Patent Description:
Patients in hospitals and other clinical or care settings with chronic or short-term mobility issues are often unable to move themselves between stretchers, beds and operating tables. Hospital or care home staff are frequently required to move patients for washing and cleaning, to undergo a medical procedure or to move between beds. This can result in injury for both patients and staff, particularly for heavier patients.

Mattresses for handling and moving patients which are immobile or have limited mobility are widely employed in hospitals and care settings. Existing transfer mattresses typically include two flexible material sheets with an upper sheet positioned above and stitched to a lower sheet to define a plenum chamber between the sheets. The lower sheet has multiple perforations and the mattress includes an inlet valve for inflation. In use, the patient is placed on the upper sheet, the inlet valve is connected to an air pump and the mattress is inflated. This lifts the upper sheet and patient away from the underlying surface (bed, table, stretcher etc) as the mattress inflates. Air escaping through the perforations on the lower sheet creates a cushion of air underneath the mattress, reducing contact and friction between the mattress and the underlying surface. This allows the mattress and patient to be more easily pulled across the surface. Examples of such mattresses are disclosed in <CIT>, <CIT>, <CIT> and <CIT>. <CIT> discloses an air mattress comprising a bladder and a patient support for transferring patients with a low friction coating to improve sliding.

Owing to the continuous escape of air through the perforations, these transfer mattresses require a constant flow of air during use. They must therefore remain connected to the air pump throughout the transfer procedure. Air pumps are typically noisy and bulky as they are required to sustain a constant high flow rate. Pumps may also be expensive and require regular maintenance. Where a patient is being transported to or from an MRI scan, the pump cannot be brought into room owing to the MRI magnet, thus requiring long and unwieldy tubing which may obstruct and hinder patient or staff movement. Furthermore, if the patient is being moved into a sterile environment (for example an operating theatre) then the non-sterile air within the mattress, pipe and pump increases the risk of contamination.

The present invention seeks to provide a patient transfer mattress which facilitates patient transfer without requiring a continuous airflow.

Viewed from a first aspect the present invention provides an inflatable mattress for patient transfer comprising: an elongate top sheet having a head end, a foot end and a longitudinal axis extending therebetween; an elongate bottom sheet having substantially the same size as the top sheet and positioned adjacent to the top sheet, wherein the top and bottom sheets are joined around their perimeter to define a cavity between the top and bottom sheets; and a valve in fluid communication with the cavity, wherein the valve includes a port on an external surface of the mattress to enable the cavity to be inflated or deflated, wherein the inflatable mattress comprises a low friction material provided on at least a portion of an outwards facing surface of the bottom sheet, or optionally on a cover sheet attached to and covering at least a portion of the bottom sheet, wherein the top and bottom sheets are joined within the cavity by one or more baffles. The mattress further comprises one or more grip pads composed of a high friction material disposed on the outwards facing surface of the bottom sheet or, where present, the cover sheet. The grip pads are positioned adjacent or on the baffles.

The low friction material on the outwards facing surface of the bottom sheet or on the cover sheet advantageously reduces friction between the underlying substrate and the mattress, facilitating movement of the mattress across the substrate. The baffles also advantageously reduce the surface area of the bottom sheet (or cover sheet) which is in contact with the substrate when inflated, which further reduces friction between the mattress and underlying substrate. Unlike existing transfer mattresses which rely on a perforated bottom sheet and constant airflow to create an air cushion, the mattress of the present invention does not require continuous airflow once inflated. This eliminates the need for a high-power pump to be used continuously during patient transfer and moved with the mattress. The mattress of the present invention can be inflated using a lower powered pump or handheld pump.

The bottom sheet may be composed of or integrally comprise the low friction material on an outwards facing surface, or the low friction material may be applied as a coating to the outwards facing surface. Alternatively the low friction material may be provided on a separate cover sheet which is attached to and covers at least a portion of the bottom sheet.

The cover sheet may be attached to the bottom sheet by an adhesive, welding, or stitching.

The mattress preferably has a size sufficient to support the entire body of a supine or prone patient. The mattress is elongate and has a length extending along a longitudinal axis from a head end to a foot end, and a width extending along a transverse axis perpendicular to the longitudinal axis. The mattress may have a length similar to the height of an adult. For example, the mattress may have a length of between <NUM> and <NUM>. The mattress may have a width of between <NUM> and <NUM>, e.g. about <NUM>. The width may be substantially constant along the entire length or may decrease at or towards the head and/or foot ends.

