Patient positioning apparatus and mattress

Abstract

A patient positioning apparatus for use with a mattress has a first lateral tilt bladder and a third lateral tilt bladder underlying a first side of the mattress, and a second lateral tilt bladder and a fourth lateral tilt bladder underlying a second side of the mattress. The tilt bladders are inflatable to alter the position of a patient lying on the mattress, and inflation and/or deflation of the lateral tilt bladders is controllable by a controller. A first check valve allows fluid communication in one direction from the third lateral tilt bladder to the first lateral tilt bladder, and a second check valve allows fluid communication in one direction from the fourth lateral tilt bladder to the second lateral tilt bladder.

Claims

1. A patient positioning apparatus for use with a mattress, the patient positioning apparatus comprising: a first lateral tilt bladder and a third lateral tilt bladder configured to underlie a first side of the mattress, and a second lateral tilt bladder and a fourth lateral tilt bladder configured to underlie a second side of the mattress, in which the tilt bladders are inflatable to alter a position of a patient lying on the mattress; in which a pair of sheets are welded together to form the first, second, third, and fourth lateral tilt bladders between the sheets; in which inflation and/or deflation of the lateral tilt bladders is controllable by a controller; in which the first lateral tilt bladder is configured to tilt the patient's sternum towards the second side of the mattress when inflated, the second lateral tilt bladder is configured to tilt the patient's sternum towards the first side of the mattress when inflated, the third lateral tilt bladder is configured to tilt the patient's pelvis towards the second side of the mattress when inflated, and the fourth lateral tilt bladder is configured to tilt the patient's pelvis towards the first side of the mattress when inflated, in which a first check valve is configured to allow fluid communication in one direction from the third lateral tilt bladder to the first lateral tilt bladder, and a second check valve is configured to allow fluid communication in one direction from the fourth lateral tilt bladder to the second lateral tilt bladder, in which each lateral tilt bladder is in fluid communication with a separate inflation port, and in which the first lateral tilt bladder is inflatable without inflating the third lateral tilt bladder, and the second lateral tilt bladder is inflatable without inflating the fourth lateral tilt bladder, and in which the first and third lateral tilt bladders and the second and fourth lateral tilt bladders are separated by openings formed by cuts through the pair of sheets and the cuts being surrounded by lines of radio frequency (RF) welding.

2. A patient positioning apparatus according to claim 1, in which the first and second lateral tilt bladders extend in a longitudinal direction from a waist portion towards a head end of the patient positioning apparatus and have a length of greater than or equal to 690 mm, or 700 mm, or 710 mm, or 720 mm, or 750 mm, or 775 mm, or 800 mm, or 825 mm, or 850 mm, and less than or equal to 875 mm, or 900 mm, or 925 mm, or 950 mm.

3. A patient positioning apparatus according to claim 1, in which the third and fourth lateral tilt bladders are positioned between a waist portion and a foot end of the apparatus, and have a length of greater than or equal to 400 mm, or 425 mm, or 450 mm, or 480 mm, and less than or equal to 500 mm, or 525 mm, or 550 mm.

4. A patient positioning apparatus according to claim 1, further comprising a first pressure sensor configured to sense a pressure in the first lateral tilt bladder, and a second pressure sensor configured to sense a pressure in the second lateral tilt bladder, in which the controller is responsive to the first and second pressure sensors for controlling the inflation and/or deflation of the lateral tilt bladders.

5. A patient positioning apparatus according to claim 1, in which the controller is programmed to control the apparatus in a lateral pressure redistribution (LPR) mode, in which the first lateral tilt bladder is inflated to a predetermined LPR pressure before being deflated, and either the first or second lateral tilt bladder is then inflated to a predetermined LPR pressure before being deflated, so that the patient's sternum is tilted repeatedly.

