Key information

Title
APPARATUS FOR ESTABLISHING ABSENCE OF PAIN IN A MAMMAL
Application number
20191365
Case type
National
Status
17.01.2022 Patent meddelt (B1)
Filed
18.11.2019
Effective date
18.11.2019
Publicly available
19.05.2021
Next annual fee due
30.11.2027
Applicant
Med Storm Innovation AS (NO)
Owner
Med Storm Innovation AS (NO)
Inventor
Hanne Storm (NO)
Agent
ACAPO ONSAGERS AS (NO)
Granted
17.01.2022
Patent number
346051
Expiry date
18.11.2039

Abstract and drawing

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content.
A method and an apparatus for establishing absence of pain in a human or other mammal have been disclosed. The method comprises the steps of providing a skin conductance signal measured at an area of the mammal's skin through a time interval; detecting peaks in the skin conductance signal through said time interval; determining a rate of the peaks through the time interval; comparing the determined rate of peaks with a predetermined reference value; and if the measured rate of peaks is lower than the predetermined reference value, providing an output signal as indicating the state of absence of pain in the mammal.

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 Date Doc. No. Process Case number In/Out Journal description To/from
 27.01.2022 18-01 Saksbehandling 20191365 UT Generelt brev uten frist ENG ONSAGERS AS
 21.01.2022 17-02 Saksbehandling 20191365(346051) INN Letter to NIPO - correction of Letters Patent ONSAGERS AS
 21.01.2022 17-01 Saksbehandling 20191365(346051) INN Korrespondanse (Hovedbrev inn) ONSAGERS AS
 19.01.2022 16-01 Saksbehandling 20191365(346051) UT PT Registreringsbrev Nasjonal Patent (15) (PT20191365)
08.12.2021 15-01 Saksbehandling 20191365 UT Intention to grant ONSAGERS AS
 27.08.2021 14-05 Saksbehandling 20191365 INN P27108NO00 Specification_publication_markup ONSAGERS AS
 27.08.2021 14-04 Saksbehandling 20191365 INN P27108NO00 Specification_publication_CC ONSAGERS AS
 27.08.2021 14-03 Saksbehandling 20191365 INN P27108NO00 Response to Office Action ONSAGERS AS
 27.08.2021 14-02 Saksbehandling 20191365 INN P27108NO00 Claims in Norwegian ONSAGERS AS
 27.08.2021 14-01 Saksbehandling 20191365 INN Korrespondanse (Hovedbrev inn) ONSAGERS AS
 25.06.2021 13-01 Saksbehandling 20191365 UT Substantive examination ONSAGERS AS
 12.03.2021 12-08 Saksbehandling 20191365 INN L7 Scavone ONSAGERS AS
 12.03.2021 12-07 Saksbehandling 20191365 INN L6 Bini ONSAGERS AS
 12.03.2021 12-06 Saksbehandling 20191365 INN L5 Moscovitch ONSAGERS AS
 12.03.2021 12-05 Saksbehandling 20191365 INN L4 Khalfa ONSAGERS AS
 12.03.2021 12-04 Saksbehandling 20191365 INN L3 Gao ONSAGERS AS
 12.03.2021 12-03 Saksbehandling 20191365 INN L2 Latham ONSAGERS AS
 12.03.2021 12-02 Saksbehandling 20191365 INN L1 Romano ONSAGERS AS
 12.03.2021 12-01 Saksbehandling 20191365 INN Korrespondanse (Hovedbrev inn) ONSAGERS AS
 12.03.2021 11-04 Saksbehandling 20191365 INN P27108NO00 Letter_to_NIPO ONSAGERS AS
 12.03.2021 11-03 Saksbehandling 20191365 INN P27108NO00 Amended claims ONSAGERS AS
 12.03.2021 11-02 Saksbehandling 20191365 INN P27108NO00 Amended claims. markup version ONSAGERS AS
 12.03.2021 11-01 Saksbehandling 20191365 INN Korrespondanse (Hovedbrev inn) ONSAGERS AS
 22.01.2021 10-02 Saksbehandling 20191365 INN P27108NO00 Term extension request Jan 22, 2021 ONSAGERS AS
 22.01.2021 10-01 Saksbehandling 20191365 INN Korrespondanse (Hovedbrev inn) ONSAGERS AS
 26.10.2020 09-02 Saksbehandling 20191365 INN P27108NO00 Copies request Oct 26, 2020 ONSAGERS AS
 26.10.2020 09-01 Saksbehandling 20191365 INN Korrespondanse (Hovedbrev inn) ONSAGERS AS
 23.10.2020 08-01 Saksbehandling 20191365 UT Substantive examination ONSAGERS AS
 01.07.2020 07-02 Saksbehandling 20191365 INN Hovedbrev ONSAGERS AS
 01.07.2020 07-01 Saksbehandling 20191365 INN Korrespondanse (Hovedbrev inn) ONSAGERS AS
 11.05.2020 06-02 Saksbehandling 20191365 UT PT report 08:16:40
11.05.2020 06-01 Saksbehandling 20191365 UT Realitet patent ONSAGERS AS
 30.01.2020 04-01 Saksbehandling 20191365 INN Fullmakt og erklæring
30.01.2020 02-01 Overdragelse av søknad/rettighet 2020/01248 UT GH Forespørsel ONSAGERS AS
 27.01.2020 05-04 Saksbehandling 20191365 INN Fullmakt, Erklæring Søkers rett til oppfinnelse ONSAGERS AS
 27.01.2020 05-03 Saksbehandling 20191365 INN Kopi av endringsskjema ONSAGERS AS
 27.01.2020 05-02 Saksbehandling 20191365 INN Kopi av fullmakt og erklæring vedr. 20191366 ONSAGERS AS
 27.01.2020 05-01 Saksbehandling 20191365 INN Korrespondanse (Hovedbrev inn) ONSAGERS AS
 27.01.2020 01-04 Overdragelse av søknad/rettighet 2020/01248 INN Fullmakt, Erklæring Søkers rett til oppfinnelse ONSAGERS AS
