Support surface overlay with acoustic patient detection

Abstract

The support surface overlay system (10) includes a support surface overlay (100) and a control system (200). The support surface overlay includes at least one selectively inflatable compartment (112). The control system (200) includes a pneumatic controller (202) configured to inflate and deflate at least one selectively inflatable compartment (112). The control system (200) also includes memory (224), sensors (214), and a processor (210). The memory (224) is programmed with predetermined data indicating the operating parameters of the system (10) over time in an unloaded support surface overlay (100). The sensor (214) is configured to detect the operating parameters of the system (10) over time during inflation and / or deflation of at least one selectively inflatable compartment (112) and to provide a signal indicating this. The processor (210) is configured to compare predetermined data with data provided by the sensor (214) and determine, based on the comparison, whether a load is present on the support surface overlay (100).

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 462,480, filed on April 27, 2023, entitled "SUPPORT SURFACE OVERLAY WITH ACOUSTIC PATIENT DETECTION", and incorporates by reference the entirety thereof herein.

[0002]

[0002] The disclosed subject matter generally relates to a support surface overlay, and more particularly to a support surface overlay system having a patient detection system configured to selectively inflate and deflate air bladders and detect the presence of a load on the air bladders.

Background Art

[0003]

[0003] Support surface overlays for the alleviation and prevention of pressure ulcers are known in the art. Such support surface overlays may include first and second selectively and alternately inflatable compartments configured to reduce the contact pressure on a patient's skin. Some such support surface overlays have a limited useful life, which may be a function of the number of hours the overlay is used to support a patient. It would be desirable to provide the ability to detect and monitor the actual patient use of such support surface overlays.

Summary of the Invention

Means for Solving the Problems

[0004]

[0004] These and other features of the disclosed subject matter will be described in more detail in the section entitled "Detailed Description of the Invention" below.

[0005] In some embodiments, the subject matter described herein relates to a support surface overlay system. The system includes an air bag having a first selectively inflatable compartment and a first fluid conduit fluidly communicating with the first selectively inflatable compartment; and a control system configured to selectively inflate and deflate the air bag and to detect the presence of a load on the air bag, the control system including a pump configured to selectively inflate and deflate the first selectively inflatable compartment and a pump outlet conduit fluidly communicating with the pump; a memory configured to store predetermined data indicating first operating parameters as a function of time for the inflation and deflation of the first selectively inflatable compartment when the air bag is unloaded; a first sensor configured to detect first operating parameters as a function of time for the inflation and deflation of the first selectively inflatable compartment and to provide a data signal indicating therebetween; and a processor configured to receive a data signal from the first sensor, compare the data signal received from the first sensor with predetermined data stored in the memory according to predetermined criteria, and determine, based on the comparison, whether a load is present on the air bag.

[0005]

[0006] In some embodiments, the subject matter described herein relates to a support surface overlay system, wherein a first operating parameter includes sound in, on, or near either a first fluid conduit or a pump outlet conduit as a function of time, and predetermined data stored in memory indicates sound in, on, or near either a first fluid conduit or a pump outlet conduit as a function of time, and the first sensor includes a first acoustic sensor configured to detect sound in, on, or near either a first fluid conduit or a pump outlet conduit as a function of time.

[0006]

[0007] In some embodiments, the subject matter described herein relates to a support surface overlay system, wherein predetermined data stored in memory includes at least one of duration, timing, or pitch characteristics, and a predetermined criterion includes a predetermined difference between at least one of the duration, timing, or pitch characteristics of the predetermined data stored in memory and the corresponding duration, timing, or pitch characteristics of a sound detected by a first sensor.

[0007]

[0008] In some embodiments, the subject matter described herein relates to a support surface overlay system, the support surface overlay system further includes a discharge conduit configured to fluidly communicate with a first selectively inflatable compartment and discharge fluid from the first selectively inflatable compartment, the first operating parameter includes sound in, on or near the discharge conduit as a function of time, predetermined data stored in memory indicates sound in, on or near the discharge conduit as a function of time, and the first sensor includes a first acoustic sensor configured to detect sound in, on or near the discharge conduit as a function of time.

[0008]

[0009] In some embodiments, the subject matter described herein relates to a support surface overlay system, wherein predetermined data stored in memory includes at least one of duration, timing, or pitch characteristics, and a predetermined criterion includes a predetermined difference between at least one of the duration, timing, or pitch characteristics of the predetermined data stored in memory and the corresponding duration, timing, or pitch characteristics of a sound detected by at least one of the first and second sensors.