6. A patient positioning apparatus according to claim 1, in which the controller is programmed to control the apparatus in a Continuous Lateral Rotation Therapy (CLRT) mode in which the first and third lateral tilt bladders are inflated to a predetermined CLRT pressure, following which the first and third bladders are deflated and the second and fourth bladders are inflated to the predetermined CLRT pressure, in which an inflation cycle is repeated to continuously rotate the patient on the mattress.

7. A patient positioning apparatus according to claim 1, in which the first and third lateral tilt bladders, and the second and fourth tilt bladders, respectively, are separated by a longitudinal distance of greater than or equal to 50 mm, or 60 mm, and less than or equal to 80 mm or 100 mm.

8. A patient positioning apparatus according to claim 1, in which the first and third lateral tilt bladders, and the second and fourth tilt bladders, respectively, are separated by openings formed through the apparatus.

9. A patient positioning apparatus according to claim 1, in which the inflation ports are configured to be connectable directly to the outlets of an inflation manifold.

10. A patient positioning apparatus according to claim 1, in which the inflation ports are positioned at a foot-end of the patient positioning apparatus and connected to their respective first, second, third, and fourth lateral tilt bladders by welded conduits.

11. A mattress, comprising a mattress layer and the patient positioning apparatus according to claim 1, in which the patient positioning apparatus is positioned beneath the mattress layer, so that inflation of the first, second, third, and fourth lateral tilt bladders moves the mattress layer to alter a lateral position of a patient lying on the mattress layer.

12. A mattress according to claim 11, in which a waist portion of the patient positioning apparatus is positioned beneath a waist portion of the mattress layer so that the first lateral tilt bladder and the third lateral tilt bladder underlie a first side of the mattress, and the second lateral tilt bladder and the fourth lateral tilt bladder underlie a second side of the mattress, and a waist portion of the patient positioning apparatus is positioned beneath a waist portion of the mattress.

13. A mattress according to claim 11, in which the mattress layer is a mattress surface layer, or an overlay, or an upper air mattress layer.

14. A mattress system comprising a mattress according to claim 11, a pump, and an inflation manifold connectable to the first, second, third, and fourth lateral tilt bladders, in which the pump is controllable by the controller to pump fluid through the inflation manifold to inflate or deflate the first, second, third, and fourth lateral tilt bladders.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a schematic illustration of a patient positioning apparatus, pump and controller according to a first embodiment of an aspect of the invention;

(3) FIG. 2 shows a schematic illustration of a patient positioning apparatus, pump and controller according to a second embodiment of an aspect of the invention;

(4) FIG. 3 shows a schematic plan view of a patient above a patient positioning apparatus according to an aspect of the invention;

(5) FIG. 4 shows a schematic perspective view of a patient positioning apparatus and inflation manifold according to an embodiment of an aspect of the invention;

(6) FIG. 5 shows an exploded view of a multi-layer mattress assembly according to an aspect of the invention.

DETAILED DESCRIPTION OF DRAWINGS

(7) FIG. 1 shows a schematic plan view of a first embodiment of a patient positioning apparatus 100 connected to a pump 110 and a controller 120.

(8) The patient positioning apparatus comprises a first inflatable bladder 10 positioned next to an identical second inflatable bladder 12. The first and second inflatable bladders 10, 12 are oblong in shape with rounded corners, and have a length of 850 mm. A waist end 11 of the first and second inflatable bladders is located at a waist portion of the apparatus, and a head end 13 of the bladders is located adjacent a head end of the apparatus.

(9) A third inflatable bladder 14 is positioned below the first inflatable bladder 10, and a fourth inflatable bladder 16 is positioned below the first inflatable bladder 12. Each of the inflatable bladders is connected to a separate inlet valve 18 by pneumatic tubing. The four inlet valves 18 are connected to the pump 110 via an inflation manifold (not shown). Each of the inflatable bladders is also connected to a separate pressure sensor 22 and an outlet valve (not shown).