 27.01.2020 01-03 Overdragelse av søknad/rettighet 2020/01248 INN Endringsskjema ONSAGERS AS
 27.01.2020 01-02 Overdragelse av søknad/rettighet 2020/01248 INN Kopi av fullmakt og erklæring vedr. 20191366 ONSAGERS AS
 27.01.2020 01-01 Overdragelse av søknad/rettighet 2020/01248 INN Generell henvendelse ONSAGERS AS
 20.11.2019 03-01 Saksbehandling 20191365 UT Formal Examination 1 ONSAGERS AS
 20.11.2019 02-01 Saksbehandling 20191365 UT Infobrev til oppfinner ONSAGERS AS
 18.11.2019 01-03 Saksbehandling 20191365 INN fig 913557 ONSAGERS AS
 18.11.2019 01-02 Saksbehandling 20191365 INN Beskrivelse ONSAGERS AS
 18.11.2019 01-01 Saksbehandling 20191365 INN Søknadsskjema Patent ONSAGERS AS

Description, claims and drawings

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content. Description
APPARATUS FOR ESTABLISHING ABSENCE OF PAIN IN A MAMMAL TECHNICAL FIELDThe invention relates in general to an apparatus for establishing absence of pain in a mammal.BACKGROUND OF THE INVENTIONMethods and apparatus exist in the art for monitoring the nervous system of humans and other mammals, in particular for detecting pain in unconscious, non-verbal patients, e.g. patients in anaesthesia or artificially ventilated patients during surgery. Some of these methods and apparatus are used to determine if the patient needs medication due to the determined pain state in the patient.There is a need for a method and apparatus for establishing absence of pain in a mammal, in all groups from conscious and presumably healthy to the hospitalized humans or other mammals.WO 0072751 A1 relates to an apparatus and a method for monitoring the autonomous nervous system in an individual, especially for detecting pain, by utilizing spontaneous change in skin conductance. The apparatus comprises measuring equipment for measuring the skin's conductance, and storage and processing means for deriving secondary characteristics of the conductance signal . Pain in the patient may be indicated based on amplitude and frequency of fluctuations in the skin conductance signal.WO 03094726 A1 discloses a system and method of monitoring the autonomous nervous system of a sedated patient by assessing pain and a state of awakening. It describes detecting pain above a threshold and when to give analgesia.NO329287 B1 discloses a system and method of monitoring the autonomous nervous system of a sedated patient by assessing pain and a state of awakening using statistical dispersion of the skin conductance data that correlate with pain and awakening. It describes detecting pain above a threshold and when to give analgesia. Yaqi c. et al. Physiological Signal-Based Method for Measurement of Pain Intensity. Front Neurosci. 2017; vol. 11, no. 279, page 1-13, discloses a method to measure pain intensity based on multiple physiological signals, which includes the skin conductance level.Harrison d. et al. Skin conductance as a measure of pain and stress in hospitalised infants. Early Hum Dev. 2006, vol. 82, no. 9, page 603-608, discloses assessing skin conductance peaks per second before during and after heel stick (painful event) and before during and after nursing period (non-painful event). It describes that no painful stimuli like the nursing procedure can increase the peaks per sec , thus provides no method of determining absence of pain.SUMMARY OF THE INVENTIONAn object of the present invention is to provide an apparatus for establishing absence of pain in a mammal.According to the invention, the above objects are achieved by an apparatus as defined in the appended independent claims.Further advantages and characteristics of the invention are indicated in the dependent claims.BRIEF DESCRIPTION OF THE DRAWINGSThe invention will be described by example with reference to the drawings, wherein figure 1 is a schematic block diagram illustrating principles of an apparatus for establishing absence of pain in a mammal,figure 2 is a perspective view illustrating an apparatus for establishing absence of pain in a mammal, during use, andfigure 3 is a flow chart illustrating a method for establishing absence of pain in a mammal.DETAILED DESCRIPTION OF THE INVENTION Figure 1 is a schematic block diagram illustrating principles of an apparatus for establishing absence of pain in a human or other mammal, in all groups from particular a conscious and presumably healthy to the hospitalized humans or other mammals.On an area 2 of the skin on a body part 1 of the human or other mammal, sensor means 3 are placed for measuring the skin's conductance. In the case of a human, the body part 1 is preferably a hand or a foot, and the area 2 of the skin on the body part 1 is preferably the palmar side of the hand (in the palm