The baffles are preferably elongate. Where the baffles are elongate, they may extend in a generally longitudinal or transverse direction.

The baffles are preferably elongate and preferably extend in a generally transverse direction. Transversely extending baffles advantageously enable the mattress to be bent or folded in a transverse direction whilst maintaining airflow throughout the cavity. The top and bottom sheets may be attached together at the baffles by stitching or welding. Preferably the top and bottom sheets are attached together at the baffles by welding.

The mattress may comprise a set of hip joint baffles in a hip joint area. The hip joint area has a longitudinal position which corresponds approximately with the position of a patient's hips when they are lying on the mattress. Preferably the hip joint area is positioned approximately halfway between the head end and foot end of the mattress.

The set of hip joint baffles may comprise one or more rows of transversely oriented baffles. The rows are preferably substantially parallel. Preferably the set of hip joint baffles comprises <NUM>-<NUM> rows of transversely oriented baffles. Each row may have a transverse extent of up to <NUM>% of the mattress width. Preferably each row has a transverse extent of around <NUM>% of the mattress width. Preferably each row is aligned centrally with respect to the mattress width to define an edge region free from baffles. Each row may have a single elongate baffle or may have multiple transversely spaced baffles. For example, each row may have between <NUM> and <NUM> transversely spaced baffles. Each baffle may have an equal or different transverse extent.

The mattress may comprise a set of knee joint baffles in a knee area. The knee area has a longitudinal position which corresponds approximately with the position of a patient's knees when they are lying on the mattress. Preferably a longitudinal distance between the head end and the knee area is approximately three times the longitudinal distance between the foot end and the knee area.

The set of knee joint baffles may comprise one or more rows of transversely oriented baffles. The rows are preferably substantially parallel. Preferably the set of knee joint baffles comprises <NUM>-<NUM> rows of transversely oriented baffles. Each row may have a transverse extent of up to <NUM>% of the mattress width. Preferably each row has a transverse extent of around <NUM>% of the mattress width. Preferably each row is aligned centrally with respect to the mattress width to define an edge region free from baffles. Each row may have a single elongate baffle or may have multiple transversely spaced baffles. For example, each row may have between <NUM> and <NUM> transversely spaced baffles. Each baffle may have an equal or different transverse extent.

The hip joint and knee joint baffles advantageously enable the mattress to be bent or folded in a transverse direction (i.e. in a direction substantially parallel to the rows of baffles) in the hip and/or knee regions. The mattress can therefore be used on hospital beds equipped with a moveable back rest portion, and can also be used to transfer a patient between a bed and a chair.

The mattress may comprise one or more support baffles. The support baffles preferably extend transversely and may have a curved shape (e.g. a concave or convex shape). The support baffles are preferably aligned centrally with respect to the width of the mattress and have a transverse extent of between <NUM>% and <NUM>% of the mattress width. This defines an edge region which is free from baffles. A curved shape prevents or limits folding of the mattress at the support baffles and may increase comfort for patients with back or chest injuries.

The support baffles increase the structural rigidity of the mattress and prevent deformation during inflation or overinflation. The baffles are preferably positioned over a central section of the mattress, defining an edge region around the perimeter of the mattress which is free from baffles. When inflated, the edge region provides a raised cushion around the central section to increase the comfort and safety of the patient.

The low friction material may be selected from a group consisting of polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP) and silicone.

The grip pads are preferably composed of a high-friction material such as rubber or neoprene. The grip pads may be attached to the bottom sheet or cover sheet by stitching, welding or an adhesive.

The grip pads are positioned adjacent or on baffles, (i.e. at or around areas where the bottom sheet is joined to the top sheet). This advantageously means that when the mattress is deflated, the grip pads will contact the substrate, thus increasing friction between the mattress and substrate. This helps to anchor the mattress when deflated and prevent slippage. This enables the mattress to be left underneath a patient during a procedure. When the mattress is inflated, the grip pads will be raised away from and will no longer contact the substrate.

Preferably the grip pads are positioned under high mass points of the patient, i.e. the points where a patient lying on the mattress exerts greater pressure. For a supine patient this would include the shoulders, lower back, calves and heels. This helps ensure that the pressure applied by the patient keeps the mattress anchored to the bed or table when deflated. For example, the mattress may comprise two shoulder grip pads, a lower back grip pad, two calf grip pads and two heel grip pads.

