MONITORING AND EVALUATION OF DIAPERS
FIELD OF THE INVENTION
The present invention generally relates to an assembly for detecting moisture in an absorbent article, in particular in an absorbent incontinence article or an adult diaper. The invention further relates to an assembly for measuring a saturation level of a diaper. The present invention generally relates to a system for monitoring and evaluating diapers, in particular incontinence or adult diapers. The present invention further relates to a use of an assembly for detecting moisture or measuring the saturation level of a diaper, in particular in an absorbent incontinence article or an adult diaper. In addition, the present invention generally relates to a method for applying an assembly for detecting moisture or measuring the saturation level of a diaper, in particular in an absorbent incontinence article or an adult diaper. Additionally, the present invention generally relates to a method for monitoring and evaluating diapers, in particular adult diapers. The invention is not limited to any particular type of diapers.
BACKGROUND OF THE INVENTION
Diapers, in particular incontinence or adult diapers, are commonly used by people requiring incontinence aids that are not able to change incontinence material themselves and alert the environment in the case of an incontinence incident. This results in exposure of this person to urine and fecal matter, which produces discomfort. In case of prolonged exposure it may even lead to morbidity (e.g. urinary tract infection), which in untreated cases may also lead to mortality.
As a consequence these people require to be monitored carefully by caregivers for instance relatives or nurses. This becomes cumbersome in situations where multiple of these people are housed together and are monitored by a limited group of caregivers, like patients in institutions such as hospitals, nursing homes and geriatric institutions. Therefore, these institutions usually operate on the basis of routines and schedules that allow for an efficient and regular changing event typically once every hours, to limit the maximal duration of exposure. Furthermore, it is common that patients in these homes are provided with absorbent pull up pants with an absorbent capacity that considerably (e.g. oftentimes by as much as tenfold) exceeds the required capacity for the applied schedule.
The main disadvantage of this approach is that it leads to considerably more nursing time, waste and costs than is required, because absorbent pull up pants that are unused and not used up to the advised saturation level (i.e between 50% and 75% according to standard ISO 11948-1) are being changed. Furthermore, this approach does not prevent exposure of the patient to moisture from urine and/or fecal matter, since the incontinence incident can occur instantly after a changing event and the amount of expelled urine and fecal matter may change quite rapidly in time due to several factors like illness, dietary changes and weather conditions.
Various incontinence detectors for absorbent articles are known. US5903222A, describes a device that detects moisture by detecting a change in capacitance, by means of an electronic circuit. When moisture is detected the device alerts the caregiver. The advantage is that these devices can help prevent the exposure of the patient to moisture from urine and/or fecal matter. The disadvantage is that practical experience showed that incontinence incidents with small amounts of moisture or other events like perspiration may lead to a false alert, which can result in more nursing time than necessary, waste and costs.
OBJECT OF THE INVENTION
It is an object of the present invention to provide an apparatus, system and method for monitoring and evaluating diapers that is not subject to the described disadvantages.
SUMMARY OF THE INVENTION
According to one aspect of the invention, there is therefore provided an assembly for detecting moisture in an absorbent article as set out in the appended claims. The assembly comprises a sensor and an apparatus arranged for co-operation with the sensor for detecting moisture. The sensor comprises at least two sensing elements and a flexible substrate on which the at least two sensing elements are arranged at a distance of at least 3 mm, preferably at least 5 mm, even more preferably at least 1 cm, from one another. Such an assembly is less prone to produce a false alert as a consequence of incontinence incidents with small amounts of moisture or other events like perspiration.
Sensing elements arranged on a flexible substrate allow the sensing element to be placed in close proximity to the external surface of an absorbent article and for the sensing elements to stay in the same location with respect to the absorbent article. Such close proximity between the sensing elements and the outer surface of an absorbent article results in each of the sensing elements to form a capacitor with the portions of the external surface of the absorbent article that lie directly opposite to the sensing element and the absorbent material that lies between these portions of the external surface to provide an electrical resistance. When the absorbent article is exposed to a conducting fluid that covers an area comprising both sensing elements, the electrical resistance of the wetted absorbent material located between the portions of the external surface is decreased and the build-up of charge at the portions of the external surface of the absorbent article is facilitated. Consequently, the capacitance increases to a large extent. In such an arrangement the distance between the sensing elements determines the amount of fluid that will trigger a large increase in capacitance. It has now been observed that a distance of at least 3 mm, preferable 5 mm and even more preferably 1 cm provides a good specificity.
Surprisingly, such an assembly also provides a higher sensitivity as a consequence of a higher signal to noise ratio than known devices or assemblies. Furthermore, it results in a low capacitance (e.g. 1-100 pF), which has the benefit that measurements consume less energy.