of the hand) or the plantar side of the foot (under the sole of the foot). In the case of a non-human mammal, in particular a mammal having paws, the area of the body part may be the palmar side of a paw. The sensor means 3 comprise contact electrodes where at least one electrode (the measuring electrode) is placed on the skin area 2. In a preferred embodiment the sensor means 3 consist of three electrodes: a signal electrode, a measuring electrode and a reference voltage electrode, which ensures a constant application of voltage over the stratum corneum (the surface layer of the skin) under the measuring electrode. The measuring electrode and the signal electrode are preferably placed on the skin area 2. The reference voltage electrode may also be placed on the skin area 2, but it is preferably placed in a nearby location, suitable for the measuring arrangement concerned.In a preferred embodiment an alternating current is used for measuring the skin's conductance. The alternating current advantageously has a frequency in the range of up to 1000 Hz, corresponding to the area where the skin's conductance is approximately linear. A frequency should be selected which ensures that the measuring signal is influenced to the least possible extent by interference from, e.g., the mains frequency. In a preferred embodiment the frequency is 88 Hz. A signal generator, operating at the specified frequency, applies a signal current to the signal electrode.In the case of alternating current, the conductance is identical to the real part of the complex admittance, and therefore not necessarily identical with the inverse value of the resistance. An advantage of using alternating current instead of direct current in conductance measurement is that by this means one avoids the invidious effect on the measurements of the skin's electrical polarizing properties. The resulting current through the measuring electrode is conveyed to a measurement converter 4. This comprises a current to voltage converter, which in a preferred embodiment is a trans resistance amplifier, but in its simplest form may be a resistance, which converts the current from the measuring electrode to a voltage. The measurement converter further comprises a decomposition circuit, preferably in the form of a synchronous rectifier, which decomposes the complex admittance in a real part (the conductance) and an imaginary part (the susceptance). However, it is sufficient if the decomposition circuit only comprises means for deriving the conductance. The synchronous rectifier multiplies the measured voltage with the voltage from the signal generator. The two signals are in-phase. After multiplication, the result is according to the cosine (2u) equation, where the result is a DC component and one component at 2u frequency. In the preferred embodiment, this becomes 176 Hz. In the preferred embodiment, this synchronous rectifier is realized as an analog circuit with the required accuracy.The measurement converter 4 may also comprise amplifier and filter circuits. In the preferred embodiment the measurement converter contains low-pass filters, both at the input and at the output. The object of the input low-pass filter is to attenuate high-frequency noise, for instance coming from other medical equipment, and also to serve as anti-aliasing filter to prevent high frequency components from being received by subsequent circuits for time discretization. The output low-pass filter shall attenuate the 2u components that result from the multiplication operation in the synchronous rectifier so that only the signal near DC is used for further processing.By means of the choice of components and design details, moreover, the measurement converter is designed with a view to obtaining high sensi tivity and a low noise level.Although the measurement converter 4 has been illustrated to be external to the control unit 5 by example, it should be understood that the measurement converter may be included in the control unit 5.The control unit 5 comprises a time discretization unit 51 for time discretization of the signal from the measurement converter. The time discretization takes place at a sampling rate, which may advantageously be in the order of 20 to 200 samplings per second. The control unit further comprises an analog-digital converter 52, which converts measurement data to digital form. The choice of circuits for time discretization and analog-digital conversion implies technical decisions suitable for a person skilled in the art. In the preferred embodiment, time discretization is done in an integrated circuit, which combines oversampling, filtering and discretization. The