[0009]

[0010] In some embodiments, the subject matter described herein relates to a support surface overlay system, the support surface overlay system further includes a discharge conduit configured to fluidly communicate with a first selectively inflatable compartment and discharge fluid from the first selectively inflatable compartment, the first operating parameter includes sound in, on or near the discharge conduit as a function of time, predetermined data stored in memory indicates sound in, on or near the discharge conduit as a function of time, and the first sensor includes a first acoustic sensor configured to detect sound in, on or near the discharge conduit as a function of time.

[0010]

[0011] In some embodiments, the subject matter described herein relates to a support surface overlay system, wherein predetermined data stored in memory includes at least one of duration, timing, or pitch characteristics, and a predetermined criterion includes a predetermined difference between at least one of the duration, timing, or pitch characteristics of the predetermined data stored in memory and the corresponding duration, timing, or pitch characteristics of a sound detected by a first acoustic sensor.

[0011]

[0012] In some embodiments, the subject matter described herein relates to a support surface overlay system, where the load may include a patient.

[0013] In some embodiments, the subject matter described herein relates to a support surface overlay system, wherein the air bag further comprises a second selectively inflatable compartment and a second fluid conduit fluidly communicating with the second selectively inflatable compartment, the pump being configured to selectively inflate and deflate the second selectively inflatable compartment, and a second sensor configured to detect a second operating parameter relating to the inflation and deflation of the second selectively inflatable compartment as a function of time and to provide a data signal indicating the same, the processor further comprises receiving a data signal from the second sensor, comparing the data signal received from the second sensor with predetermined data stored in memory according to predetermined criteria, and determining, based on the comparison, whether a load is present on the air bag.

[0012]

[0014] In some embodiments, the subject matter described herein relates to a support surface overlay system, wherein the first sensor includes one of a microphone and an accelerometer.

[0015] The subject matter to be disclosed is described herein with reference to the following drawings, with an emphasis on clarity rather than scale. [Brief explanation of the drawing]

[0013] [Figure 1]

[0016] This disclosure provides an exemplary support surface overlay equipped with an acoustic patient detection system. [Figure 2]

[0017] Figure 1 is a schematic diagram of the system. [Figure 3]

[0018] This is a plot of acoustic signal versus time during the expansion, holding, and contraction phases of the inflatable compartment of the support surface overlay of the system in Figure 1 under no load. [Figure 4]

[0019] This is a plot of acoustic signal versus time during the expansion, holding, and contraction phases of the inflatable compartment of the support surface overlay of the system in Figure 1 under load. [Figure 5]

[0020] Figure 1 shows plots of acoustic signals versus time during the expansion, holding, and contraction phases of the inflatable compartment of the support surface overlay of the unloaded system in Figure 1, superimposed on the acoustic signal versus time during the expansion, holding, and contraction phases of the inflatable compartment of the support surface overlay of the unloaded system in Figure 1. [Modes for carrying out the invention]

[0014]

[0021] Where necessary, detailed embodiments of the disclosed subject matter are disclosed herein, but it should be understood that the disclosed embodiments are merely illustrative of the disclosed subject matter, which may be embodied in various forms. Accordingly, the specific structural and functional details disclosed herein should not be construed as restrictive, but merely as a basis for the claims and as a representative basis for teaching those skilled in the art how to use the disclosed technology in a variety of ways in virtually any appropriately detailed structure.

[0015]

[0022] While the disclosed subject matter is disclosed with reference to various specific embodiments, it should be understood that equivalents and substitutions may be used herein without departing from the scope of the disclosed subject matter as set forth in the claims.

[0016]

[0023] Next, the subject matter to be disclosed will be described with reference to the drawings. In the drawings, similar reference numbers refer to the same parts throughout. For clarity in describing the characteristics of the subject matter to be disclosed, the proportional relationships of elements are not maintained in the drawings. In some cases, the size of certain small parts has been enlarged for illustrative purposes.

[0017]

[0024] FIG. 1 shows an exemplary embodiment of a support surface overlay with a patient detection system 10 according to the present disclosure. The system 10 includes a support surface overlay 100 and a control system 200. As will become apparent from the following discussion, a portion of the control system 200 may be integrated with the support surface overlay 100.