Each sensing element is advantageously arranged as a planar plate and may have different sizes or shapes. For instance a simple rectangular or circular shape of about 1 to 5 cm2 provides a practical size for these types of applications. A smaller size increases the chances that the surface of the sensing element is not proximal enough to the external surface of the absorbent article. A larger size increases the capacitance and energy usage. Furthermore, large sensing elements could result in discomfort in certain situations.
In an advantageous embodiment the flexible substrate has a first attachment means for attaching the sensor to an outer surface of an absorbent article. The benefit is that such a flexible substrate can then be placed on the absorbent article in different locations. This allows the use with various types of absorbent articles and eliminates the need to integrate it with the absorbent article. It can therefore be used with various standard types of absorbent articles. Such first attachment means may comprise an adhesive. The benefit of an adhesive is that it typically has a very small thickness and therefore results in a close proximity between the sensing elements and the absorbent article.
Advantageously, the flexible substrate comprises a second attachment means arranged for removably attaching the apparatus to the sensor, to allow reuse of the apparatus with another sensor. The second attachment means may comprise an electrically conductive material configured for providing an electrical connection between the apparatus and the sensor. This would eliminate the need to provide for additional means for providing electrical communication between the sensor and the apparatus. For example, a male or female end of a snap fastener may be used as a second attachment means.
The apparatus advantageously comprises an electric circuit. The circuit may be configured for charging the sensing elements and determining an electrical potential difference between the at least two sensing elements. This electrical potential difference is representative for the capacitance, but is simpler than calculating the actual capacitance and can be performed before reaching an equilibrium. Preferably, the circuit is further configured for detecting the electrical potential difference after a predetermined charging time of the at least two sensing elements, and can therefore be detected at predetermined time intervals. Preferably, the circuit is further configured to provide a signal when the electrical potential difference exceeds a threshold value. The benefit of an assembly according to the invention is that it enables using an absolute threshold value, because it is relatively insensitive to other external factors. It therefore does not need to be calibrated each instance or be compared to a previous measurement (e.g. taken at predetermined time intervals).
The assembly may further comprise communication means for communicating a moisture status. For instance, an audible alarm, a visible sign such as light or a display, or wireless communication to a handheld device may inform a caretaker that the absorbent article requires to be changed. This may be provided as a result ofthe circuit providing a signal after the electrical potential difference exceeds a threshold value.
The assembly for detecting moisture may further comprise a diaper, comprising an absorbent material, wherein the apparatus is arranged to detect a saturation level of the diaper. This enables changing the diaper at just the right moment, so that it is not changed pre-maturely and before it becomes over-saturated. For example, the at least two sensing elements may be arranged at a position configured to be along a perimeter of a wetted area of the absorbent material corresponding to a saturation level between 50 and 95%, more preferably between 65 and 85% and even more preferably between 70 and 75%. Such placement makes sure that the apparatus only detects moisture once the portions ofthe absorbent article that lies directly opposite to the sensing element and the absorbent material that lies between these portions are exposed to a conducting fluid. The benefit of such an arrangement is that the sensor and/or apparatus do not need to be altered for different capacities or form-factors of the diaper or even another type of absorbent article. It is just the placement of the sensor that affects the saturation level that can be detected.
Typically, absorbent material comprises uniformly distributed super absorbent polymer (SAP) and cotton or similar materials having the same purpose. The purpose being that the SAP provides the main fluid absorbing capacity and that the cotton provides the distribution of fluids by means of its capillary action. The SAP however hinders the further displacement of fluid by the cotton as long as its absorbent capacity has not been reached. Therefore, in situation where the absorbent material is uniformly distributed over a volume having a constant width and a constant thickness, the travelled height has substantially a linear relationship with the saturation level. This height then provides a convenient reference point for the saturation level. Consequently, it is preferred that the absorbent article or the diaper comprises an absorbing portion comprising absorbent material that is uniformly distributed over the absorbing portion. Advantageously, the absorbing portion extends over a volume having a constant width and a constant thickness.
Beneficially, the absorbing portion (or the absorbent material) comprises a crotch portion and a waist portion extending from the crotch portion towards a waistband of the diaper, wherein the waist portion comprises the at least two sensing elements and wherein the crotch portion is free of the at least two sensing elements. Typically, the absorbent material has a geometric center in the crotch portion and advantageously extends symmetrically from the crotch portion to the front and to the back of the diaper. By so doing, a percentage ratio of the wetted area and the total area of the absorbent material corresponds to the saturation level. This allows to determine where to place the sensing elements in order to correspond to a certain saturation level.
Regularly, the waist portion comprises a ventral portion. In such cases the sensor may be configured to be placed at the ventral portion to provide for the most comfort. Each of the at least two sensing elements comprise a geometric center, and may further be arranged such that an axis comprising the geometric centers is substantially parallel to a perimeter of the wetted area of the absorbent material during use.