control unit may advantageously comprise additional analog and possibly also digital inputs (not illustrated), in addition to the input from the measurement converter 4. In this case the control unit 5 can either be equipped with a plurality of analog-digital converters 52, or it can employ various multiplexing techniques wellknown to those skilled in the art in order to increase the number of analog inputs. These additional analog inputs may, for example, be arranged for additional electrodermal measurements, or for other physiological measurements which may advantageously be performed simultaneously or parallel with the electrodermal measurement, such as temperature, pulse, ECG, respiratory measurements, oxygen saturation measurements in the blood, or EEG (bispectral index).The control unit 5 also comprises a processing unit 53 for processing the digitized measurement data, storage means in the form of at least one store for storing data and programs, illustrated as a non-volatile memory 54 and a random access memory 55. The control unit 5 further comprises an interface circuit 61, which provides a first output signal 71 and optionally a second output signal 72. Optionally, the control unit 5 further comprises a further interface circuit 81, which is further connected to display unit 8. The control unit 5 may also optionally comprise a wireless communication adapter or a communication port 56 for digital communication with an external unit 10, such as a personal computer, a tablet, a mobile terminal or a smart telephone. Such communication is well-suited for loading or altering the program which is kept stored in the memory 54, 55 in the control unit, or for adding or altering other data which are kept stored in the memory 54, 55 in the control unit. Such communication is also well suited for readout of data from the memory 54, 55 in the apparatus, thus enabling them to be transferred to the external unit 10 for further, subsequent analysis or storage. In a preferred embodiment the non-volatile memory 54 comprises a read-only storage in the form of programmable ROM circuits, containing at least a program code and permanent data, and the random access memory 55 comprises a read and write storage in the form of RAM circuits, for storage of measurement data and other provisional data.The control unit 5 also comprises an oscillator (not shown), which delivers a clock signal for controlling the processing unit 53. The processing unit 53 also contains timing means (not shown) in order to provide an expression of the current time, for use in the analysis of the measurements. Such timing means are well-known to those skilled in the art, and are often included in microcontrollers or processor systems which the skilled person will find suitable for use with the present invention.The control unit 5 may be realized as a microprocessor-based unit with connected input, output, memory and other peripheral circuits, or it may be realized as a micro controller unit where some or all of the connected circuits are integrated. The time discretization unit 51 and/or analog-digital converter 52 may also be included in such a unit. The choice of a suitable form of control unit 5 involves decisions, which are suitable for a person skilled in the art.An alternative solution is to realize the control unit 5 as a digital signal processor (DSP).The control unit 5 is arranged to read time-discrete and quantized measurements for the skin conductance from the measurement converter 4, preferably by means of an executable program code, which is stored in the non-volatile memory 54 and which is executed by the processing unit 53. It is further arranged to enable measurements to be stored in the read and write memory 55. By means of the program code, the control unit 5 is further arranged to analyze the measurements in real time, i.e. simultaneously or parallel with the performance of the measurements. In this context, simultaneously or parallel should be understood to mean simultaneously or parallel for practical purposes, viewed in connection with the time constants which are in the nature of the measurements. This means that input, storage and analysis can be undertaken in separate time intervals, but in this case these time intervals, and the time between them, are so short that the individual actions appear to occur concurrently.The control unit 5 is further arranged to detecting fluctuation peaks in the timediscrete, quantized measuring signal, by means of a program code portion which is stored in the non-volatile memory 54 and which is executed by the processing unit 53.The control unit 5 is further arranged to determining the rate of