The mattress may further comprise a side sheet attached to the perimeter of both the top and bottom sheets. The mattress may further comprise baffle panels within the cavity and attached to the first and second sheets at the baffles. Preferably the top and bottom sheets are attached directly to each other around the perimeter and at the baffles without a side sheet or baffle panels. This simplifies the manufacturing process and reduces the number and length of joins between different sheets of material, thus reducing the risk of stitching/welding failure and leaks at the joins.

The top and bottom sheets may be composed of the same material or a different material. Preferably the top and bottom sheets are composed of the same material. This advantageously increases the strength of bonding between the top and bottom sheets where they are joined together by welding. Where the top and bottom sheets are composed of the same material, the bottom sheet may have an additional coating of a low friction material on the outwards facing surface. The bottom sheet may have a greater thickness than the top sheet to provide additional protection against puncture or wear. The top and/or bottom sheets may be composed of a material selected from a group consisting of polyvinyl chloride, polyethylene, polypropylene, polyurethane, thermoplastic polyurethane and synthetic or natural rubber. Preferably the top and bottom sheets are composed of a thermoplastic polyurethane.

The top sheet may further comprise a coating over an upper surface. The coating may be in the form of flocking, or may be a soft material coating such as felt matting to increase patient comfort. Alternatively the coating on the upper surface may be a waterproof or non-absorbant surface which can be easily cleaned and/or disinfected. The coating on the upper surface may be a nylon coating.

The valve may be located between the top and bottom sheets (i.e. sandwiched between the two sheets along the perimeter of the mattress) or may be provided in the top or bottom sheet. Preferably the valve is provided in the top sheet for ease of access. The top sheet may include additional reinforcing material around the valve to reduce the risk of tearing or damage as an inflation pipe is attached or detached. Preferably the valve is positioned towards a foot end corner of the top sheet.

The mattress may further comprise one or more handles arranged around a perimeter to aid staff handling or moving the mattress when in use. The handles may be stitched or welded onto the mattress or may be formed integrally with the top and/or bottom sheets. There may be any number of handles spaced around the perimeter of the mattress. The handles may be positioned on the long edges of the mattress, or on the short edges of the mattress, or on both. Preferably there are between <NUM> and <NUM> handles on each long edge and between <NUM> and <NUM> handles on each short edge. Particularly preferably there are <NUM> handles on each long edge and no handles on each short edge. Alternatively the handles may comprise one or more elongate strips which extend along an edge of the mattress and are attached to the mattress at multiple points to define one or more grippable handles.

The mattress may further comprise one or more pairs of restraining strap loops provided around a perimeter of the mattress to receive and attach restraining straps. One or more restraining straps may be provided which are attachable to the loops to secure a patient during transport to reduce the risk of a patient falling from the mattress.

Viewed from a second aspect the present invention provides a method of forming the option of the inflatable mattress for patient transfer, comprising: taking two similarly sized sheets of flexible rubber or thermoplastic material; applying a low-friction coating to one side of a first sheet to form a bottom sheet; attaching one or more grip pads to the bottom sheet; implanting a valve into a second sheet to form a top sheet; overlaying the top sheet on the bottom sheet such that the coated side of the bottom sheet is oriented away from the top sheet; cutting both sheets to a desired shape; and welding the top and bottom sheets together around a perimeter and at one or more baffles to form a cavity between the two sheets.

The perimeter may include one or more handle portions and the cutting step may include cutting one or more handle holes into the first and second sheets.

The perimeter may include one or more strap loops and the cutting step may include cutting one or more strap holes into the first and second sheets. The method may further comprise attaching restraining straps to the strap loops.

The two sheets may be welded together by a laser, friction, high-frequency or ultrasonic welding process. The two sheets may also be welded together chemically, using a solvent or an adhesive. Preferably the two sheets are welded using high-frequency or ultrasonic welding.

Viewed from a third aspect the present invention provides a method for forming the second option of the inflatable mattress for patient transfer, comprising: taking two similarly sized sheets of flexible rubber or thermoplastic material; implanting a valve into a first of the two sheets to form a top sheet; overlaying the top sheet and the second sheet; cutting both sheets to a desired shape; welding the two sheets together around a perimeter and at one or more baffles to form an inflatable pad having a cavity between the two sheets; positioning a cover sheet comprising a low friction material over an outwards facing surface of the second sheet; attaching one or more grip pads to an outwards facing surface of the cover sheet; and stitching the cover sheet to the inflatable pad around a perimeter and at the one or more baffles.