(10) The controller 120 comprises of an electronic circuit board 24 which is connected to receive measurements from the pressure sensors 22. A user may interact with the controller, for example to input information or select a control mode, via a graphic user interface 24. In this exemplary embodiment a mattress sensor 26 is connected to the controller to provide the controller with information about patient immersion in the mattress. The controller is electrically connected to the pump 110, the inlet valves 18 and the outlet valves so that the controller can control the operation of the pump and the individual valves.

(11) In use, the four inflatable bladders 10, 12, 14, 16 are positioned on a bed frame beneath a mattress layer (not shown). The bladders are configured to align with the mattress layer so that the waist ends 11 of the first and second inflatable bladders 10, 12 are positioned under a waist portion of the mattress, and the third and fourth inflatable bladders 14, 16 are positioned under a middle section of the mattress, such that the first and third bladders underlie one side of the mattress layer and the second and fourth bladders underlie the other side of the mattress layer. When a patient lies on the mattress in a supine position (on their back, facing upwards), the patient's chest and upper body is positioned directly above the first and second inflatable bladders, while their pelvis is positioned above the third and fourth inflatable bladders.

(12) The controller 120 is programmed to control the inflation and deflation of the four bladders 10, 12, 14, 16 according to a control mode selected by a user on the graphic user interface 24. Different control modes require one or more of the inflatable bladders to be inflated for a certain time, and to a certain pressure, in a predetermined pattern.

(13) In order to inflate a selected inflatable bladder, the controller activates a power supply to the pump 110, and opens the corresponding inlet valve 18 so that the pump drives air through the valve and into the inflatable bladder. As the bladder inflates, the pressure sensor 22 corresponding to that bladder measures the air pressure inside the bladder, and communicates that pressure to the controller 120. When the pressure in the bladder has reached a predetermined level, the controller closes the valve 18 and deactivates the pump 110.

(14) Inflation of one or more of the bladders causes the mattress overlay, and the patient on the mattress overlay, to tilt laterally away from the inflated bladder. So by inflating bladders in sequence, the patient may be rotated in a lateral plane as desired.

(15) In particular, inflation of the first lateral tilt bladder tilts the patient's sternum towards one side of the mattress, while inflation of the second lateral tilt bladder is configured to tilt the patient's sternum towards the other side of the mattress. Inflation of the third lateral tilt bladder tilts the patient's pelvis towards one side of the mattress, while inflation of the fourth lateral tilt bladder tilts the patient's pelvis towards the other side of the mattress.

(16) In order to deflate the bladder, the controller opens the corresponding outlet valve.

(17) The controller can operate the apparatus 100 to perform a variety of patient positioning protocols by inflating and deflating the bladders as appropriate for the selected control mode.

(18) The 850 mm length of the first and second inflatable bladders 10, 12 advantageously means that these bladders extend beneath the head and chest of a patient on the mattress overlay, but do not extend as far as the patient's pelvis. This means that, during positioning protocols for which only the patient's upper body should be tilted, the patient's pelvis is not tilted by the inflated bladders. This advantageously avoids loading pressure from the patient's weight onto the patient's sacrum when it is only necessary to rotate the patient's chest. This may advantageously help to reduce the occurrence of pressure sores, by reducing unnecessary pressure on the sacrum.

(19) An alternative embodiment of a patient positioning apparatus 200 is shown schematically in FIG. 2.

(20) The apparatus 200 consists of the same components as those of the first embodiment of the apparatus 100, with the difference that the third and fourth inflatable bladders 14, 16 are not connected to their own pressure sensors 22. Instead, the third inflatable bladder 14 is in fluid communication with the first inflatable bladder 10 via a first check valve 28, and the fourth inflatable bladder 16 is in fluid communication with the second inflatable bladder 12 via a second check valve 30. The apparatus comprises only two pressure sensors 22, which are connected to the first and second inflatable bladders respectively.