the fluctuation peaks in the time-discrete, quantized measuring signal through a time interval, by means of a program code portion which is stored in the non-volatile memory 54 and which is executed by the processing unit 53.The control unit 5 is further arranged to comparing the determined rate of peaks with a predetermined reference value, by means of a program code portion which is stored in the non-volatile memory 54 and which is executed by the processing unit 53.The control unit 5 is further arranged to, if the measured rate of peaks is lower than the predetermined reference value, to provide a first output signal 71 of an interface circuit 61, as indicating the state of absence of pain in the human or other mammal, by means of a program code portion which is stored in the non-volatile memory 54 and which is executed by the processing unit 53.The control unit 5 may further be arranged to perform various steps and combinations of steps of the method as disclosed herein, in particular with reference to figure 3 below, by means of a program code portion which is stored in the nonvolatile memory 54 and which is executed by the processing unit 53.The processing unit 53, the memories 54, 55, the analog/digital converter 52, the communication port 56, the interface circuit 81 and the interface circuit 61 are all connected to a bus unit 59. The detailed construction of such bus architecture for the design of a microprocessor-based instrument is regarded as well-known for a person skilled in the art. The interface circuit 61 is a digital port circuit, which derives at least a first digital output signal 71, from the processing unit 53 via the bus unit 59 when the interface circuit 61 is addressed by the program code executed by the processing unit 53. The first digital output signal 71 indicates that the analysis of the skin conductance measurement has established the state of absence of pain in the human or other mammal.Additional output signals, schematically illustrated as a second output signal 72, may also be provided by the interface circuit 61.In a preferred embodiment the display means 8 consist of a screen for graphic visualization of the conductance signal, and a digital display for displaying the frequency and amplitude of the measured signal fluctuations. The display units are preferably of a type whose power consumption is low, such as an LCD screen and LCD display. The display means may be separate or integrated in one and the same unit.The apparatus further comprises a power supply unit 9 for supplying operating power to the various parts of the apparatus. The power supply may include a battery, preferably a rechargeable battery, or alternatively a connection to an external power supply such as a mains supply.Figure 2 is a perspective view illustrating an apparatus for establishing absence of pain in a mammal, during use.Electrodes, typically three electrodes as described above with reference to the disclosure of figure 1, are placed on the palmar side of a hand 21 of a human, hence the electrodes are not visible on figure 2. In case of a mammal having paws, the electrodes are placed on the palmar side of a paw. The electrodes are interconnected by a cable 22 to an apparatus 23 for establishing absence of pain in the mammal. The apparatus 23 includes a housing which encapsulates electronics that embodies the measurement converter 4 and the control unit 5 as described above with reference to figure 2. The housing of the apparatus is strapped to the wrist of the human or other mammal by means of a suitable wrist strap 24, preferably made of an elastic material. The apparatus 23 includes a simple operational interface including an operational element 25 that may be a touch button for switching the apparatus on and off. The apparatus 23 also includes an indicator, that may be an optical or audible indicator, or both, that provides an optical or audible indication corresponding to the first output signal 71, indicating the state of absence of pain in the mammal. Further operation of the apparatus may be provided by means of an external terminal, such as a smart telephone, corresponding to the external unit 10 and enabled to communicate with the control unit 5 in the apparatus 23 as described above with reference to figure 1.Figure 3 is a flow chart illustrating a method for establishing absence of pain in a human or other mammal.The method starts at reference 31.In measurement step 32, a skin conductance signal measured at an area of the human's or mammal's skin through a time interval is provided. To this end, skin conductance signal or EDR (electrodermal response) signal is measured by means of sensor