[0018]

[0025] Referring to FIG. 1, the support surface overlay 100 includes an airbag 110. The airbag 110 includes at least a first selectively inflatable compartment 112 and a first fluid conduit 114 that is in fluid communication with an interior region Z1 of the first selectively inflatable compartment 112. As shown in the figure, the airbag 110 also includes a second selectively inflatable compartment 116 and a second fluid conduit 118 that is in fluid communication with an interior region Z2 of the second selectively inflatable compartment 116. The second selectively inflatable compartment 116 is optional. Therefore, the second selectively inflatable compartment 116 and components related thereto further described herein may be omitted in embodiments. In embodiments, the airbag 110 may further include additional selectively inflatable compartments and corresponding fluid conduits that are in fluid communication with their interior regions.

[0019]

[0026] The control system 200 includes a pneumatic controller 202 that includes a pump 204 and valve arrangements (e.g., a first three-way valve 206 and a second three-way valve 208). Each valve is configured to selectively introduce air or another fluid into, and release air or another fluid from, the interior regions Z1, Z2 of the first selectively inflatable compartment 112 and the second selectively inflatable compartment 116 to selectively inflate and deflate the first selectively inflatable compartment 112 and the second selectively inflatable compartment 116. A processor 210 is coupled to the pump 204, the first three-way valve 206, and the second three-way valve 208 and is configured to control their operation to effect inflation and deflation of the first selectively inflatable compartment 112 and the second selectively inflatable compartment 116 as would be recognized by one of ordinary skill in the art.

[0020]

[0027] For example, the pneumatic controller 202 may be configured to adjust a first three-way valve 206 to enable fluid communication between the output of the pump 204 and the internal region Z1 of the first selectively inflatable compartment 112, and to adjust a second three-way valve 208 to enable fluid communication between the internal region Z2 of the second selectively inflatable compartment 116 and the discharge conduit 219, thereby inflating the first selectively inflatable compartment 112 and deflating the second selectively inflatable compartment 116 by operating the pump 204 to inflate the first selectively inflatable compartment 112. In this adjustment, the second selectively inflatable compartment 116 may be deflated by exhausting or discharging the air or other fluid contained therein through the discharge conduit 219 into the environment surrounding the support surface overlay 100. With the first selectively inflatable compartment 112 in an inflated state, the pneumatic controller 202 may be configured to maintain the first selectively inflatable compartment 112 in an inflated state (i.e., a held state) by adjusting the first three-way valve 206 to isolate the internal region Z1 of the first selectively inflatable compartment 112 from the pump 204 and the discharge conduit 219. In this held state, the pump 204 is either turned off or can be repeatedly turned on and off as needed to maintain a desired pressure within the first selectively inflatable compartment 112.

[0021]

[0028] Similarly, the pneumatic controller 202 may be configured to adjust the second three-way valve 208 to enable fluid communication between the output of the pump 204 and the internal region Z2 of the second selectively inflatable compartment 116, adjust the first three-way valve 206 to enable fluid communication between the internal region Z1 of the first selectively inflatable compartment 112 and the discharge conduit 219, and operate the pump 204 to inflate the second selectively inflatable compartment 116 such that the second selectively inflatable compartment 116 is inflated and the first selectively inflatable compartment 112 is deflated. In this adjustment, the first selectively inflatable compartment 112 may be deflated by exhausting or discharging the air or other fluid therein through the discharge conduit 219 to the environment surrounding the support surface overlay 100. When the second selectively inflatable compartment 116 is in the inflated state, the pneumatic controller 202 may be configured to adjust the second three-way valve 208 to separate the internal region Z2 of the second selectively inflatable compartment 116 from the pump 204 and the discharge line to maintain the second selectively inflatable compartment 116 in the inflated state. In this holding state, the pump 204 may be turned off or may be repeatedly turned on / off as necessary to maintain a desired pressure within the second selectively inflatable compartment 116.

[0022]

[0029] The control system 200 includes a first sensor configured to detect a first operating parameter of the system 10 and provide an output indicative thereof. The control system 200 may also include a second sensor configured to detect a second operating parameter of the system 10 and provide an output indicative thereof. In embodiments, the control system 200 may include additional sensors configured to detect additional operating parameters of the system 10 and provide an output indicative thereof. In embodiments, the sensors may be, for example, acoustic sensors, such as acoustic transducers or microphones, but are not limited thereto. Similarly, the operating parameters may be, for example, sounds or noises in one or more portions of the system 10 detectable by an acoustic sensor, but are not limited thereto.

