Body Compression System

Abstract

A body compression system for use in applying compression to a patient positioned on a support surface includes an overlay and a gas supply system. The overlay includes a flexible sheet material disposed in at least two layers and defining an interior region therebetween, an inlet orifice opening into the interior region, and a restraint that defines and restrains the edges of the flexible sheet material in use. The layers are repositionable relative to each other so that the sheet material can assume a contracted state in which the interior region volume is minimized. In use of the body compression system, the flexible sheet material of the overlay is draped over the patient and restrained relative to the support surface by the restraint, and the gas supply system is operable to deliver gas to increase the interior region volume from the contracted state and establish increased pressure in the interior region, thereby compressing the patient between the rear layer of the overlay and the support surface.

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present invention relates to a body compression system, and more particularly to a system for use in applying compression to a patient for management and / or assistance in medical intervention or investigation. [Background technology]

[0002] background There are instances where it is desirable to apply compression to control and / or assist in medical intervention or investigation. Compression may be advantageous to control internal fluid pressure or distribution within the patient's body. Additionally, compression may be advantageous to partially immobilize the patient to limit discomfort and / or prevent the aggravation of an existing condition.

[0003] As an example of managing the blood pressure of a human or animal (hereinafter referred to as a "patient"), it may be desirable to increase the patient's venous blood pressure in response to an adverse symptom or as part of an investigation or surgical procedure. A decrease in venous blood pressure is known to harm the heart's ability to move blood into the arterial side of the cardiovascular system. This is because cardiac output is directly related to venous return, which is determined in part by venous blood pressure.

[0004] In many cases, a decrease in venous blood pressure can result from loss of blood volume (due to internal or external bleeding) and / or venous dilation, which can be caused by many conditions, including sepsis, anaphylaxis, spinal cord injury, and drug interactions.

[0005] Currently known pharmacological treatments for acute, severe venous dilation are limited and have low efficacy. For example, in cases of anaphylaxis, administration of adrenaline can increase peripheral vascular resistance and cardiac function, but does not increase venous tone. As a result, the primary treatment methodologies are administration of adrenaline, infusion of fluids, cardiopulmonary resuscitation, and time.

[0006] In surgery, approximately 1 in 10,000 patients suffer from anaphylactic reactions to drugs administered during the procedure. Compared to typical anaphylactic reactions to allergens encountered orally or by contact, anaphylactic reactions in the surgical environment generally have a rapid onset and are severe. Furthermore, when a patient develops an anaphylactic response to an intravenously administered drug, the histamine released in response to the allergen causes extensive venous dilation, which results in a greater volume of blood filling the veins and less blood volume available to stretch the veins and generate venous pressure. The fall in venous pressure reduces venous return and cardiac output, often leading to anaphylactic shock, which has a published mortality rate of 4% despite current management strategies. Summary of the Invention [Problem to be solved by the invention]

[0007] There is a need to address the above and / or at least provide a useful alternative. [Means for solving the problem]

[0008] summary A body compression system for use in applying compression to a patient positioned on a support surface is provided, a flexible sheet material disposed in at least two layers and defining an interior area therebetween, the layers being repositionable relative to one another such that the sheet material can assume a contracted state in which the amount of interior area is minimal; an overlay having an inlet orifice opening into the interior region; one or more restraints for, in use, providing and restraining an edge of the flexible sheet material relative to the support surface with at least a portion of the patient's body between the support surface and the flexible sheet material; a gas supply system having an outlet connected or connectable to the inlet orifice, the gas supply system being configured to deliver gas through the outlet; Here, when using the body compression system, a flexible sheet material of the overlay is draped over the patient to provide a posterior layer in contact with the patient and a front layer spaced from the patient by the posterior layer; the flexible sheet material is restrained against a support surface by a restraint; The gas supply system is a body compression system operable to deliver gas through the inlet orifice to increase the volume of the interior region from a contracted state and establish increased pressure within the interior region, thereby compressing the patient between the posterior layer of the overlay and the support surface.

[0009] In at least some embodiments, a containment vessel configured to contain pressurized gas; a gas distribution circuit interconnecting the containment vessel with an exhaust; a pump having an outlet for discharging the gas; and further comprising one or more of an inlet connector and a gas distribution circuit, the inlet connector interconnecting the outlet with an independent supply of pressurized gas via the gas distribution circuit; wherein, upon use of the body compression system, the gas supply system is operable to deliver gas to the overlay at a first flow rate and a second flow rate, wherein the first flow rate is higher than the second flow rate, and wherein the gas supply system is configured to deliver gas at the second flow rate when pressure in the interior region exceeds atmospheric pressure.

[0010] An overlay for use in applying compression to a patient positioned on the support surface is also provided; a flexible sheet material disposed in at least two layers and defining an interior area therebetween, the layers being repositionable relative to one another to assume a contracted state in which the amount of interior area is minimal; and an inlet orifice opening into the interior region; Now, when using overlays, a flexible sheet material in a contracted state is draped over a patient to provide a rear layer in contact with the patient and a front layer spaced from the patient by the rear layer; a flexible sheet material is constrained relative to a support surface; An overlay in which gas is introduced into the interior region through an inlet orifice to increase the volume of the interior region from a contracted state and establish elevated pressure within the interior region, thereby compressing the patient between a posterior layer of the overlay and a support surface.

[0011] Preferably, during use of the body compression system, a portion of the rear layer conforms to the patient and the front layer expands when increased pressure is established within the interior region.

[0012] Preferably, the overlay includes a restraint for restraining the flexible sheet material to the support surface.

[0013] In at least some aspects, the restraints are attached to a flexible sheet material. In some aspects, each restraint is configured to surround a support surface. In such aspects, each restraint can include a releasable connection. The releasable connection can be a hook and loop material. In some alternative aspects, the releasable connection is a quick release buckle. Each restraint can include a length adjustment.

[0014] The layers of the overlay may include an inner layer, which will provide a rear layer when the overlay is in use, and an outer layer, which will provide a front layer when the overlay is in use. The inlet orifice may be formed in the outer layer. In embodiments where the restraints are attached to the flexible sheet material, at least some of the restraints are attached to the outer layer.

[0015] The inner layer may include one or more pleats extending along the length of the overlay. Alternatively or additionally, the inner layer may be made of a flexible sheet material having a higher elasticity in at least one direction than the material of the outer layer. In an embodiment, the inner layer is made of a flexible sheet material having an elasticity in at least a lateral direction of the overlay that is higher than the elasticity of the flexible sheet material of the outer layer. The outer layer may be made of a flexible sheet material including a low elasticity cord. Alternatively or additionally, the overlay may include one or more elongated members configured to support a hoop stress in one or more directions from the outer layer upon increased pressure in the interior region.