(21) The first check valve 28 is arranged to allow fluid to flow only in one direction from the third inflatable bladder 14 to the first inflatable bladder 10. Fluid flow from the first bladder to the third bladder is prevented by the check valve. In this configuration, fluid flows through the check valve from the third to the first bladder when the pressure in the third inflatable bladder is higher than the pressure in the first inflatable bladder. Likewise, the second check valve 30 is arranged to allow fluid to flow only from the fourth inflatable bladder 16 to the second inflatable bladder 12, and to prevent flow in the opposite direction.

(22) The presence of the check valves means that the third and fourth inflatable bladders cannot be inflated without at least partial inflation of the first and second bladders, as fluid will flow through the check valves as a result of the pressure difference across the valves.

(23) This solution is different to the approach of providing independently inflatable bladders, and slightly restricts the functionality of the apparatus 200 as the third and/or fourth bladders cannot be inflated on their own. The inventors have found, however, that this arrangement allows the apparatus 200 to perform a variety of positioning functions and protocols, while advantageously providing a simplified device. The check valves also advantageously ensure that in CLRT mode or turn assist mode, when the third and first (or fourth and second) bladders are being inflated simultaneously and air is being delivered to both bladders at the same flow rate, the check valve balances the pressure between bladders so that both bladders inflate at the same relative rate even though the volume of the third bladder is smaller than the volume of the first bladder. This means that the patient's pelvis and torso are tilted at the same angle as the bladders inflate.

(24) FIG. 3 illustrates the position of a patient on a mattress 300 above the bladders of a patient positioning apparatus. FIG. 3 shows the positions of the first, second, third and fourth lateral tilt bladders 10, 12, 14, 16 relative to the patient and the mattress 300. The patient positioning apparatus of FIG. 3 may be a patient positioning apparatus 100, 200 according to either of the embodiments shown in FIGS. 1 and 2.

(25) FIG. 3 shows two alternative sizes of the first bladder 10A, 10B and second bladder 12A, 12B to illustrate preferred positions of differently sized bladders relative to a mattress, and relative to a patient.

(26) In FIG. 3, first and second bladders 10A, 12A have a length of 750 mm. The waist end 11 of the first and second inflatable bladders 10A, 12A is located at a waist portion 400 of the apparatus, beneath a waist portion of the mattress. The waist portion 400 extends laterally across the apparatus and underlies the waist of the patient positioned on top of the mattress. As the first and second bladders 10A, 12A have a length of 750 mm, the head end 13A of the bladders 10A, 12A is located between the waist portion 400 and the head end 450 of the mattress, a distance of 750 mm from the waist portion. This leaves a separation of approximately 225 mm between the head end 13A of the bladders and the head end 450 of the mattress 300.

(27) The proportion of the patient overlying the first and second bladders 10A, 12A depends on the height of the patient. In the embodiment illustrated in FIG. 3, the first and second bladders 10A, 12A extend under the patient's upper body from the waist portion to a position approximately underneath the top of the patient's head.

(28) FIG. 3 also shows an alternative embodiment of the first and second bladders 10B, 12B with a length of 950 mm. The 750 mm-bladder embodiment 10A, 12A and the 950 mm-bladder embodiment 10B, 12B are shown overlaid upon one another for the purposes of comparative illustration in FIG. 3.

(29) First and second bladders 10B, 12B have a length of 950 mm. Similarly to the 750 mm bladders, the waist end 11 of the 950 mm bladders is located at a waist portion 400 of the apparatus. The head end 13B of the bladders 10B, 12B is located between the waist portion 400 and the head end 450 of the mattress, a distance of 950 mm from the waist portion. In this embodiment, the 950 mm bladders extend almost to the head end 450 of the mattress 300. This leaves a separation of approximately 25 mm between the head end 13B of the bladders and the head end 450 of the mattress 300.