[0023]

[0030] For example, in the exemplary embodiment, the control system 200 includes a first acoustic sensor 214. The first acoustic sensor 214 is physically associated with the first fluid conduit 114 so that it can detect noise and other sounds in or around the first fluid conduit 114 and provide a signal indicating them. For example, the first acoustic sensor 214 may be disposed inside the first fluid conduit 114, mounted on the outer surface of the first fluid conduit 114, or disconnected from the first fluid conduit 114, but it can still detect noise and other sounds in or around the first fluid conduit 114. In the embodiment, the first acoustic sensor 214 and its physical association with the first fluid conduit 114 may be covered with anechoic or sound-dampening material to shield the first acoustic sensor 214 from ambient noise and other sounds in the surrounding environment of the first acoustic sensor 214 and its physical association with the first fluid conduit 114. The first acoustic sensor 214 is electrically coupled to the processor 210, thereby enabling the processor 210 to receive signals provided by the first acoustic sensor 214.

[0024]

[0031] The control system 200 in the exemplary embodiment also includes a second acoustic sensor 218. The second acoustic sensor 218 is physically associated with the second fluid conduit 118 so that it can detect noise and other sounds in or around the second fluid conduit 118 and provide a signal indicating such noise or other sounds. For example, the second acoustic sensor 218 may be disposed inside the second fluid conduit 118, mounted on the outer surface of the second fluid conduit 118, or disconnected from the second fluid conduit 118, but it can still detect noise and other sounds or vibrations in or around the second fluid conduit 118. In embodiments, the second acoustic sensor 218 and its physical association with the second fluid conduit 118 may be covered with anechoic or sound-dampening material to shield the second acoustic sensor 218 from ambient noise and other sounds in the surrounding environment of the second acoustic sensor 218 and its physical association with the second fluid conduit 118. The second acoustic sensor 218 is electrically coupled to the processor 210, thereby enabling the processor 210 to receive signals provided by the second acoustic sensor 218.

[0025]

[0032] As shown in the figure, the control system 200 further includes a third acoustic sensor 220. The third acoustic sensor 220 is physically associated with the pump outlet conduit 205 so that it can detect noise and other sounds in or around the pump outlet conduit 205 and provide a signal indicating them. For example, the third acoustic sensor 220 may be disposed inside the pump outlet conduit 205, mounted on the outside of the pump outlet conduit 205, or disconnected from the pump outlet conduit 205, but it can still detect noise and other sounds in or around the pump outlet conduit 205. In embodiments, the third acoustic sensor 220 and its physical association with the pump outlet conduit 205 may be covered with anechoic or sound-dampening material to shield the third acoustic sensor 220 from ambient noise and other sounds in the surrounding environment. The third acoustic sensor 220 is electrically coupled to the processor 210, thereby enabling the processor 210 to receive signals provided by the third acoustic sensor 220.

[0026]

[0033] As shown in the figure, the control system 200 further includes a fourth acoustic sensor 222. The fourth acoustic sensor 222 is physically associated with the exhaust conduit 219 so that it can detect noise and other sounds in or around the exhaust conduit 219 and provide a signal indicating them. For example, the fourth acoustic sensor 222 may be disposed inside the exhaust conduit 219, mounted on the outside of the exhaust conduit 219, or disconnected from the exhaust conduit 219, but it can still detect noise and other sounds in or around the exhaust conduit 219. In embodiments, the fourth acoustic sensor 222 and its physical association with the exhaust conduit 219 may be covered with anechoic or sound-dampening material to shield the fourth acoustic sensor 222 from ambient noise and other sounds in the surrounding environment of the fourth acoustic sensor 222 and its physical association with the exhaust conduit 219. The fourth acoustic sensor 222 is electrically coupled to the processor 210 so that the processor 210 can receive signals provided by the fourth acoustic sensor 222.

[0027]

[0034] The first acoustic sensor 214, the second acoustic sensor 218, the third acoustic sensor 220, and the fourth acoustic sensor 222 may be microphones, but do not need to be.

[0035] Embodiments of System 10 may include all of the above-mentioned acoustic sensors, as shown in Figure 2 and as described above, but only one of the above-mentioned acoustic sensors is required, and any of the above-mentioned acoustic sensors and all the others may be omitted in other embodiments.

[0028]

[0036] The control system 200 includes a memory 224 accessible from the processor 210. The memory 224 can be programmed with predetermined data representing one or more operating parameters of the system 10 when there is no load (e.g., a patient or other mass) on the support surface overlay 100. Such predetermined data may be real or theoretical; for example, it may be calculated based on known information regarding the construction of the support surface overlay 100 and the control system 200, or it may be determined empirically through the operation of the system 10 when the support surface overlay 100 is unloaded.