[0016] Preferably, the outer layer is made of a flexible sheet material that is substantially inelastic. In some embodiments, the outer layer is made of a flexible sheet material that includes a woven material and a coating that reduces the porosity of the woven material. In some embodiments, the inner layer is made of a flexible sheet material that includes a woven material and a coating that reduces the porosity of the woven material. The outer layer may be formed of a material that has a lower gas permeability than the material of the inner layer.

[0017] The flexible sheet material can include an upper peripheral edge and a lower peripheral edge, whereby when the overlay is in use, the lower peripheral edge is further from the patient's head than the upper peripheral edge. In some aspects, the overlay is wider at the upper peripheral edge than at the lower peripheral edge. Alternatively or additionally, the width of the overlay tapers in a direction away from the upper peripheral edge.

[0018] Preferably, the overlay has one or more markings to facilitate positioning of the flexible sheet material relative to the patient at defined locations.

[0019] The layers of flexible sheet material may be arranged to form distinct peripheral edges to the interior regions, hi some aspects, the peripheral edges of at least some of the interior regions are internally spaced from the peripheral edge of the outer layer.

[0020] The layers of the overlay may be made from separate pieces of flexible sheet material that are joined at the peripheral edges of the interior region.

[0021] In some embodiments, the layers of flexible sheet material are joined at their peripheral edges by at least one of a plastic weld, an adhesive, and a sewn seam. In examples where the layers of flexible sheet material are joined at their peripheral edges by a sewn seam, the overlay further includes a seam material across or within the seam.

[0022] In some aspects, the inlet orifice is part of the inlet connector and the outlet is part of an outlet connector that interconnects with the inlet connector. The inlet connector may include an inlet valve that is normally closed. In some aspects, connecting the outlet connector to the inlet connector causes the inlet valve to open. In some alternative aspects, the inlet valve includes an actuator operable to open the inlet valve.

[0023] The overlay may include a plurality of inlet orifices.

[0024] In some embodiments, the overlay includes one or more partitions of flexible sheet material that divide the interior region into two or more pockets, where the partitions inhibit gas flow between the pockets, and where one of the inlet orifices opens into the interior region within each respective pocket.

[0025] In at least some aspects, the flexible sheet material of the overlay is configured to be in a contracted state when placed on the patient.

[0026] The overlay may include an overpressure relief valve for venting excess pressure from the interior region to the atmosphere. In some embodiments, the overpressure relief valve opens when the interior pressure in the interior region exceeds a predetermined pressure. In some examples, the predetermined pressure is 60 cm of water or less.

[0027] A gas delivery system for use with the overlay of the body compression system is also provided; an outlet connected or connectable to an inlet orifice of the overlay; a pump in communication with the outlet via a conduit; a containment vessel in communication with the exhaust through a gas distribution circuit, the containment vessel configured to contain a pressurized gas; and and one or more of an inlet connector for interconnecting with an independent supply of pressurized gas, and a gas distribution circuit including one or more conduits directing gas from the inlet connector to an outlet; Here, when using a gas supply system in a body compression system, the gas supply system is operable to deliver gas at a first flow rate and a second flow rate, the first flow rate being higher than the second flow rate; and The gas supply system is a flowable material supply system configured to deliver gas at a flow rate up to a second flow rate when pressure in the interior region exceeds a predetermined pressure.

[0028] In some embodiments where the gas supply system includes a pump, the pump preferably comprises: an electric motor connected to the rotor that is rotatable to displace gas from the inlet to the outlet through a chamber in which the rotor is housed; an exhaust connector interconnecting the exhaust port with a complementary connector in communication with an inlet orifice of the overlay; at least one flow sensor and pressure sensor disposed between the chamber and the outlet; a controller configured to control operation of the electric motor, the controller configured to receive information from the flow sensor and / or the pressure sensor, and to drive the electric motor to vary the flow rate of gas to the exhaust in response to the received information; At least one self-contained power source and a connector for connecting the pump to a stand-alone power source to provide power to the electric motor.

[0029] The controller may be configured such that the pump is operable at a first flow rate to inflate the overlay and establish and / or maintain an elevated pressure within the interior region at a flow rate up to a second flow rate, the first flow rate being higher than the second flow rate.

[0030] In certain embodiments, the controller is configured such that, when initiated, the controller initially drives the electric motor to supply gas to the outlet at a first flow rate.

[0031] In some embodiments, the controller is configured such that when started, the controller drives the electric motor to supply gas to the outlet at a first flow rate for a predetermined period of time. In some embodiments where the pump includes a flow sensor, the controller is configured such that when started, the controller drives the electric motor to supply gas to the outlet at a first flow rate to exhaust a predetermined amount of gas, and thereafter drives the electric motor to supply gas to the outlet at a flow rate up to a second flow rate. In some where the pump includes a pressure sensor, the controller is configured such that when the sensed pressure is at or below a predetermined pressure threshold, the controller drives the electric motor to supply gas to the outlet at a first flow rate to exhaust a predetermined amount of gas, and when the sensed pressure exceeds the predetermined pressure threshold, the controller drives the electric motor to supply gas to the outlet at a flow rate up to the second flow rate.

[0032] In at least some aspects, the controller has a predetermined pressure set point, and is configured to operate on the electric motor to vary the flow rate of gas to the outlet to maintain pressure at the pressure set point within the interior region of the overlay. Preferably, the pump has an input user interface that allows a user to set the predetermined pressure set point. Alternatively or additionally, the pressure set point is adjustable during operation of the pump.

[0033] Preferably, the pump has an initial pressure set point and the controller is initiated at a predetermined pressure set point.

[0034] In some aspects, the predetermined pressure threshold is less than the pressure set point. Alternatively or additionally, the predetermined pressure threshold is a fraction of the pressure set point.

[0035] In some embodiments of the body compression system, the gas supply system includes an electrically powered pump. The pump includes an outlet connector defining an outlet, and an electrical switch operable to start an electric motor of the pump; and the overlay includes a conduit interconnected at a first end to the flexible sheet material such that the conduit opens into the inlet orifice, the second end of the conduit including an inlet connector releasably coupleable to the outlet connector; Here, the act of mating the inlet connector with the outlet connector operates an electrical switch.