means 3 such as contact electrodes, arranged on a body part 1 of the human or other mammal, preferably the palmar side of a hand or paw, as already has been explained with reference to figures 1 and 2 above.The skin conductance, preferably in microsiemens (uS), is time-quantized and converted to digital form, for instance by the use of equipment described with reference to fig. 1 above. A time-series of a certain duration, typically between 5 seconds and 60 seconds, and more preferably between 15 and 45 seconds, still more preferably between 25 and 35 seconds, containing skin conductance data, is acquired during step 32. For instance, at 15 seconds, with a sampling rate of 20 – 200 samples per second, the time-series may contain 300 – 3000 samples.In the subsequent peaks rate determining step 33, peaks in the skin conductance signal are detected through said time interval, and a rate of the peaks through the time interval is determined.In the peak detecting sub step of step 33, a test may be performed in order to detect the existence of valid peaks in the time-series of acquired skin conductance signal. If one or more peaks are detected, the rate of peaks is subsequently determined. If no peak is detected, the rate of peaks is considered to be zero. The existence of a valid peak may be established if the derivative of the signal changes sign through a small period in the interval. The derivative of the signal may be calculated as the difference between two subsequent sample values. In addition, it is possible to use a simple digital filter that needs to see two or more subsequent sign changes before the sign change is accepted.In the test step of establishing a valid peak it may be necessary to establish additional criteria for when a peak should be considered as valid. In their simplest form such criteria may be based on the fact that the signal amplitude has to exceed an absolute limit in order to be able to be considered a valid fluctuation. A recommended, such reference value for the conductance is between 0.005µS and 0.03 μS, preferably 0.015µS.Alternatively or in addition, it may be advantageous to base the criteria on the fact that the signal actually has formed a peak that has lasted a certain time. The criteria may also be based on the fact that the increase in the skin conductance signal value as a function of time must remain below a certain limit, typically 20 μS/s, if the maximum value is to be considered valid.Another possible condition for establishing a valid peak is that the absolute value of the change in the conductance signal from a local peak to the following local valley exceeds a predetermined value, such as between 0.01µS and 0.02 μS, preferably 0.015µS.Also, a maximum value appearing at the border of the interval, i.e. the starting point or ending point of the interval should preferably not be regarded as a valid peak. The object is thereby achieved that artifacts, which can occur in error situations such as, e.g., electrodes working loose from the skin, or other sources of noise or disturbances, does not lead to the erroneously detection of peaks.In the comparison step 34, the determined rate of peaks is compared with a predetermined reference value.The predetermined reference value is in the range of 0.00 to 0.12 peaks per second. Advantageously, the predetermined reference value may be in the range of 0.00 to 0.06 peaks per second. Still more advantageously, the predetermined reference value may be in the range of 0.00 to 0.03 peaks per second.Advantageously, the output signal is provided as indicating the state of absence of pain in the mammal if, additionally, a mean rate of the peaks through the time interval has been determined to last for a certain time period, the time period being in the range 2 to 10 minutes, or in the range 3 to 6 minutes, or in the range of 4 to 5 minutes.If the determined rate of peaks is lower than the predetermined reference value, the establishing step 35 is performed. In the establishing step 35, a first output signal 71 is provided as indicating the state of absence of pain in the mammal.Otherwise, if in the comparison step 34 the determined rate of peaks equals or is greater than the predetermined reference value, the process continues at another iteration of the measurement step 32.After the establishment of the pain absence signal in step 35, the process may end at the terminating step 36, or alternatively, it may be repeated by continuing at the measurement step 32.The process may at any time be interrupted or terminated by an operating device (not shown) or by a command input from the communication port 56.The disclosed method and apparatus