[0029]

[0037] For example, in an embodiment including a first acoustic sensor 214, memory 224 may be programmed with predetermined data showing one or more predetermined profiles of noise or other sounds in, on, or near the first fluid conduit 114, as a function of time during which the pneumatic controller 202 operates to selectively inflate and / or deflate the first selectively inflatable compartment 112 when there is no load on the support surface overlay 100. Figure 3 shows an exemplary graph illustrating such profiles of noise or other sounds versus time.

[0030]

[0038] Similarly, in embodiments including a second acoustic sensor 218, the memory 224 may be programmed with predetermined data indicating one or more predetermined profiles of noise or other sounds in, on, or near the second fluid conduit 118, as a function of time during which the pneumatic controller 202 operates to selectively inflate and / or deflate the second selectively inflatable compartment 116 when there is no load on the support surface overlay 100.

[0031]

[0039] In embodiments including a third acoustic sensor 220, the memory 224 may be programmed with predetermined data indicating one or more predetermined profiles of noise or other sounds in, on, or near the pump outlet conduit 205, as a function of time during which the pneumatic controller 202 operates (based on the adjustment of the first three-way valve 206 and the second three-way valve 208) to selectively inflate and / or deflate the first selectively inflatable compartment 112 and / or the second selectively inflatable compartment 116 when there is no load on the support surface overlay 100.

[0032]

[0040] Furthermore, in embodiments including a fourth acoustic sensor 222, the memory 224 may be programmed with predetermined data indicating one or more predetermined profiles of noise or other sounds in, on, or near the discharge conduit 219, as a function of time during which the pneumatic controller 202 operates (based on the adjustment of the first three-way valve 206 and the second three-way valve 208) to selectively deflate the first selectively inflatable compartment 112 and / or the second selectively inflatable compartment 116 when there is no load on the support surface overlay 100.

[0033]

[0041] Those skilled in the art will understand that the noise and other sound profiles as a function of time detected by the acoustic sensor when a load is present on the support surface overlay 100 will differ from the noise and other sound profiles as a function of time when no load is present on the support surface overlay 100. As will be further discussed below, such differences can be measured and evaluated to determine the presence of a user or other load on the support surface overlay 100.

[0034]

[0042] For example, the pitch, timing, duration, or other characteristics of noise or other sounds in or around the acoustic sensors when the pneumatic controller 202 inflates and / or deflates the first selectively inflatable compartment 112 and / or the second selectively inflatable compartment 116 may differ depending on whether a user, patient, or other load is present on the support surface overlay 100. This phenomenon is illustrated in the graphs shown in Figures 3 and 4, where Figure 3 is a graph of noise versus time in or around one of the above acoustic sensors when the first selectively inflatable compartment 112 and / or the second selectively inflatable compartment 116 are inflated and / or deflated with no load on the support surface overlay 100, and Figure 4 is a graph of noise versus time in or around one of the above acoustic sensors when the first selectively inflatable compartment 112 and / or the second selectively inflatable compartment 116 are inflated and / or deflated with a load on the support surface overlay 100.

[0035]

[0043] The processor 210 may be configured to compare predetermined noise and other sound data of the unloaded support surface overlay 100, stored in memory 224, with noise and other sound-pair-time data provided by the first acoustic sensor 214 and / or the second acoustic sensor 218 when the first selectively inflatable compartment 112 and / or the second selectively inflatable compartment 116 of the support surface overlay 100 are inflated and / or deflated, for example, as shown in Figure 3. The processor 210 is configured to determine that a user, patient, or other load is present on the support surface overlay 100 when the noise and other sound-pair-time data provided by the first acoustic sensor 214 and / or the second acoustic sensor 218 differs from a predetermined criterion, such as the noise and other sound-pair-time data stored in memory 224, in a predetermined manner, for example, by more than a predetermined duration, timing, or pitch, or otherwise by a predetermined difference in the shape of the noise and other sound-pair-time plot. Figure 5 shows an example of such a difference that may be sufficient for the processor 210 to determine that a user or other load is present on the support surface overlay.

[0036]

[0044] In the embodiment, other operating parameters can be detected and compared in a similar manner to the corresponding data stored in memory 224. For example, pump vibrations can be detected by one or more accelerometers and compared in a similar manner to predetermined data showing pump vibrations during inflation and / or deflation of the first and / or second selectively inflatable compartments.