[0036] Preferably, the inlet and outlet connectors are configured such that built-up pressure within the conduit urges the inlet and outlet connectors into a mated state. Alternatively or additionally, the pump may include a spring positioned to urge the inlet and outlet connectors into a mated state.

[0037] In at least one form, the inlet and outlet connectors form a bayonet mount and the electrical switch is positioned relative to the outlet connector to be actuated after a first action of coupling the inlet and outlet connectors is completed. Alternatively or additionally, the electrical switch is positioned relative to the outlet connector to be actuated during a first action of separating the inlet and outlet connectors.

[0038] In some aspects, where the gas supply system includes a containment vessel, the gas supply system further comprises: a discharge flow regulator for regulating gas flow from the containment vessel to the discharge outlet; exhausting gas to the exhaust outlet at a flow rate up to a first flow rate when pressure in the interior region is at or below a pressure threshold; and The regulator is configured to exhaust gas to the exhaust port at a flow rate up to a second flow rate when pressure in the interior region exceeds a pressure threshold and is below a predetermined pressure and / or a selected pressure setpoint.

[0039] In some embodiments, the first flow rate corresponds to a substantially unregulated exhaust of gas from the containment vessel to the exhaust outlet.

[0040] In some embodiments, the exhaust flow regulator has a plurality of gas-operated valves in fluid communication with the interior region via the inlet orifice and the exhaust, where each valve is operable to open at a unique pressure threshold. The exhaust flow regulator may include a first stage regulator that, when open, regulates the flow of gas from the containment vessel at a rate up to a first flow rate, and a second stage regulator that regulates the flow of gas to the exhaust at a rate up to a second flow rate when the pressure in the interior region exceeds a predetermined pressure, where the predetermined pressure is less than a pressure set point.

[0041] In some alternative embodiments, the exhaust flow regulator comprises: one or more electrically operated valves; at least one flow sensor and a pressure sensor disposed between the chamber and the outlet; an electronic controller for controlling operation of the valve, the controller being configured to receive information from the flow sensor and / or the pressure sensor and to operate the valve in response to the received information; At least one self-contained power source and a stand-alone power source that provides power to the electronic controller.

[0042] An overlay for use in applying compression to a patient positioned on a support surface is also provided, the overlay comprising: a flexible sheet material disposed in at least two layers and defining an interior area therebetween, the layers being repositionable relative to one another to assume a contracted state in which the amount of interior area is minimal; a compressible open cell material contained within the interior region; an inlet orifice opening into the interior region; an inlet valve operable to selectively allow passage of air through the inlet orifice; a restraint for restraining the flexible sheet material to a support surface, the restraint being adjustable in length; Now, when using overlays, an intake valve is opened to allow the compressible open cell material to fill the interior region and then closed to isolate the interior region from the atmosphere; the overlay is placed over the patient to provide a posterior layer in contact with the patient and a front layer spaced from the patient by the posterior layer; The restraint is used to restrain the flexible sheet material relative to the support surface, and the length of the restraint is adjusted to establish a tension in the front layer to establish increased pressure in the interior region, thereby compressing the patient between the rear layer of the overlay and the support surface.

[0043] In such an embodiment, the overlay includes at least one overpressure relief valve for venting excess pressure from the interior region to the atmosphere. [Brief description of the drawings]

[0044] In order that the present invention may be more readily understood, embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a schematic diagram of a body compression system according to a first embodiment of the present invention; [Diagram 2] FIG. 2 is a front plan view of an overlay of the body compression system of FIG. [Diagram 3] FIG. 3 is a rear plan view of the overlay of FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view of the body compression system taken along line A-A in FIG. [Diagram 5] FIG. 5 is a schematic cross-sectional view of the body compression system taken along line B-B in FIG. [Figure 6]FIG. 6 is a schematic cross-sectional view of the body compression system taken along line A-A in FIG. 1, showing the overlay in a contracted state; [Figure 7] FIG. 7 is a schematic block diagram of a pump of the body compression system of FIG. [Figure 8] FIG. 8 is a diagram of a user interface of the pump of the body compression system of FIG. [Figure 9] FIG. 9 is a chart showing overlay fill volume and interior zone pressure versus time for the body compression system of FIG. [Figure 10] FIG. 10 is a schematic diagram of a gas supply system according to a second embodiment of the present invention; [Figure 11] FIG. 11 is a schematic diagram of a gas supply system according to a third embodiment of the present invention; [Figure 12] FIG. 12 is a schematic diagram of a body compression system according to a fourth embodiment of the present invention; [Figure 13] FIG. 13 is a front plan view of an overlay of a body compression system according to a fifth embodiment of the present invention; and [Figure 14] FIG. 14 is a plan view of the rear surface of the overlay of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] Detailed Description 1 to 6 show a body compression system 10 according to an embodiment of the present invention. In use, the compression system 10 is to apply compression to a patient P positioned on a support surface S, which may be, for example, the top surface of a surgical room bed.

[0046] The compression system 10 includes an overlay 12 and a flowable material delivery system, which in this embodiment is in the form of a pump 14. The overlay 12 includes a flexible sheet material disposed in layers 16, 18. An interior region 20 is defined between the layers 16, 18. Because the sheet material of the layers 16, 18 is flexible, the layers can be repositioned relative to one another. In this manner, the sheet material of the overlay 12 can assume a contracted state in which the amount of interior region 20 is minimal. FIG. 6 shows the overlay 12 in a schematic manner draped over a patient P in a contracted state. In this particular embodiment, the flexible sheet material of the overlay 12 is positioned to form a posterior layer 16 that contacts the patient P when the overlay 12 is draped over the patient P, and a front layer 18 that is spaced from the patient P by the posterior layer 16.

[0047] 2 is the front side of overlay 12, thus showing front layer 18. FIG. 3 is the back side of overlay 12, thus showing rear layer 16.

[0048] 2, overlay 12 further includes an inlet connector 22 within front layer 18. Inlet connector 22 defines an inlet orifice that opens into interior region 20. Pump 14, in this particular embodiment, has an outlet pipe 24 that is releasably connectable to inlet connector 22. In this manner, gas from pump 14 is delivered into interior region 20 through outlet pipe 24.

[0049] In this example, pump 14 has an inlet (not shown) that draws in atmospheric air, and a rotatable rotor (not shown) to displace gas from the inlet to an outlet through a chamber (not shown) in which the rotor is housed.

[0050] The compression system includes a restraint 26 for providing and restraining a side edge portion of the flexible sheet material of overlay 12 against support surface S. In this particular embodiment, restraint 26 is integrated into overlay 12. In Figures 1 and 4-6, restraint 26 extends underneath and therefore around the operating room bed.