results in a reliable establishment of absence of pain in a human or other mammal, in particular a conscious human or mammal as well as hospitalized humans or mammals. In case of a human, the human does not necessarily need to be a patient. In an aspect, the method and the apparatus may be a non-medical method and a non-medical apparatus. In an aspect, the method and apparatus may be particularly useful for providing confirmation of presumed absence of pain in a presumably substantially healthy human or in a human with a light disease especially treated in their homes. In an aspect, the method and apparatus may be particularly intended not to be used for the purpose of administering medicals to the human or mammal. CLAIMS1. Apparatus for establishing absence of pain in a mammal, comprising- measurement equipment for providing a skin conductance signal measured at an area of the mammal's skin, and- a control unit, configured to perform the steps of:- providing a skin conductance signal measured at an area of the mammal's skin through a time interval;- detecting peaks in the skin conductance signal through said time interval; - determining a rate of the peaks through the time interval;- comparing the determined rate of peaks with a predetermined reference value;- if the determined rate of peaks is lower than the predetermined reference value, providing an output signal as indicating the state of absence of pain in the mammal;wherein the predetermined reference value is in the range of 0.00 to 0.03 peaks per second.2. Apparatus according to claims 1,wherein the time interval is in the range 5 to 60 seconds, in the range 15 to 45 seconds, or in the range 25 to 35 seconds.3. Apparatus according to claim 1-2,wherein the output signal is provided as indicating the state of absence of pain in the mammal if also a mean rate of the peaks through the time interval has been determined to last for a certain time period, the time period being in the range 2 to 10 minutes, or in the range 3 to 6 minutes, or in the range of 4 to 5 minutes.4. Apparatus according to one of the claims 1-3,wherein said step of detecting peaks in the skin conductance signal through said time interval comprises establishing the existence of a valid peak if the derivative of the skin conductance signal changes sign through a small period in the interval. 5. Apparatus according to claim 4,wherein said derivative is calculated as the difference between two subsequent sample values.6. Apparatus according to one of the claims 4-5,wherein an additional criterion is established for when a peak is considered valid, including ensuring that the signal amplitude exceeds an absolute limit value selected from the range [0.005uS, 0.03uS].7. Apparatus according to one of the claims 4-6,wherein an additional criterion is established for when a peak is considered valid, including ensuring that the increase in the skin conductance signal as a function of time remains below 20 uS/s.8. Apparatus according to one of the claims 4-7,wherein an additional criterion is established for when a peak is considered valid, including ensuring that the absolute value of the change in the skin conductance signal from a local peak to a following local minimum exceeds a predetermined value selected from the range [0.005uS, 0.03uS].
Claims
CLAIMS (AMENDED)1. Apparatus for establishing absence of pain in a mammal, comprising- measurement equipment for providing a skin conductance signal measured at an area of the mammal's skin, and- a control unit, configured to perform the steps of:- providing a skin conductance signal measured at an area of the mammal's skin through a time interval;- detecting peaks in the skin conductance signal through said time interval; - determining a rate of the peaks through the time interval;- comparing the determined rate of peaks with a predetermined reference value;- if the measured rate of peaks is lower than the predetermined reference value, providing an output signal as indicating the state of absence of pain in the mammal;wherein the predetermined reference value is in the range of 0.00 to 0.03 peaks per second.2. Apparatus according to claims 1,wherein the time interval is in the range 5 to 60 seconds, in the range 15 to 45 seconds, or in the range 25 to 35 seconds.3. Apparatus according to claim 1-2,wherein the output signal is provided as indicating the state of absence of pain in the mammal if also a mean rate of the peaks through the time interval has been determined to last for a certain time period, the time period being in the range 2 to 10 minutes, or in the range 3 to 6 minutes, or in the range of 4 to 5 minutes.4. Apparatus according to one