(30) In this embodiment the 950 mm bladders 10B, 12B may advantageously extend beneath the neck and head of even the tallest patients. This may be preferable, for example, where the apparatus is to be used for sleep apnea treatment.

(31) As the first and second bladders extend from the same position at the waist portion 400, the position of the bladders relative to the torso and sacrum of the patient may advantageously be maintained regardless of bladder length.

(32) The mattress 300 may comprise some locating means (not shown) to ensure that the patient adopts the correct position, with their waist positioned above the waist portion 400 of the apparatus.

(33) In a particularly preferred embodiment, the first and second bladders 10A, 12A have a length of 721 mm. The waist end 11 of the first and second inflatable bladders 10A, 12A is located at a waist portion 400 of the apparatus, beneath a waist portion of the mattress. The waist portion 400 extends laterally across the apparatus and underlies the waist of the patient positioned on top of the mattress. As the first and second bladders 10A, 12A have a length of 721 mm, the head end 13A of the bladders 10A, 12A is located between the waist portion 400 and the head end 450 of the mattress, a distance of 721 mm from the waist portion. This leaves a separation of approximately 254 mm between the head end 13A of the bladders and the head end 450 of the mattress 300.

(34) FIG. 4 shows a perspective view of the patient support apparatus 200 connected to a combined pump and inflation manifold 250, which contains four inlet valves (not shown).

(35) The apparatus 200 is formed from two polyurethane (PU) fabric coated sheets, welded together to form first, second, third and fourth 10, 12, 14, 16 inflatable bladders therebetween. The apparatus is generally flat when the bladders are in a deflated state, and is generally oblong in shape, with a head-end 32 of the apparatus connected to a foot-end 34 by two sides 36.

(36) The first inflatable bladder 10 and the second inflatable bladder 12 are generally oblong in shape, and are positioned symmetrically on first and second sides of the apparatus, so that longitudinal axes of the bladders are parallel with the sides 36 of the apparatus. The first and second bladders 10, 12 are positioned to extend parallel with the sides 36 from the head-end 32 of the apparatus over approximately half of the length of the apparatus. In the embodiment shown, the first and second bladders have a length of 850 mm, measured in a longitudinal direction parallel to the sides of the apparatus 200, and a width of 450 mm, measured in a transverse direction parallel to the head-end edge 32 of the apparatus.

(37) The third inflatable bladder 14 is positioned between the first bladder 10 and the foot-end 34 of the apparatus, and is generally oblong in shape. The fourth inflatable bladder 16 is positioned between the second bladder 12 and the foot-end 34 of the apparatus, and is formed as a mirror image of the third bladder. In the embodiment shown, the third and fourth inflatable bladders have a length of 450 mm and a width of 400 mm.

(38) First and second check valves 28, 30 extend between the first and third inflatable bladders, and the second and fourth inflatable bladders, respectively.

(39) The first and third bladders, and the second and fourth bladders, are respectively separated by a longitudinal distance of approximately 60 mm. Adjacent bladders are additionally separated by openings 38, formed by cuts through the apparatus and surrounded by lines of RF welding. The openings 38 extend in a transverse direction across the waist portion of the apparatus. Separate RF-welded conduits 40 extend from each inflatable bladder to inflation ports 42 positioned at the foot-end 34 of the apparatus. The inflation ports 42 are formed from cyclindrical plastic inserts, which are welded directly into the conduits in the apparatus. The inserts are sized to receive and connect directly to outlets on the inflation manifold 250.

(40) The dimensions of the apparatus 200 are such that it may be positioned beneath a mattress overlay, and optionally other components of a mattress, so that the bladders are positioned under specific portions of the mattress. The width of the apparatus 200 is approximately the same as the width of the mattress overlay, while the length of the apparatus is approximately two-thirds of the length of the mattress overlay. By positioning the head-end of the apparatus in line with the head-end of the mattress overlay, these dimensions mean that, when an adult patient is lying on the mattress, the first and second inflatable bladders 10, 12 are aligned beneath the sides of the patient's head and chest, while the third and fourth inflatable bladders 14, 16 are positioned beneath the sides of the patient's pelvis.