Typically, saturation levels as indicated above are reached when moisture reaches a predetermined distance between 12 cm and 6 cm or 11 cm and 7 cm below the front waist portion of the absorbent material, respectively. An assembly according to the present invention therefore does not require various inputs to function, like the moment that a changing event occurs or the capacity of the worn incontinence material because it detects the relevant chosen saturation level, e.g. 75%, as it occurs. Furthermore, there is no risk with respect to erroneous inputs, the temporary dysfunction or disconnection of the apparatus or a false estimation algorithm. A further advantage is that an assembly according to the invention can be fully integrated and be located at a comfortable location near the waist of the patient.
Optionally, the assembly comprises an array of sensors that are arranged at different heights along the waist portion, so that the positions of the sensors on the diaper correspond to perimeters of a wetted area of the absorbent material corresponding to different saturation levels, for example between 50 and 95% or between 50 and 75%. As the absorbent material will trap increasing amounts of moisture, the wetted area will expand, thereby advancing its perimeter through the absorbent material. By so doing, the perimeter of the wetted area will consecutively reach positions of consecutive sensors in the array. The array of sensors can be attached to a single flexible susbtrate. Such an array allows the selection of a saturation level at which the environment is notified and can be used to predict when a changing event would be required.
The housing of the apparatus is preferably arranged to be waterproof and splashproof and even more preferably to be waterproof and watertight. The housing can be composed of any non-metallic and non-conductive material. Preferably, it substantially comprises a plastic, which beneficially can be disinfected.
The assembly advantageously comprises communication means. The communication means may comprise any means suitable for notifying the environment that the diapers have reached the predetermined saturation level. These may comprise direct communication means like audible alarms, visible alarms and haptic feedback means. In a preferred embodiment of the invention, the apparatus comprises indirect communication means like WiFi, Bluetooth, 2G/3G/4G etc. that are suitable to wirelessly transmit a signal to a user-terminal, like a server, mobile device or any other receiver that the caregiver can interact with. Such a system for monitoring and evaluating diapers comprising at least one user-terminal equipped with indirect communication means and at least one apparatus equipped with indirect communication means allows the communication between the at least one user-terminal and the at least one apparatus. This user-terminal can be used to develop an incontinence care plan comprising selecting the appropriate capacity of the absorbent article and accordingly plan an appropriate changing moment. Furthermore, it can be used by institutions as input for supply management.
According to another aspect of the invention, there is provided a use of the above assembly for monitoring and evaluation of diapers, comprising applying the assembly on a diaper such that the at least two sensing elements are arranged to detect a saturation level of between 50% and 95%, more preferably between 65% and 85% and even more preferably between 70 and 75%. This can be achieved when the at least two sensing elements are positioned substantially along a perimeter of a wetted area of an absorbent material corresponding to a saturation level between 50 and 95%, more preferably between 65% and 85%, even more preferably between 70 and 75%. Typically, the moisture sensing elements would have to be positioned between 12 cm and 6 cm or 11 cm and 7 cm below the front waist portion of the absorbent material. Preferably, the sensing elements are positioned to overlap a waist portion of the absorbent material such that the crotch portion is free of the sensing elements.
According to another aspect of the invention, there is provided a method for detecting a saturation level of a diaper comprising placing an assembly according to the invention such that the at least two sensing elements are positioned to detect a saturation level of between 50% and 95%, more preferably between 65% and 85% and even more preferably between 70 and 75%. This can be achieved when the at least two sensing elements are positioned substantially along a perimeter of a wetted area of an absorbent material corresponding to a saturation level between 50 and 95%, more preferably between 65% and 85%, even more preferably between 70 and 75%. This can be achieved when the at least two sensing elements are positioned substantially along a perimeter of a wetted area of an absorbent material corresponding to a saturation level between 50 and 95%, more preferably between 70 and 75%. Typically, the moisture sensing elements then have to be positioned between 12 cm and 6 cm or 11 cm and 7 cm below the front waist portion of the absorbent material. Preferably, the sensing elements are positioned to overlap a waist portion of the absorbent material such that the crotch portion is free of the sensing elements.
According to another aspect of the invention, there is provided a method for monitoring and evaluation of diapers, the method comprising:
• selecting a wearing time period for diapers, the diapers comprising absorbing materials having a first moisture absorbing capacity, the diapers being changed at changing events occurring upon expiry of the wearing time period, • at each changing event, attaching the sensor to the diaper at a predetermined position corresponding to a saturation level of the absorbing material of the respective diaper, • monitoring the assembly and, upon the assembly detecting a saturation level, recording a time elapsed to reach the saturation level and determining a second moisture absorbing capacity of the absorbing material of the diaper on the basis of the time elapsed to reach the saturation level.