[0051] During use of the body compression system 10, the overlay 12 in a contracted state is draped over the patient P such that the rear layer 16 is in contact with the patient P and also with the support surface S. The front layer 18 faces outwardly and away from the patient P. The overlay 12 is restrained against the support surface S by the restraint 26. The pump 14 is then operated to deliver air through the inlet orifice to increase the volume of the interior region 20 from the contracted state. Once the interior region 20 is filled to its available capacity, the pump 14 then establishes an increased pressure within the interior region 20. The pressure difference between the interior region 20 and the surrounding atmosphere, together with the tensile force generated by the restraint 26, compresses the patient P between the rear layer 16 of the overlay 12 and the support surface S. Due to the flexibility of the sheet material, the rear layer 16 at least partially conforms to the patient's body. In this regard, it will be appreciated that due to various factors, there will be voids in some areas between the patient P and the overlay, and in some cases, the support surface S as well. Despite such gaps, the compressive force applied by overlay 12 is distributed substantially around the exterior surface of the patient's body that faces away from support surface S.

[0052] As shown in FIG. 1, when the overlay 12 is in its contracted state and draped over the patient P, the upper edge 28 of the overlay 12 should be positioned approximately level with the patient's xiphoid process. The lower edge 30 of the overlay 12 (which is the edge furthest from the patient's head) is placed at a position on the patient determined by the height of the patient P and the length of the overlay 12. To facilitate correct and optimal positioning of the overlay 12 on the patient, the front layer 18 of the overlay 12 has markings 32 to facilitate positioning of the flexible sheet material on the patient at a defined location. As shown in FIG. 2, in this example, the markings 32 consist of the word "xiphoid process" and an arrow with its tip pointing to the center of the upper edge 28. In the illustrated example, the lower edge 30 of the overlay 12 is positioned proximal to the patient's ankle.

[0053] As will be apparent, when overlay 12 is inflated and pressurized, compression system 10 applies a pressure that compresses patient P, effectively "squeezing" the portion of the patient's body that is underlying the flexible sheet material. Depending on the amount of pressure applied by compression system 10, there are various benefits that may be obtained through the use of compression system 10. For patients experiencing extensive venous dilation, compression in this manner can increase the patient's venous return, which has the consequence of increasing cardiac output. Preliminary testing has demonstrated that compression systems can be used in combination with venous catheters up to 60 centimeters of water (hereinafter "cm H 2 1. In this regard, preliminary testing indicates that compression achieved by air pressure within interior region 20 up to and including 15 to 45 centimeters of water (hereinafter "cm H2O") is beneficial in redistributing venous blood to restore functional cardiac output in the presence of venous dilation. 2 3. Further, testing has shown that compression achieved by air pressure within interior region 20 in the range of 25 to 35 centimeters of water column (hereinafter "cm H 2 O") is particularly beneficial. 2 This suggests that compression achieved by air pressure within interior region 20 in the range of 0″ (0″) may be highly effective in treating venous dilation.

[0054] In the illustrated example, the compressed portions of the patient P are their abdomen and legs. A majority of a human's venous blood volume is stored in the person's abdomen and legs. As illustrated in FIG. 1, application of the compression system 10 to the patient can redistribute the patient's venous blood to the head and chest regions.

[0055] Using an example, patients who suffer an anaphylactic reaction during a surgical procedure to an intravenously administered anesthetic likely had an allergen delivered rapidly through their bloodstream. The widespread presence of the allergen can induce a histamine response throughout much of their body. The ensuing venous dilation rapidly reduces venous blood pressure, which reduces venous return and therefore limits cardiac output. In severe cases, widespread venous dilation can lead to the death of the patient. The use of the compression system 10 may facilitate the management of an anaphylactic reaction in this context by redistributing venous blood, avoiding cardiac arrest due to loss of cardiac output. As long as the patient remains stable through external compression, and possibly enhanced by the infusion of adrenaline, the patient's natural histamine response has enough time to reverse the anaphylactic reaction. In other words, the body compression system can provide additional care to the use of adrenaline, intravenous fluids, and time in the treatment of an anaphylactic reaction.

[0056] As will be appreciated, this embodiment of the compression system 10 utilizes the support surface S on which the patient P lies in the application of compression, which has the distinct advantage of minimizing, if not eliminating, the need to move the patient in the application of the overlay to the patient.

[0057] For patients with certain injuries, such as internal venous bleeding from a pelvic fracture, application of compression using the compression system 10 of this embodiment can limit venous bleeding in the abdomen and / or lower extremities. As is evident, limiting venous bleeding can improve the prospects for recovery from the injury. By way of example, pelvic fractures are often accompanied by internal bleeding, which in some cases arises from the venous circulation. Because pelvic fractures are usually the result of accidental trauma, an accompanying emergency medical services (EMS) team will first stabilize the patient at the scene of the accident before transporting the patient to a hospital. During patient transport, it may be necessary to introduce fluids to compensate for venous bleeding and maintain venous return. A body compression system according to an embodiment of the present invention can be used by the EMS team during transport to limit venous bleeding and then limit the required fluid infusion. To this end, the patient is loaded onto an EMS stretcher, the compression system overlay is draped over the patient, and the patient can be restrained to the EMS stretcher using the system's restraints. When the flexible sheet material is expanded and pressurized, the overlay together with the stretcher cooperate to compress the patient, the compression acting to limit the extent of venous bleeding.

[0058] It will be appreciated that embodiment compression systems may alternatively or additionally be used in transporting patients with other injuries. One particular advantage is that compression may enhance the stability of the patient relative to the support surface on which the patient is positioned, which may help limit patient discomfort.

[0059] A further advantage of using a compression system in transport is that it operates in a similar manner to the safety restraints often placed on patients during transport.

[0060] To facilitate movement of the rear layer 18 during inflation, the rear layer 18 is provided with a pair of pleats 35. Each pleat 35 extends the length of the overlay 12.

[0061] As will be appreciated, the available volume of the interior region (in other words, the maximum amount available) depends on several factors, including the size of the patient P (and particularly his / her girth), the shape of the support surface S and the front layer 16, and the elasticity of the front layer 16. The front layer 16 in some embodiments may be made of a flexible sheet material that is substantially inelastic. This has the advantages of increasing the available volume, minimizing stretching of the front layer, avoiding changes in the permeability of the front layer (which can occur with some materials when stretched), and / or minimizing the possibility of material rupture in the front layer.