(41) In use, a caregiver may select one of the control modes programmed into the controller 120, or optionally the caregiver may instruct the controller to perform a bespoke positioning protocol.

(42) Once a control mode has been selected, the controller 120 automatically controls the pump and the inlet valves in the inflation manifold, so that the bladders are inflated to a desired pressure. In certain control modes, the bladders may be inflated and deflated at different times, and in different orders, in order to automatically move or reposition the patient at predetermined time intervals.

(43) The controller 120 may be programmed to operate in one of the following control modes: lateral pressure redistribution (LPR); sleep apnea; continuous lateral rotation therapy (CLRT); or turn assist.

(44) FIG. 5 shows an exploded view of the patient positioning apparatus 200 in position in a mattress assembly 300. Unlike the devices of the prior art, the patient positioning apparatus is placed low down the mattress assembly, below other layers of the assembly.

(45) This means that inflation of the bladders tilts the overlying layers of the mattress in order to reposition the patient, so that the cushioning of the mattress overlay and other mattress layers is retained between the patient and the inflated bladders at all times. This may advantageously be more comfortable for the patient than other devices in which the bladders are located at the top of the mattress assembly in order to protrude out of the upper surface when inflated.

(46) It will be appreciated that the above described embodiments are exemplary embodiments of the invention only. It will also be appreciated that features described above in relation to one embodiment of the invention may also be applied to other embodiments of the invention.

Preferred Aspects

(47) Preferred aspects of the invention are defined by way of example in the following numbered clauses:

(48) Clause 1. A patient positioning apparatus for use with a mattress, the patient positioning apparatus comprising:

(49) a first lateral tilt bladder configured to underlie a first side of the mattress, and a second lateral tilt bladder configured to underlie a second side of the mattress, in which the tilt bladders are inflatable to alter the position of a patient lying on the mattress;

(50) in which inflation and/or deflation of the lateral tilt bladders is controllable by a controller; and

(51) in which the first and second lateral tilt bladders extend in a longitudinal direction from a waist portion towards a head end of the patient positioning apparatus and have a length of between 690 mm and 950 mm, such that the first lateral tilt bladder is configured to tilt the patient's sternum towards the second side of the mattress when inflated, and the second lateral tilt bladder is configured to tilt the patient's sternum towards the first side of the mattress when inflated.

(52) Clause 2. A patient positioning apparatus for use with a mattress, the patient positioning apparatus comprising:

(53) a first lateral tilt bladder configured to underlie a first side of the mattress, and a second lateral tilt bladder configured to underlie a second side of the mattress, in which the tilt bladders are inflatable to alter the position of a patient lying on the mattress; in which inflation and/or deflation of the lateral tilt bladders is controllable by a controller; and

(54) in which the first and second lateral tilt bladders extend in a longitudinal direction from a waist portion towards a head end of the patient positioning apparatus and have a length of between 750 mm and 950 mm, such that the first lateral tilt bladder is configured to tilt the patient's sternum towards the second side of the mattress when inflated, and the second lateral tilt bladder is configured to tilt the patient's sternum towards the first side of the mattress when inflated.

(55) Clause 3. A patient positioning apparatus according to clause 1 or 2, in which the first and second lateral tilt bladders have a length of greater than or equal to 775 mm, or 800 mm, or 825 mm, or 850 mm, and less than or equal to 875 mm, or 900 mm, or 925 mm.

(56) Clause 4. A patient positioning apparatus according to clause 1, 2 or 3, comprising a first pressure sensor configured to sense a pressure in the first lateral tilt bladder, and a second pressure sensor configured to sense a pressure in the second lateral tilt bladder, in which the controller is responsive to the first and second pressure sensors for controlling the inflation and/or deflation of the lateral tilt bladders.