The method may further comprise attaching one or more handle strips around the perimeter.

Viewed from a fourth aspect the present invention provides a method for moving a patient, comprising: placing a mattress as hereinbefore described on a substrate; positioning a patient on the top sheet of the mattress with their head towards the head end and their feet towards the foot end; inflating the cavity by forcing air in through the valve; repositioning the mattress and patient by pulling or pushing the mattress across the substrate or between the substrate and another surface; and opening the valve to deflate the mattress once the patient has been moved to the desired position.

Specific implementations of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:.

Referring initially to <FIG> and <FIG>, an inflatable mattress <NUM> is shown in an inflated configuration. The inflatable mattress <NUM> has an elongate generally rectangular shape extending along longitudinal axis X. The mattress <NUM> has a size sufficient for the entire body of an adult patient <NUM> in a supine position to be positioned on the mattress <NUM>. In this particular embodiment the mattress has a maximum width of <NUM> and a length of <NUM>.

The mattress includes a top sheet <NUM> (shown in <FIG> and <FIG>) and a bottom sheet <NUM> (shown in <FIG>) which has substantially the same size and shape as the top sheet <NUM> and is positioned underneath the top sheet <NUM>. The top and bottom sheets <NUM>, <NUM> are composed of thermoplastic polyurethane.

In this particular embodiment, the top sheet <NUM> and bottom sheet <NUM> are welded together around the perimeter <NUM> of the mattress <NUM> to define a cavity <NUM> (not shown in <FIG>) between the top and bottom sheets <NUM>, <NUM>. This bonding method simplifies the manufacturing process and reduces the risk of failure or leaks around the perimeter <NUM>.

The mattress <NUM> has a head end <NUM> and a foot end <NUM>. Although the mattress <NUM> has a generally rectangular shape, the mattress <NUM> tapers inwardly slightly towards the head end <NUM> to give a streamlined shape and to reduce the risk of the head end <NUM> of the mattress <NUM> catching or snagging on surrounding furniture or equipment during movement.

A series of handles <NUM> are spaced around the perimeter <NUM> of the mattress <NUM> on each long edge (i.e. the edges running generally parallel to the longitudinal axis X). In this particular embodiment there are four handles <NUM> spaced along each long edge, with no handles on the short edges (i.e. the edges running generally perpendicular to the longitudinal axis X). The handles <NUM> are formed integrally with the perimeter <NUM> as the top and bottom sheets <NUM>, <NUM> are welded together.

A valve <NUM> is provided towards one corner of an upper sheet <NUM> towards the foot end <NUM>. The valve <NUM> is positioned towards the corner at the foot end <NUM> to enable easy access and to minimise the risk of pumps and pipes restricting access to the patient or presenting a trip hazard for staff working around the patient.

With specific reference now to <FIG> and <FIG>, the mattress <NUM> has an array of baffles. The baffles are regions inside the perimeter <NUM> of the mattress <NUM> where the top sheet <NUM> and bottom sheet <NUM> are joined together. In this particular embodiment the top sheet <NUM> and bottom sheet <NUM> are joined together at the baffles by welding. By using the same bonding method as the perimeter <NUM>, the baffles and perimeter <NUM> can be formed advantageously in a single welding step. The baffles help to retain structure in the mattress <NUM> when inflated.

The mattress <NUM> includes different types of baffles. A set of upper body support baffles <NUM> are arranged over a region of the mattress <NUM> towards the head end <NUM>. The upper body support baffles <NUM> are arranged generally transversely across the mattress <NUM> and have a slightly concave shape. The concave shape helps to enhance the structural rigidity of the mattress <NUM> in the region towards the head end, making it harder to fold or bend the mattress <NUM> in this region when inflated. The upper body support baffles <NUM> are intended to support the torso of a patient in use.

In the embodiment shown in <FIG>, there are four upper body support baffles <NUM> which extend generally transversely and are longitudinally spaced apart. The upper body support baffles <NUM> are spaced apart from the head end <NUM> to define a pillow region <NUM> which is devoid of baffles. When inflated, the top sheet <NUM> in the pillow region <NUM> between the baffles <NUM> and the head end <NUM> will rise upwards above the baffles <NUM> to create an elevated pillow region <NUM> which provides additional head support for the patient.