[0062] In one example, the front layer 16 is made of a flexible sheet material that includes a woven material and a coating that reduces the porosity of the woven material. The coating may be a polymer coating, such as, for example, a polyurethane or acrylic material, that may be applied to the woven material during the manufacture of the sheet material. Such a polymer coating may be beneficial in blocking the pores of the sheet material and therefore limiting gas permeability. Similar is true for the back layer 18.

[0063] In this particular embodiment, the overlay 12 is wider at the upper peripheral edge 28 than at the lower peripheral edge 30. Additionally, the width of the overlay 12 tapers in a direction away from the upper peripheral edge 28. This has the advantage of maximizing the contact surface between the overlay 12 and the patient P while also minimizing the maximum amount of interior region 20.

[0064] In the illustrated example, the layers 16, 18 of the overlay 12 are made from separate pieces of flexible sheet material that are joined at the peripheral edges of the interior region 20. In this manner, the layers 16, 18 of flexible sheet material form distinct peripheral edges to the interior region 20.

[0065] The restraints 26 are attached to the flexible sheet material of the overlay 12. In the embodiment illustrated in Figures 2 and 3, each restraint 26 has a length greater than necessary to encircle the support surface S when a patient P rests on the support surface S. Each restraint 26 has a releasable connection, which in this embodiment is in the form of hook and loop material 34, 36. In this example, hook material 34 is provided on a portion of the "free" section of the restraint 26. Loop material 36 is provided across the width of the flexible sheet material and on the exterior surface of the front layer 18.

[0066] A looped handle 38 is provided at the end of each restrainer 26 to facilitate restraining the overlay 12 to a bed providing the support surface S. When applying and restraining the overlay 12, the "free" section of each restrainer 26 is threaded under the support surface S and then positioned to interconnect the hook-and-loop fastener materials 34, 36. Two surgeons can quickly thread the looped handles 38 under the patient P to support the surface S while donning the overlay 12.

[0067] FIG. 7 is a block diagram of the components of the pump 14 of the body compression system 10 of FIG.

[0068] The pump 14 in this embodiment includes a brushless DC motor blower 40. Within the motor blower 40 is an electric motor connected to a rotor rotatable within a chamber. The motor blower 40 displaces air drawn from an intake 42 through the chamber by rotation of the rotor and out to an exhaust 44. As previously mentioned, the pump 14 includes an outlet pipe 24, which in this particular embodiment is formed at the inner end of the outlet pipe 24 that is permanently connected to the pump housing. At the outer end of the outlet pipe 24, the pump 14 has an exhaust connector (not shown) that interconnects the outlet with a (complementary) inlet connector 22 that communicates with an inlet orifice of the overlay 12.

[0069] The pump 14 includes a flow sensor 46 and a pressure sensor 48 disposed between a chamber and an outlet of the pump 14. As such, the flow sensor 46 measures the flow rate of air exhausted from the pump 14. From information obtained from the flow sensor 46, the fill volume of the interior region 20 of the overlay 12 can be determined with at least sufficient accuracy. The pressure sensor 48 measures the pressure of the air exhausted from the pump 14. As will be appreciated, the air pressure is substantially similar to the internal pressure within the interior region 20.

[0070] The pump 14 further includes a controller 50 that controls the operation of the motor blower 40. As shown in Figure 7, the controller 50 is configured to receive information from the flow sensor 46 and the pressure sensor 48. Thus, in response to the received information, the controller 50 can vary the electric motor speed to vary the flow rate of air to the exhaust.

[0071] In this particular embodiment, the pump 14 is also a self-contained power source, which in this embodiment is a non-isolated power source 52, such as a battery. An electrical connector (not shown) is also provided for connecting the pump to a stand-alone power source, such as a mains AC power source. The electrical connector is coupled to an isolated AC / DC power source 54. In this manner, the pump 14 can be powered from either a battery or a mains AC power source.

[0072] The controller 50 of this embodiment is configured such that the pump 14 is operable to inflate the overlay 12 at a first flow rate and to establish and / or maintain an elevated pressure within the interior region 20 at a flow rate up to a second flow rate. The first flow rate is higher than the second flow rate. In particular, the first flow rate may be utilized to provide a large amount of flow to the interior region 20, thereby enabling rapid inflation of the overlay 12. Once the maximum available capacity of the interior region 20 is reached, the pump 14 may then be operated at a second flow rate to establish and / or maintain an elevated pressure within the interior region 20. As will be appreciated, the second flow rate may be optimally matched to air leakage from the overlay 12, and in embodiments where air leakage is negligible, the pump 14 may be operable from a flow rate approaching zero.

[0073] Once the maximum available capacity of interior region 20 is reached, controller 50 may operate in a cyclical manner that involves alternating between the second flow rate and no output to maintain the elevated pressure. Alternatively, controller 50 may utilize a feedback loop control system in which the second flow rate is adjusted based on input from pressure sensor 48 and, in some cases, also flow sensor 46.

[0074] The controller 50 may also be configured such that, when started, the motor blower 40 is initially driven to supply air to the outlet at a first flow rate. In this manner, the controller 50 is operating under the starting assumption that the overlay 12 is in its deflated state. An atmospheric pressure sensor 47 is also provided which allows a comparison of the atmospheric pressure (obtained via the atmospheric pressure sensor) with data obtained by the pressure sensor 48. In particular, the pressure difference between the atmospheric pressure and the pressure at the outlet of the motor blower 40.

[0075] 9 is a chart showing the fill volume (shown as the plotted solid line on the chart and indicated by arrow V) and the internal zone pressure (shown as the plotted dashed line on the chart and indicated by arrow D) of overlay 12 versus time on the horizontal axis. FIG 9 also shows the flow rate of air expelled by pump 14 (shown as the plotted dash-dotted line on the chart and indicated by arrow F).

[0076] At time T=0, overlay 12 is in its deflated state, and therefore, fill volume V and interior region pressure D are both zero. Time T=0 represents the time when the gas supply system is started. In this example, the gas supply system delivers a substantially constant, high flow rate of air to overlay 12 between time T=0 and time T=t1. Thus, during this period, overlay 12 is inflated by a substantially constant amount (which is the higher first flow rate of pump 14), and fill volume V increases substantially linearly from zero to an amount approaching the maximum available capacity.

[0077] At time T=t1, overlay 12 is approaching its available capacity, and therefore, between time T=t1 and time T=t2, interior region pressure D increases in a non-linear manner from zero to an elevated pressure. Thus, during this period when interior region 20 of overlay 12 is pressurized to the elevated pressure, pump 14 is operating at the lower second flow rate.