(57) Clause 5. A patient positioning apparatus according to any preceding clause, additionally comprising a third lateral tilt bladder configured to underlie the first side of the mattress, and a fourth lateral tilt bladder configured to underlie the second side of the mattress, such that the third lateral tilt bladder is configured to tilt the patient's pelvis towards the second side of the mattress when inflated, and the fourth lateral tilt bladder is configured to tilt the patient's pelvis towards the first side of the mattress when inflated.

(58) Clause 6. A patient positioning apparatus according to clause 5 in which the third and fourth lateral tilt bladders have a length of greater than or equal to 400 mm, or 425 mm, or 450 mm, or 480 mm, and less than or equal to 500 mm, or 525 mm, or 550 mm.

(59) Clause 7. A patient positioning apparatus according to clause 5 or 6, in which a first check valve is configured to allow fluid communication in one direction from the third lateral tilt bladder to the first lateral tilt bladder, and/or a second check valve is configured to allow fluid communication in one direction from the fourth lateral tilt bladder to the second lateral tilt bladder.

(60) Clause 8. A patient positioning apparatus according to clause 5 or 6, comprising a third pressure sensor configured to sense a pressure in the third lateral tilt bladder, and a fourth pressure sensor configured to sense a pressure in the fourth lateral tilt bladder, in which the controller is responsive to the third and fourth pressure sensors for controlling the inflation and/or deflation of the third and fourth lateral tilt bladders.

(61) Clause 9. A patient positioning apparatus according to any preceding clause, in which the controller is programmed to control the apparatus in a lateral pressure redistribution (LPR) mode, in which the first lateral tilt bladder is inflated to a predetermined LPR pressure before being deflated, and either the first or second lateral tilt bladder is then inflated to a predetermined LPR pressure before being deflated, so that the patient's sternum is tilted repeatedly.

(62) Clause 10. A patient positioning apparatus according to any of clauses 5 to 9, in which the controller is programmed to control the apparatus in a Continuous Lateral Rotation Therapy (CLRT) mode in which the first and third lateral tilt bladders are inflated to a predetermined CLRT pressure, following which the first and third bladders are deflated and the second and fourth bladders are inflated to the predetermined CLRT pressure, in which the inflation cycle is repeated to continuously rotate the patient on the mattress.

(63) Clause 11. A patient positioning apparatus according to clause 10, in which the first lateral tilt bladder is inflated to a higher pressure than the third bladder, and the second lateral tilt bladder is inflated to a higher pressure than the fourth bladder, so that the patient's torso is rotated to a greater angle than their pelvis during the CLRT cycle.

(64) Clause 12. A patient positioning apparatus according to any of clauses 5 to 11, in which the first and third lateral tilt bladders, and the second and fourth tilt bladders, respectively, are separated by a longitudinal distance of greater than or equal to 50 mm, or 60 mm, and less than or equal to 80 mm or 100 mm.

(65) Clause 13. A patient positioning apparatus according to any of clauses 5 to 12, in which the first and third lateral tilt bladders, and the second and fourth tilt bladders, respectively, are separated by openings formed through the apparatus.

(66) Clause 14. A patient positioning apparatus according to any preceding clause, in which the apparatus comprises a plurality of inflation ports, each of which is in fluid communication with a respective lateral tilt bladder, and in which the inflation ports are configured to be connectable directly to the outlets of an inflation manifold.

(67) Clause 15. A patient positioning apparatus according to clause 14, in which the inflation ports are positioned at the foot-end of the patient positioning apparatus and connected to their respective bladders by welded conduits.

(68) Clause 16. A mattress, comprising a mattress layer and a patient positioning apparatus according to any preceding clause, in which the patient positioning apparatus is positioned beneath the mattress layer, so that inflation of the lateral tilt bladders moves the mattress layer to alter the lateral position of a patient lying on the mattress layer.