The first capacity can have any desired capacity. Preferably, a calibration capacity is chosen which is relatively small for the wearing time period. This enables to quickly determine a second capacity that is more suitable for the chosen wearing time period. This second capacity can be chosen based on a function that uses historical data of the patient, the population, epidemiologic data, available diaper capacities and other types of data that may be relevant to choose a suitable capacity. For instance, the new capacity can be determined based on a function factoring in the wearing time period, the first capacity and the time it took to reach the saturation level of the first capacity.
One advantage of methods according to aspects of the invention is that the absolute moisture absorbing capacity of the absorbing material need not be known for the method to function properly. It may be sufficient for the method to function when it is known how the absorbing materials of different diapers are ranked in terms of moisture absorbing capacity. This will make it much easier for an operator to use the method.
Advantageously, the wearing time period is a fixed time period throughout the different changing events. Advantageously, the moisture sensing apparatus is reused at each changing event.
Preferably, the method also comprises determining a third capacity of the absorbing material of the diaper smaller than the first or second capacity determined at a preceding changing event, if, upon expiry of the wearing time period, no saturation level was detected by the moisture sensing apparatus. This also enable the lowering of the chosen capacity when the saturation is never reached before the end of the wearing time period. This can for instance occur after a period of illness, when urine secretion was higher than regular for this patient. In a practical embodiment, the functions that determine the suitable capacity are arranged to limit the continuous changing of capacity, which may occur when the saturation levels of two consecutive capacity levels are relatively far apart.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be explained in greater detail with reference to the figures, in which equal or similar parts are indicated by the same reference signs, and in which:
Figure 1 shows a back view of an embodiment of a sensor of an assembly according to the invention; and
Figure 2 shows a front view of an embodiment of an apparatus of an assembly according to the invention; and
Figure 3 shows a perspective view of an embodiment of a diaper comprising a flexible substrate of an assembly according to the invention; and
Figure 4 shows a perspective view of an embodiment of a diaper comprising an apparatus of an assembly according to the invention; and
Figure 5 shows a perspective view of a saturation level of a diaper; and
Figure 6 shows a schematic representation of a method according to the invention.
DETAILED DESCRIPTION
Figure 1 relates to a sensor 101 of an assembly according to a preferred embodiment of the present invention. Figure 2 relates to an apparatus 201 of an assembly according to a preferred embodiment of the present invention. Figures 3 and 4 relate to a diaper 301 of an assembly according to a preferred embodiment of the present invention. Figures 5 relates to a saturation level 305 of a diaper. Figure 6 relates to a preferred method 401 according to the invention.
The assembly for detecting moisture in an absorbent article, in particular an incontinence absorbent article or an adult diaper 301, comprises a sensor 101 for sensing moisture in the absorbent material 302 of diaper 301. The sensor 101 comprises a pair of sensing elements 103, which are arranged as a coplanar-plate capacitor on a flexible substrate 102. The flexible substrate 102 may comprise a first attachment means (not shown), such as an adhesive, to attach the sensor 101 to the diaper 301. The sensing elements 103 are spaced apart to provide a gap between the sensing elements of at least 3 mm, preferably at least 5 mm.
The assembly further comprises an apparatus 201 arranged for co-operation with the sensor 101 for detecting moisture. Apparatus 201 can comprise an electric circuit arranged to detect a difference in electric potential between the sensing elements 103. The sensor 101 and the apparatus 201 may comprise co-operating second attachment means 104, which allow the apparatus 201 to be removably attached to the sensor 201. These second attachment means 104 means may comprise an electrically conductive material providing an electrical connection between the sensor and the apparatus. An example of such second attachment means may comprise the male or female part 104 of a snap fastener. In such a case the apparatus would comprise the corresponding part 204 of the snap fastener.
The at least two sensing elements 103 of the sensor 201 may be attached on a diaper 301 at a position configured to correspond to a perimeter of a wetted area of the absorbent material 302 when a desired saturation level 305 is reached, e.g. of 70%. The wetted area covers a percentage of the area of the absorbent material 302 (i.e. the absorbing portion) corresponding to the saturation level. The absorbent material advantageously extends over an absorbing portion such that it has a geometric center in the crotch portion 306. A percentage ratio of the wetted area 303 and the total area of the absorbent material 302 corresponds to the saturation level 303. The sensor is preferably arranged in a ventral portion 304 of the waist portion of the diaper, but may alternatively also be placed in a dorsal portion 303 of the waist portion of the diaper. The apparatus 101 may be removably attached to the sensor by means of for instance snap fasteners 104, 204.