In a central longitudinal region of the mattress, a set of hip joint baffles <NUM> is provided. In this particular embodiment the central longitudinal region corresponds to the central <NUM>% of the mattress length. The set of hip joint baffles <NUM> is an array of smaller baffles arranged closer together (compared with the support baffles <NUM>). In this particular embodiment, the set of hip joint baffles <NUM> has three rows of short transversely extending baffles, each row consisting of five substantially equally sized and spaced baffles. The three rows extend substantially perpendicular to the longitudinal axis X (i.e. substantially transversely). The hip joint baffles <NUM> extend almost to the perimeter <NUM>. When inflated, the hip joint baffles <NUM> makes the central longitudinal region less rigid in a transverse direction and the mattress <NUM> can consequently be bent or folded transversely in this region. The central longitudinal region corresponds approximately with the position of a patient's hip joint. The mattress <NUM> can therefore be bent or folded in this region when the patient is moved between a lying and a seated position (or vice versa).

A set of knee joint baffles <NUM> is provided in a knee joint region of the mattress <NUM> between the central longitudinal region and the foot end <NUM>. The set of knee joint baffles <NUM> is an array of smaller baffles arranged closer together (compared with the support baffles <NUM>). In this particular embodiment, the set of knee joint baffles <NUM> has two rows of short transversely extending baffles, each row consisting of five substantially equally sized and spaced baffles. The rows extend substantially perpendicular to the longitudinal axis X. The knee joint baffles <NUM> extend almost to the perimeter <NUM>. When inflated, the knee joint baffles <NUM> make the knee joint region less rigid in a transverse direction and the mattress <NUM> can consequently be bent or folded transversely in this region. The knee joint region corresponds approximately with the position of a patient's knees. The mattress <NUM> can therefore be bent or folded in this region when the patient is moved between a lying and a seated position (e.g. between a bed and a chair) or vice versa.

Between the hip joint baffles <NUM> and the knee joint baffles <NUM>, there is a set of thigh support baffles <NUM>. The thigh support baffles <NUM> are similar in size and shape to the upper body support baffles <NUM>. The thigh support baffles <NUM> are arranged generally transversely across the mattress <NUM> and have a slightly concave shape to enhance the structural rigidity of the mattress <NUM>. The thigh support baffles <NUM> are intended to support the thighs of a patient in use.

In the embodiment shown in <FIG>, there are two thigh support baffles <NUM> which extend generally transversely and are longitudinally spaced apart. The thigh support baffles <NUM> have a slightly concave shape, with the two concave edges of the two baffles <NUM> oriented away from each other.

Between the knee joint baffles <NUM> and the foot end <NUM>, a set of calf support baffles <NUM> is provided. The calf support baffles <NUM> are similar in size and shape to the upper body and thigh support baffles <NUM>, <NUM>. The calf support baffles <NUM> are arranged generally transversely across the mattress <NUM> and have a slightly concave shape to enhance the structural rigidity of the mattress <NUM>. The calf support baffles <NUM> are intended to support the calves of a patient in use. The calf support baffles <NUM> are spaced apart from the foot end <NUM> to define a foot support region <NUM> which is free from baffles. The valve <NUM> is positioned in the foot support region <NUM>.

The upper body support baffles <NUM>, thigh support baffles <NUM> and calf support baffles <NUM> do not extend to the perimeter <NUM> of the mattress, leaving an edge region <NUM> which is free from baffles. When inflated, the top sheet <NUM> in the edge region <NUM> will rise upwards above the baffles <NUM>, <NUM>, <NUM>. As best illustrated in <FIG>, this creates a low wall which partially surrounds the patient and reduces the risk of the patient rolling sideways off the mattress <NUM>.

In the embodiment shown in <FIG>, there are two calf support baffles <NUM> which extend generally transversely and are longitudinally spaced apart. The calf support baffle <NUM> positioned closest to the foot end <NUM> is slightly shorter in this particular embodiment to facilitate airflow throughout the cavity <NUM> from the valve <NUM> during inflation. The calf support baffles <NUM> have a slightly concave shape, with the two concave edges of the two baffles <NUM> oriented away from each other.