[0078] After time T=t2, interior region pressure D should be maintained at the increased pressure. As will be appreciated, air leakage from overlay 12 will cause the pressure in interior region 20 to decrease over time while there is no air flow into interior region 20. Thus, after time T=t2, pump 14 is operated at up to the second flow rate.

[0079] In this example, the controller 50 is configured such that when the sensed pressure - obtained from the pressure sensor 48 - exceeds a predetermined pressure threshold, the controller 50 activates the motor blower 40 to switch the flow rate of the exhausted air from a first flow rate to a second flow rate. In this example, the defined pressure threshold is sensed at time T=t1.

[0080] It will be appreciated that the chart of FIG. 9 is only schematic and illustrative of one way in which the pump 14 may be operated.

[0081] As shown in Figure 7, pump 14 has a user interface 55 that includes an input user interface 56 that allows a user to operate the pump, and an output user interface 58 that provides visual information for the user to ascertain the operational status of pump 14. In one example, user interface 55 includes a touch screen display, as illustrated in Figure 8.

[0082] 8, user interface 55 allows a user to set a predetermined pressure set point, which is the desired maximum elevated pressure in interior region 20. Input user interface 58 may allow a user to adjust the pressure set point during operation of pump 14. To this end, user interface 55 may include a pressure set point of 20 cm H 2 O, 40cm H 2 O, and 60cm H 2 A "fast start" input 80 facilitates selection of pump operation to an initial pressure set point of O. The pressure set point may be adjusted either by decreasing the pressure set point using a pressure decrease input 82, or by increasing the pressure set point using a pressure decrease input 84. The user may immediately stop operation of the motor blower 40 via a "stop" input 88.

[0083] The output user interface 58 portion of user interface 55 indicates "SET PRESSURE" in display area 86. Additionally, the output user interface 58 portion of user interface 55 includes a pump operating parameters display portion 90, which includes digital gauges and numerical values ​​for each of the sensed pressure (via pressure sensor 48), the rotational speed of motor blower 40, and the temperature of the air flowing through motor blower 40.

[0084] In this particular embodiment, the output user interface 58 also provides information audibly via a speaker that allows the user to ascertain the operational status of the pump 14 .

[0085] It will be appreciated that the compression system of embodiments of the present invention may be used to treat other conditions including (but not limited to) distributive shock in the abdomen and / or lower extremities, hypotension, and external venous bleeding. It will be appreciated that the level of compression, which correlates to the internal pressure of the internal area, may vary depending on many factors, including (but not limited to) the condition being treated, the immediate event being treated, and the particulars of the individual being treated.

[0086] Moreover, compression is known to be beneficial in managing lactic acid buildup in soft tissues. Compression systems according to certain embodiments may be efficacious in athletic recovery. In such embodiments, it may be desirable for the air delivered to the interior region to be cooled in order to provide the dual benefits of compression and cryotherapy. In such an event, the compression system may include a heat exchanger configured to reduce the temperature of the air being delivered to the interior region. Such embodiments may include an air return line from the overlay to an inlet to the pump. The gas supply system may optionally include an atmosphere inlet and a valve to switch between intake air drawn from the atmosphere to the pump and air from the air return line. The heat exchanger may be provided in either the air return line, the inlet to the pump downstream of the valve, and the air exhaust line from the pump to the overlay. In this manner, the air within the interior region of the overlay may be maintained at a temperature below ambient temperature.

[0087] 10 illustrates a schematic of a gas supply system 114 according to a further embodiment. The gas supply system 114 includes a containment vessel, in this embodiment in the form of a gas cylinder 160, and an exhaust flow regulator. The exhaust flow regulator is configured to regulate the flow of gas from the gas cylinder 160 to an exhaust 144. The gas supply system 114 also includes conduits, such as hoses (not shown in FIG. 10), that interconnect various components of the gas supply system 114. The gas supply system 114 also includes an exhaust connector (not shown) that interconnects the exhaust 144 with a (complementary) inlet connector that is in communication with an inlet orifice of the overlay.

[0088] The regulator is configured to exhaust the gas to an exhaust port 144; a. a flow rate up to a first flow rate when the pressure in the interior region is within a first pressure range that includes atmospheric pressure and is up to a pressure threshold; b. A flow rate to a second flow rate that is lower than the first flow rate when the pressure in the interior region is within a second pressure range that exceeds the pressure threshold and the defined pressure and / or selected pressure set point.

[0089] The defined pressure / selected pressure set point is greater than the pressure threshold. The pressure threshold is greater than atmospheric pressure.

[0090] In the illustrated embodiment, the regulator includes a first stage regulator 162 that reduces the pressure of gas from a gas cylinder 160. As shown generally in Figure 10, a conduit 164 on the outlet side of the first stage regulator 162 branches to a second stage primary regulator 166, and a second stage secondary regulator 168. On the outlet side of each of the second stage primary and secondary regulators 166, 168 are a pair of conduits 170 that join to lead to the outlet 144.

[0091] As will be appreciated, during use of the gas supply system 160 in a body compression system, the pressure within the pair of conduits 170 is substantially equal to the internal pressure of the interior region of the overlay. The second stage primary regulator 166 is configured to supply gas to the conduit 170a, and thus the outlet 144, at a high flow rate (which is a first flow rate). The second stage primary regulator 166 is a demand valve that opens when the pressure within the conduit 170a falls below a pressure threshold. When the pressure within the conduit 170a rises above the pressure threshold, the second stage primary regulator 166 closes.

[0092] The second stage secondary regulator 168 is configured to supply gas at a low flow rate (which is a second flow rate) to the conduit 170b and thus to the outlet 144. The second stage secondary regulator 168 is a demand valve that is closed when the pressure in the conduit 170b is at atmospheric pressure. As the pressure in the conduit 170b increases and approaches a pressure threshold, the second stage secondary regulator 168 opens. Additionally, when the pressure in the conduit 170b is at a defined pressure / selected pressure set point, the second stage secondary regulator 168 closes so that there is no gas flowing to the outlet 144. As will be appreciated, it is advantageous for both the second stage primary and secondary regulators 166, 168 to open in a narrow pressure range that includes the pressure threshold to ensure flow continuity to the overlay during expansion.

[0093] The gas supply system 160 includes a pair of valves 172 on a pair of conduits 170 which provide the ability to manually adjust the flow rate through either conduit 170a, 170b if desired.

[0094] The second stage secondary regulator 168 may include a regulator that allows the pressure set point to be adjusted, if desired.