[0037]

[0045] While the disclosed subject matter is disclosed with reference to various specific embodiments, it should be understood that equivalents and substitutions may be used herein without departing from the scope of the disclosed subject matter as set forth in the claims.

Claims

1. An air bag having a first selectively inflatable compartment and a first fluid conduit that is in fluid communication with the first selectively inflatable compartment, A control system configured to selectively inflate and deflate the air bag and to detect the presence of a load on the air bag, A pump configured to selectively inflate and deflate the first selectively inflatable compartment, and a controller having a pump outlet conduit that is in fluid communication with the pump. A memory configured to store predetermined data that, when the air bag is unloaded, shows a first operating parameter relating to the inflation and deflation of the first selectively inflatable compartment as a function of time. A first sensor configured to detect the first operating parameters relating to the expansion and contraction of the first selectively inflatable compartment as a function of time and to provide a data signal indicating the same, and A control system including a processor configured to receive the data signal from the first sensor, compare the data signal received from the first sensor with predetermined data stored in the memory according to predetermined criteria, and determine whether a load exists on the air bag based on the comparison, A support surface overlay system equipped with this system.

2. A support surface overlay system according to claim 1, The first operating parameter includes, as a function of time, sound in, on, or near either the first fluid conduit or the pump outlet conduit. The predetermined data stored in the memory indicates, as a function of time, the sound in, on, or near either the first fluid conduit or the pump outlet conduit. A support surface overlay system comprising a first acoustic sensor configured to detect the sound in, on, or near either of the first fluid conduit and the pump outlet conduit as a function of time.

3. A support surface overlay system according to claim 2, The predetermined data stored in the memory includes at least one of the following: duration, timing, or pitch characteristics. A support surface overlay system in which the predetermined criterion includes a predetermined difference between at least one of the duration, timing, or pitch characteristics of the predetermined data stored in the memory and the corresponding duration, timing, or pitch characteristics of the sound detected by the first sensor.

4. A support surface overlay system according to claim 2, The support surface overlay system further includes a discharge conduit configured to fluidize the first selectively inflatable compartment and to discharge fluid from the first selectively inflatable compartment, The first operating parameter includes, as a function of time, sound in, on, or near the discharge conduit. The predetermined data stored in the memory indicates the sound inside, on, or near the discharge conduit as a function of time. A support surface overlay system comprising a first acoustic sensor configured to detect the sound in, on, or near the discharge conduit as a function of time.

5. A support surface overlay system according to claim 4, The predetermined data stored in the memory includes at least one of the following: duration, timing, or pitch characteristics. A support surface overlay system in which the predetermined criteria include a predetermined difference between at least one of the duration, timing, or pitch characteristics of the predetermined data stored in the memory and the corresponding duration, timing, or pitch characteristics of the sound detected by at least one of the first and second sensors.

6. A support surface overlay system according to claim 1, The support surface overlay system further includes a discharge conduit configured to fluidize the first selectively inflatable compartment and to discharge fluid from the first selectively inflatable compartment, The first operating parameter includes, as a function of time, sound in, on, or near the discharge conduit. The predetermined data stored in the memory indicates the sound inside, on, or near the discharge conduit as a function of time. A support surface overlay system comprising a first acoustic sensor configured to detect the sound in, on, or near the discharge conduit as a function of time.

7. A support surface overlay system according to claim 6, The predetermined data stored in the memory includes at least one of the following: duration, timing, or pitch characteristics. A support surface overlay system in which the predetermined criterion includes a predetermined difference between at least one of the duration, timing, or pitch characteristics of the predetermined data stored in the memory and the corresponding duration, timing, or pitch characteristics of the sound detected by the first acoustic sensor.

8. A support surface overlay system according to claim 6, The aforementioned load is a support surface overlay system that may include a patient.

9. A support surface overlay system according to claim 1, The aforementioned air bag further, A second selectively inflatable compartment and a second fluid conduit communicating with the second selectively inflatable compartment, wherein the pump is configured to selectively inflate and deflate the second selectively inflatable compartment, A second sensor configured to detect a second operating parameter relating to the expansion and contraction of the second selectively inflatable compartment as a function of time and to provide a data signal indicating the same, Includes, The support surface overlay system further comprises a processor configured to receive a data signal from the second sensor, compare the data signal received from the second sensor with predetermined data stored in the memory according to predetermined criteria, and determine whether a load exists on the air bag based on the comparison.

10. A support surface overlay system according to claim 1, The first sensor is a support surface overlay system including one of a microphone and an accelerometer.

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