pegasus Airwave Limited Patient movement detection
US7378975B1 (en) * 2000-06-09 2008-05-27 Bed-Check Corporation Method and apparatus for mitigating the risk of pressure sores
US20070268147A1 (en) 2004-08-09 2007-11-22 Hill-Rom Services, Inc. Load-cell based hospital bed control
EP1974708A1 (en) 2006-01-20 2008-10-01 Paramount Bed Company Limited Bed apparatus with off-bed prediction/detection system
WO2008065402A1 (en) 2006-11-29 2008-06-05 Huntleigh Technology Limited Patient monitoring system
JP2008206867A (en) * 2007-02-27 2008-09-11 Paramount Bed Co Ltd Rolling-over promotion apparatus

Similar Documents

Publication Publication Date Title
US20210298682A1 (en) Patient support apparatus with patient information sensors
AU2007327114B2 (en) Patient monitoring system
JP5086996B2 (en) Bed presence detection method
KR101043864B1 (en) Bed apparatus with off-bed prediction/detection system
US8838411B2 (en) Bed device
EP2371336A2 (en) Presence detector and occupant support employing the same
JP3093745B2 (en) Sleeper equipment
US11213444B2 (en) On-bed state monitoring system
EP3801251B1 (en) Assembly, configured to detect a body on a support
WO2011026448A1 (en) A method and device for evaluation of the risk of decubitus development in a patient in a hospital bed
JP4832891B2 (en) Bed presence detection method
JP5204263B2 (en) Bed presence detection method and bed presence detection device
US20210068710A1 (en) System and process for monitoring a position stability
JP2019051097A (en) Stay-in-bed state watching system
US20230190205A1 (en) Mobility level user interface including smart turn reminders based on risk of patient
JP2006305343A (en) Bed occupancy state detection method
JP5406334B2 (en) Bed presence detection method and bed presence detection device
KR20210087608A (en) A fall prevention bed
JP2012161681A (en) Bed occupancy state detection method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10772952

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10772952

Country of ref document: EP

Kind code of ref document: A1