[0095] 11 illustrates a schematic diagram of a gas supply system 214 according to another embodiment. The gas supply system 214 includes a container of pressurized gas, in this embodiment in the form of a gas cylinder 260, a gas distribution circuit 270 including an inlet connector 272 for interconnecting with an independent supply of pressurized gas, such as a medical gas supply line 290.

[0096] The gas supply system 214 includes a first conduit 274 connected to the outlet of the gas cylinder 260 and a second conduit 276 connected to the inlet connector 272. The first and second conduits 274, 276 are joined at a junction 278, and a third conduit 280 extends from the junction 278 to the outlet 244. In this manner, gas can flow from the medical gas supply line 290, through the inlet connector and the second and third conduits 276, 280, to the outlet 244. Additionally, gas can also flow from the gas cylinder 260 through the first and third conduits 274, 280 to the outlet 244.

[0097] The second conduit 276 is provided with a gate valve 282 and a check valve 283. In this example, the gas cylinder 260 is a single-use cylinder. The act of opening the gate valve 282 simultaneously penetrates the seal of the gas cylinder 260 and releases gas from within the cylinder. In this embodiment, the gas flow from the gas cylinder 260 is substantially unregulated. The amount of gas contained within the cylinder (at elevated pressure) is substantially equal to the maximum available volume of the interior region of the overlay. Thus, as gas from the gas cylinder 260 is depleted, the overlay expands. Thus, in this particular embodiment, the first flow rate corresponds to a substantially unregulated discharge of gas from the gas cylinder 260.

[0098] When the gas cylinder is substantially depleted, gas inflow from the medical gas supply line 290 becomes dominant and provides gas flow to the outlet 244 at the lower second flow rate. The gate valve 282 is also configured to operate as a demand valve, thereby allowing flow through the second conduit 276 only when the pressure in the second conduit 276 is at or below the pressure set point. The check valve 283 prevents backflow of gas from the system 214 to the medical gas supply line 290.

[0099] As will be appreciated, the medical gas supply line 290 may have an appropriate pressure to achieve a desired pressure set point during use of the body compression system, but may have a very low flow rate, such that the time to inflate the overlay is unacceptably long. The "hybrid" gas supply provided by the gas supply system 214 allows for rapid inflation of the overlay using gas from the gas cylinder 260, while also allowing for a reliable and continuous supply of pressurized gas from the medical gas supply line 290.

[0100] In this particular embodiment, the third conduit 280 includes a bleed valve 284 that releases gas when the pressure in the third conduit 280 exceeds a limiting pressure. In cases where a body compression system including the gas supply system 214 is used with a patient of particularly large girth, the available volume may be less than the amount of gas (at elevated pressure) contained within the gas cylinder 260. In this scenario, excess high pressure gas may be vented through the bleed valve 284, minimizing the possibility of overlay leading to excessive pressure or damage to the body compression system.

[0101] Figure 12 illustrates a body compression system 310 according to another embodiment of the present invention. The body compression system 310 is substantially similar to the body compression system 10 of Figure 1. Thus, components of the body compression system 310 that are similar to components of the body compression system 10 have the same numbers with the prefix "3".

[0102] 12 shows the overlay 312 in a contracted state. The overlay includes a conduit 324 interconnected at a first end thereof to the rear layer of flexible sheet material 318 so as to open into the inlet orifice. At a second end of the conduit 324 is an inlet connector 392.

[0103] The pump 314 includes an outlet connector 394 that defines the outlet 344, and an electrical switch (not shown) operable to activate an electric motor of the pump 314. The inlet connector 392 is releasably matable to the outlet connector 394. In this example, the inlet connector 392 and the outlet connector 394 form a bayonet mount. The act of mating the inlet connector 392 with the outlet connector 394 operates the electrical switch.

[0104] In this example, the electrical switch is positioned relative to the outlet connector 394 so as to be actuated after a first action of coupling the inlet connector 392 and the outlet connector 394 is completed. Additionally, the electrical switch is positioned relative to the outlet connector 394 so as to be actuated during a first action of separating the inlet connector 392 and the outlet connector 394.

[0105] 13 and 14 show an overlay 412 according to a fourth embodiment, the overlay 412 being for use in a body compression system. The overlay 412 is substantially similar to the overlay 12 of the body compression system 10 of FIG 1. Thus, components of the overlay 412 that are similar to components of the overlay 12 have the same numbers with the prefix "4".

[0106] Overlay 12 has a flexible sheet material disposed in layers 416, 418. Figure 13 shows the front side of overlay 412, hence front layer 418. Figure 14 shows the back side of overlay 412, hence back layer 416.

[0107] An interior region (not shown in Figures 13 and 14) is defined between layers 416, 418. The sheet material of layers 416, 418 is flexible so that the layers can be repositioned relative to one another. In a more preferred embodiment, the flexible sheet material is a laminate of nylon and thermoplastic polyurethane. This material has the advantage of having a low air flow rate through the material. Additionally, the material can be joined by heat welding, which minimizes holes (and therefore leaks) at the seams.

[0108] To facilitate movement of the rear layer 416 during inflation, the portion of the flexible sheet material forming the rear layer 416 is wider than the portion of the flexible sheet material forming the front layer 418. To accommodate the difference in width of the flexible sheet material portions of the layers 416, 418, the rear layer 416 is formed with pleats 435. Each pleat 435 extends along the length of the overlay 412 from one of the top edge 428 or bottom edge 430 of the overlay 412. In this particular embodiment, the overlay 412 has eight pleats 435, four of which are approximately evenly distributed along the top edge 428 and four of which are distributed at the bottom edge 430. As shown in FIG. 14, the center two of the four pleats 435 at the bottom edge 430 are near each other at the centerline of the overlay 412.

[0109] The overlay 412 further has an inlet connector 422 in the front layer 418. The inlet connector 422 defines an inlet orifice that opens into the interior region. The pump 14, in this particular embodiment, has an outlet pipe 24 that is releasably connectable to the inlet connector 22. In this manner, gas from the pump 14 is delivered into the interior region 20 through the outlet pipe 24.

[0110] The overlay 412 has four restraints 426 for restraining the overlay 412 to a support surface S, such as a bed. In this embodiment, the restraints 426 are attached to the front layer 418. The length of each restraint 426 is sufficient to extend under and therefore around the operating room bed and the patient, overlapping on itself.

[0111] Each restraint 426 has a releasable connection, which in this embodiment is in the form of hook and loop material 434, 436. In this example, hook material 434 is provided on a portion of the "free" section of the restraint 426. Loop material 436 is provided across the width of the flexible sheet material and on the outer surface of the front layer 418. Each restraint 426 includes a looped handle 438 at an end of each restraint 426.