With reference now to <FIG>, an underside of the mattress <NUM> is shown. The bottom sheet <NUM> has a low-friction silicone coating <NUM> on the underside (i.e. outwards facing) surface. The low-friction silicone coating <NUM> is applied to the entire underside face of the bottom sheet <NUM>. In use, the silicone coating <NUM> reduces the friction as the inflated mattress is pulled across a substrate (for example a table, bed, trolley or floor) owing to the relatively low coefficient of friction of the silicone coating <NUM>.

The underside of the mattress <NUM> is provided with several grip pads. In this particular embodiment the mattress <NUM> has two shoulder grip pads <NUM>, an abdomen grip pad <NUM>, two calf grip pads <NUM> and two foot grip pads <NUM>. The grip pads are affixed to the bottom sheet <NUM> at the baffles. In particular, the shoulder grip pads <NUM> and the abdomen grip pad <NUM> are positioned on the upper body support baffles <NUM>, whereas the calf grip pads <NUM> and foot grip pads <NUM> are positioned on the calf support baffles <NUM>. The grip pads <NUM>, <NUM>, <NUM>, <NUM> are elongate and are arranged generally transversely.

The grip pads <NUM>, <NUM>, <NUM>, <NUM> are composed of neoprene. Neoprene has a relatively high coefficient of friction and the grip pads therefore help to anchor the mattress <NUM> when they are in contact with a substrate.

With reference now to <FIG>, a longitudinal cross-section of the mattress <NUM> in a region surrounding the lowermost upper body support baffle <NUM> (i.e. the upper body support baffle furthest from the head end <NUM>) is shown. The top sheet <NUM> and bottom sheet <NUM> together surround a cavity <NUM>. At the baffle <NUM>, the top and bottom sheets <NUM>, <NUM> are welded together. The abdomen grip pad <NUM> is provided on the bottom sheet <NUM> on the underside of the baffle <NUM>. The top sheet <NUM> has a waterproof coating <NUM> over an outwards facing surface.

In use, the mattress <NUM> will typically be placed on a substrate <NUM> such as a bed, table, trolley etc. When the mattress <NUM> is deflated as shown in <FIG>, the grip pad <NUM> will contact the surface of the substrate <NUM>. The relatively high coefficient of friction of the neoprene grip pad <NUM> helps to anchor the mattress <NUM> onto the substrate <NUM> and prevents the mattress <NUM> from being easily dragged across the substrate <NUM>. In addition to this, a contact area <NUM> of the bottom sheet <NUM> is in contact with the substrate <NUM> increases friction (despite the low friction coating <NUM>). This helps to ensure the mattress <NUM> remains in place and does not slide around underneath a patient when deflated. Consequently, the mattress <NUM> can be safely left underneath a patient during a procedure or examination. This saves the time taken to remove the mattress <NUM> after the patient has been transferred to an operating or examination table, and to replace it after the procedure.

When the mattress <NUM> is inflated (as shown in <FIG>) the cavity <NUM> either side of the baffle <NUM> expands, lifting the baffle <NUM> up and away from the substrate <NUM>. The grip pad <NUM> is also lifted away from the substrate <NUM>. In addition to this, the contact area <NUM> of the bottom sheet <NUM> is significantly reduced compared to when the mattress <NUM> is deflated. These two factors together significantly reduce the friction resistance, enabling the mattress <NUM> and patient to be dragged across the substrate <NUM> without excessive effort.

With reference now to <FIG> and <FIG>, another mattress <NUM> is shown. The mattress <NUM> is very similar to the mattress <NUM> and is of a similar size and shape with the same general construction and the same arrangement of handles <NUM>, baffles, grip pads and valve <NUM>. However the mattress <NUM> is additionally provided with a set of strap loops <NUM> around the perimeter <NUM> on either side of a torso region adjacent to the hip joint baffles <NUM>. The strap loops <NUM> and handles <NUM> are formed integrally in the perimeter <NUM> of the mattress <NUM> as the top and bottom sheets <NUM>, <NUM> are welded together. As shown in <FIG>, a restraining strap <NUM> can be fed through the loops <NUM>. The restraining strap <NUM> can be used as required to restrain and/or secure the patient during transport to reduce the risk of the patient rolling off or falling from the mattress <NUM>.

Referring again to <FIG>, a heat map is superimposed onto the bottom sheet <NUM> for illustration. This heat map shows the high mass points of a typical adult patient when lying on the mattress <NUM>. The grip pads <NUM>, <NUM>, <NUM>, <NUM> are positioned within baffles at or close to the high mass points. For example the shoulder grip pads <NUM> are positioned around high mass points around the shoulders. The calf grip pads <NUM> are positioned around high mass points around the calves. By strategically positioning the grip pads at or near points where the mass of the patient on the mattress <NUM> is highest, the grip pads are more effective at anchoring the mattress <NUM> to the substrate <NUM> when the mattress <NUM> is deflated.