of the claims 1-3,wherein said step of detecting peaks in the skin conductance signal through said time interval comprises establishing the existence of a valid peak if the derivative of the skin conductance signal changes sign through a small period in the interval.5. Apparatus according to claim 4,wherein said derivative is calculated as the difference between two subsequent sample values.6. Apparatus according to one of the claims 4-5,wherein an additional criterion is established for when a peak is considered valid, including ensuring that the signal amplitude exceeds an absolute limit value selected from the range [0.005uS, 0.03uS].7. Apparatus according to one of the claims 4-6,wherein an additional criterion is established for when a peak is considered valid, including ensuring that the increase in the skin conductance signal as a function of time remains below 20 uS/s.8. Apparatus according to one of the claims 4-7,wherein an additional criterion is established for when a peak is considered valid, including ensuring that the absolute value of the change in the conductance signal from a local peak to a following local minimum exceeds a predetermined value selected from the range [0.005uS, 0.03uS].PATENTKRAV1. Anordning for å fastslå fravær av smerte i et pattedyr, omfattende- måleutstyr for å tilveiebringe et hudkonduktanssignal målt på et område av pattedyrets hud, og- en styringsenhet, konfigurert til å utføre trinnene å:- tilveiebringe et hudkonduktanssignal målt på et område av pattedyrets hud i løpet av et tidsintervall;- detektere topper i hudkonduktanssignalet i løpet av tidsintervallet;- bestemme en topprate i løpet av tidsintervallet;- sammenligne den bestemte toppraten med en forhåndsbestemt referanseverdi;- dersom den bestemte toppraten er lavere enn den forhåndsbestemte referanseverdien, tilveiebringe et utgangssignal som indikerer tilstanden av fravær av smerte i pattedyret;der den forhåndsbestemte referanseverdien er i området 0,00 til 0,03 topper per sekund.2. Anordningen ifølge krav 1,der tidsintervallet er i området 5 til 60 sekunder, i området 15 til 45 sekunder, eller i området 25 til 35 sekunder.3. Anordningen ifølge krav 1 – 2,der utgangssignalet er tilveiebragt til å indikere tilstanden av fravær av smerte i pattedyret dersom en gjennomsnittstopprate i løpet av tidsintervallet også er blitt bestemt å vare en gitt tidsperiode, tidsperioden er i området 2 til 10 minutter, eller i området 3 til 6 minutter, eller i området 4 til 5 minutter.4. Anordningen ifølge ett av kravene 1 – 3,der trinnet å detektere topper i hudkonduktanssignalet i løpet av tidsintervallet omfatter å fastsette eksistensen av en gyldig topp dersom den deriverte av hudkonduktanssignalet endrer fortegn i løpet av en liten periode i intervallet.5. Anordningen ifølge krav 4,der den deriverte beregnes som differansen mellom to etterfølgende samplingsverdier.6. Anordningen ifølge ett av kravene 4 – 5,der et tilleggskriterium fastsettes for når en topp anses gyldig, inklusive å sikre at signalamplituden overstiger en absoluttgrenseverdi valgt fra området [0,005uS, 0,03uS].7. Anordningen ifølge ett av kravene 4 – 6,der et tilleggskriterium fastsettes for når en topp anses gyldig, inklusive å sikre at økningen i hudkonduktanssignalet som funksjon av tid forblir under 20 uS/s.8. Anordningen ifølge ett av kravene 4 – 7,der et tilleggskriterium fastsettes for når en topp anses gyldig, inklusive å sikre at absoluttverdien av endringen i hudkonduktanssignalet fra en lokal topp til et følgende lokalt minimum overstiger en forhåndsbestemt verdi valgt fra området [0,005uS, 0,003uS].
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Patent classes

IPC classesA61B 5/053A61B 5/16CPC classesA61B 5/053A61B 5/16

Citations

WO 03094726 A1 (A1)WO 0072751 A1 (A1)NO 329287 B1 (B1)YAQI C. ET AL. Physiological Signal-Based Method for Measurement of Pain Intensity. Front Neurosci. 2017; vol. 11, no. 279, page 1-13. ()HARRISON D. ET AL. Skin conductance as a measure of pain and stress in hospitalised infants. Early Hum Dev. 2006, vol. 82, no. 9, page 603-608. ()

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Med Storm Innovation AS
Gimle Terrasse 4 0264 OSLO NO (OSLO Municipality, Oslo county)Org. number: 980406903Inventors
Hanne Storm
Gimle Terrasse 4 0264 OSLO NO (OSLO Municipality, Oslo county)

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ACAPO ONSAGERS AS
ACAPO ONSAGERS AS

Org. number: 932214636

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Edvard Griegs vei 1 5059 BERGEN NO (BERGEN Municipality, Vestland county)
Org. number: 932214636
Reference: 20191365

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