The mattresses <NUM> and <NUM> were formed by taking two similarly sized thermoplastic polyurethane sheets, applying a silicone coating <NUM> to one side of a first sheet to form the bottom sheet <NUM>, applying a waterproof coating <NUM> to one side of the second sheet to form a top sheet <NUM>, and implanting a valve <NUM> into the top sheet <NUM> towards a foot end corner. The top sheet <NUM> was then laid over the bottom sheet <NUM> with the waterproof coating <NUM> and silicone coating <NUM> facing outwards. The two sheets were then cut to shape, and then welded together around a perimeter <NUM> and at the baffles by high frequency welding to form the cavity <NUM>, handles <NUM> and strap loops <NUM> (for the mattress <NUM>). By welding the top and bottom sheets <NUM>, <NUM> together around the perimeter <NUM> and at the baffles in a single step, production of the mattress <NUM> is simplified, rapid and low cost and requires no stitching.

In use, mattress <NUM> (in a deflated configuration) is placed on a substrate <NUM> such as a bed, table, trolley etc. A patient <NUM> then lays or is assisted to lie on the top sheet <NUM> with their head towards the head end <NUM> and their feet towards the foot end <NUM>. To move the patient <NUM>, a pump is attached to the valve <NUM> and air is forced into the cavity <NUM> to inflate the mattress <NUM>. This raises the top sheet <NUM> away from the bottom sheet <NUM> (except at the baffles), lifting the patient <NUM> away from the substrate <NUM>. At the same time, the grip pads are lifted out of contact with the substrate <NUM> and the contact area <NUM> of the bottom sheet <NUM> on the substrate <NUM> is reduced. This decreases friction between the mattress <NUM> and the substrate <NUM>. Staff can then use the handles <NUM> to pull or push the mattress <NUM> across the substrate <NUM> or between the substrate <NUM> and another surface. When the patient <NUM> has been repositioned, the valve <NUM> is opened to allow air to escape from the cavity <NUM> and the mattress <NUM> is deflated. This brings the grip pads into contact with the substrate <NUM> and increases the contact area <NUM> of the bottom sheet <NUM> on the substrate <NUM>. This anchors the mattress <NUM> to the substrate <NUM>. The patient <NUM> can then safely leave the mattress <NUM> or be assisted to leave the mattress <NUM>. Alternatively a procedure can be performed on the patient <NUM> whilst they remain on the deflated mattress <NUM>.

With reference now to <FIG>, another transfer mattress <NUM> is shown. The transfer mattress <NUM> is elongate and is generally rectangular in shape with a head end <NUM>, a foot end <NUM> and a perimeter <NUM>. The mattress <NUM> has a size sufficient for the entire body of an adult patient in a supine position to be positioned on the mattress <NUM>. In this particular embodiment the mattress has a maximum inflated width of <NUM> and a length of <NUM>.

As best illustrated in <FIG>, the top sheet <NUM> and bottom sheet <NUM> are welded together around the perimeter <NUM> of the mattress <NUM> to define an inflatable cavity <NUM> (not visible) between the top and bottom sheets <NUM>, <NUM>. This bonding method simplifies the manufacturing process and reduces the risk of failure or leaks around the perimeter <NUM>.

With reference now to <FIG> and <FIG>, a handle strip <NUM> is positioned along each longitudinal edge of the mattress <NUM>. The handle strips <NUM> are composed of a webbing material to provide extra strength. The handle strips <NUM> are stitched to the top sheet <NUM> at the perimeter <NUM> at discrete, longitudinally spaced points <NUM> to define multiple grippable handle portions along each longitudinal edge of the mattress <NUM> as shown in <FIG>.

With reference now to <FIG>, <FIG> and <FIG>, the mattress <NUM> has an array of baffles <NUM>. The baffles <NUM> are regions inside the perimeter <NUM> of the mattress <NUM> where the top sheet <NUM> and bottom sheet <NUM> are joined together, in this particular embodiment by welding. The baffles <NUM> help to retain structure in the mattress <NUM> when inflated. Unlike the mattress <NUM> of <FIG>, the baffles <NUM> of the mattress <NUM> extend generally longitudinally, with some transverse extend towards the head end <NUM> in a pillow region <NUM>. The baffles <NUM> are configured such that the cavity <NUM> is not partitioned into more than one plenum chamber, i.e. the entire cavity can be inflated and deflated via the valve <NUM>.

With reference now to <FIG> and <FIG>, a cover sheet <NUM> is positioned underneath and attached to the bottom sheet <NUM>. The cover sheet <NUM> is composed of a low-friction silicone material. The cover sheet is stitched to the bottom sheet <NUM> around the perimeter <NUM> and along the longitudinal baffles <NUM>. In use, the low-friction silicone material of the cover sheet <NUM> reduces the friction as the inflated mattress is pulled across a substrate (for example a table, bed, trolley or floor) owing to the relatively low coefficient of friction of silicone.

The underside of the mattress <NUM> is provided with several neoprene grip pads <NUM>, <NUM>, <NUM>. The grip pads are positioned within the longitudinal baffles <NUM> roughly corresponding to the position of a patient's shoulders, abdomen and calves. In this particular embodiment the mattress <NUM> has four shoulder grip pads <NUM>, four abdomen grip pads <NUM> and three calf grip pads <NUM>. The grip pads are affixed to the cover sheet <NUM> along the baffles <NUM>. The grip pads <NUM>, <NUM>, <NUM> are elongate and are arranged generally longitudinally. The grip pads <NUM>, <NUM>, <NUM> function in essentially the same manner as the grip pads <NUM>, <NUM>, <NUM>.

The mattress <NUM> was formed by taking two similarly sized thermoplastic polyurethane sheets and implanting a valve <NUM> into one of the sheets towards a foot end corner to form a top sheet <NUM>. The top sheet <NUM> was then laid over the other sheet (bottom sheet <NUM>), the two sheets were cut to shape, and then welded together around a perimeter <NUM> and at the baffles <NUM> by high frequency welding to form a cavity <NUM>. A silicone cover sheet <NUM> was then attached to the bottom sheet <NUM> by stitching around the perimeter <NUM> and at the baffles <NUM>. Neoprene grip pads <NUM>, <NUM>, <NUM> were then affixed at the baffles <NUM> to the cover sheet <NUM>. Handle strips <NUM> were then stitched to the perimeter <NUM> at multiple points <NUM> along each longitudinal edge of the mattress <NUM>.

Claim 1:
An inflatable mattress (<NUM>) for patient transfer comprising:
an elongate top sheet (<NUM>) having a head end (<NUM>), a foot end (<NUM>) and a longitudinal axis extending therebetween;
an elongate bottom sheet (<NUM>) having substantially the same size as the top sheet (<NUM>) and positioned adjacent to the top sheet (<NUM>), wherein the top and bottom sheets (<NUM>, <NUM>) are joined around their perimeter (<NUM>) to define a cavity (<NUM>) between the top and bottom sheets (<NUM>, <NUM>); and
a valve (<NUM>) in fluid communication with the cavity (<NUM>), wherein the valve (<NUM>) includes a port on an external surface of the mattress (<NUM>) to enable the cavity (<NUM>) to be inflated or deflated,
wherein the inflatable mattress (<NUM>) comprises a low friction material (<NUM>) provided on at least a portion of an outwards facing surface of the bottom sheet (<NUM>), or optionally on a cover sheet (<NUM>) attached to and covering at least a portion of the bottom sheet (<NUM>), wherein the top and bottom sheets (<NUM>, <NUM>) are joined within the cavity (<NUM>) at one or more baffles (<NUM>); characterised in that the mattress (<NUM>) further comprises one or more grip pads (<NUM>, <NUM>, <NUM>, <NUM>) composed of a high-friction material disposed on the outwards facing surface of the bottom sheet (<NUM>) or, where present, the cover sheet (<NUM>);
wherein the grip pads (<NUM>, <NUM>, <NUM>, <NUM>) are positioned adjacent or on baffles (<NUM>) such that, in use, when the mattress (<NUM>) is deflated, the grip pads (<NUM>, <NUM>, <NUM>, <NUM>) will contact a substrate, thus increasing friction between the mattress (<NUM>) and the substrate, and when the mattress (<NUM>) is inflated, the grip pads (<NUM>, <NUM>, <NUM>, <NUM>) will be raised away from and will no longer contact the substrate.