[0112] A body compression system according to embodiments may find possible use in scenarios and fields including, but not limited to: Treatment of distributive shock: -Sepsis in which vascular status improves with short-term evaluation and / or long-term treatment with replacement of fluid volume; - Anesthesia-related hypotension; Placement of a central venous line (CVL), which allows the patient's veins to expand when venous pressure increases, making them easier to puncture. Short-term management of venous bleeding; Central system investigation: -Cardiopulmonary resuscitation (CPR) to increase cardiac preload; -Abdominal compressions intervening during CPR by providing compression to the patient's entire body, including below and around the abdomen; -dobutamine stress echo to stop SAM caused by blood redistribution from dobutamine venous dilation), and - Cardiac preload stress to assess diastolic heart failure; Transporting distressed trauma patients: - Intra-abdominal, such as abdominal aortic aneurysm (AAA), pelvic injury (including pelvic fracture), or lower extremity bleeding; and - Fractures of the lower limbs; and athletic recovery and treatment.

[0113] One common element to all uses of body compression systems is the need for the temporary application of compression to the abdomen and lower extremities of a patient positioned on a support surface.

[0114] As described above, embodiments of the body compression system may be used with operating room beds and EMS stretchers. It will be appreciated that embodiments of the body compression system may be used with many other objects that provide a support surface on which a person may be positioned. These include (but are not limited to) spine boards, split board stretchers, hospital trolleys, beds, and specialized patient bed procedures.

[0115] It will be understood that pressure values ​​given throughout this specification and claims are gauge pressures (not absolute pressures) unless the context dictates otherwise.

[0116] Throughout this specification and the claims that follow, unless the context requires otherwise, the word "comprises" and variations such as "comprises" and "comprising" will be understood to mean the inclusion of a stated integer or step or group of integers or steps without excluding any other integers or steps or group of integers or steps.

[0117] Reference in this specification to any prior publication (or information derived therefrom) or to any known matter is not, and should not be construed as, an acknowledgment or admission, or in any way a suggestion, that the prior publication (or information derived therefrom) or known matter forms part of the general knowledge in the relevant field of endeavor.

Claims

1. An overlay for use in applying compression to a patient positioned on a support surface of an operating room bed, comprising: Here, the overlay includes inner and outer layers, an inlet orifice, and a restraint. wherein the inner and outer layers are made of flexible sheet material, the inner and outer layers being arranged to form an upper peripheral edge of the overlay and a lower peripheral edge of the overlay, wherein an interior region is defined between the inner and outer layers; wherein the inner layer includes one or more pleats extending along the length of the overlay, the inner and outer layers being repositionable relative to one another such that the flexible sheet material may assume a contracted state having a minimal amount of interior area; and wherein the inlet orifice opens into the interior region; wherein the restraint is attached to the outer layer; wherein each restraint has a length greater than a length necessary to encircle the patient and the operating room bed when the patient is resting on the support surface, and each restraint includes a releasable connection; Now, when using overlays, the inner layer and the outer layer are draped over the patient in a contracted condition such that the inner layer provides a posterior layer in contact with the patient and the outer layer provides a front layer spaced from the patient by the posterior layer, the lower peripheral edge being further from the patient's head than the upper peripheral edge; the inner layer and the outer layer are restrained relative to the support surface by a restraint; An overlay in which gas is introduced into the interior region through the inlet orifice to increase the volume of the interior region from a contracted state and establish increased pressure within the interior region, thereby compressing the patient between a posterior layer of the overlay and a support surface.

2. The overlay of claim 1 , wherein each pleat extends lengthwise of the overlay from one of the upper peripheral edge or the lower peripheral edge.

3. 3. The overlay of claim 1 or 2, wherein the overlay has eight pleats, four pleats distributed approximately evenly along the upper peripheral edge and four pleats along the lower edge.

4. wherein, in use, a portion of the rear layer conforms to the patient and when increased pressure is established within the interior region, the front layer expands; The overlay of any one of claims 1 to 3, wherein the overlay includes a restraint for restraining the flexible sheet material to a support surface.

5. The overlay of claim 1 , wherein each releasable bond is in the form of a hook and loop fastener material.

6. 6. The overlay of claim 5, wherein each restraint has a free section, and the hook fastener material is provided on a portion of the free section of the restraint.

7. 7. The overlay of claim 5 or 6, wherein loop material is provided on the outer surface of the front layer across the width of the flexible sheet material.

8. 8. The overlay of claim 1, wherein each restraint includes a looped handle at an end of each restraint.

9. 9. The overlay of any one of claims 1 to 8, wherein at least one of the inner and outer layers is made of a flexible sheet material that includes a woven material and a coating that reduces the porosity of the woven material.

10. 10. The overlay of claim 1, wherein the overlay is wider at an upper peripheral edge than at a lower peripheral edge.

11. 11. The overlay of any one of claims 1 to 10, wherein when in use, gas is introduced into the interior region, the pressure differential between the interior region and the surrounding atmosphere, together with the tension force generated by the restraint, compresses the patient between the posterior layer of the overlay and the support surface.

12. An overlay as described in any one of claims 1 to 11, wherein the inlet orifice is part of the inlet connector.

13. A body compression system comprising:

13. A method for manufacturing a gas supply system comprising: wherein the gas supply system includes a pump having an electric motor connected to a rotor that is rotatable to displace gas from the inlet to the outlet, the pump being operable to deliver gas through the outlet, through a chamber in which the rotor is housed; wherein the conduit is releasably connectable to an inlet connector of the overlay and to an outlet of the gas supply system; Here, when using the body compression system, the inner and outer layers of the overlay are draped over the patient in a contracted condition such that the inner layer provides a posterior layer in contact with the patient and the outer layer provides a front layer spaced from the patient by the posterior layer, the lower peripheral edge being further from the patient's head than the upper peripheral edge; wherein the inner and outer layers of the overlay are restrained relative to a support surface by restraints; The body compression system, wherein the gas supply system is operable to deliver gas via a conduit from the outlet to the inlet connector to increase the volume of the interior region from a contracted state and establish increased pressure within the interior region, thereby compressing the patient between the rear layer of the overlay and the support surface.

14. wherein the gas supply system further includes a controller for controlling operation of the pump; A controller having at least one pressure set point, 14. The body compression system of claim 13, wherein the controller is configured to operate on the electric motor to vary the flow of gas to the exhaust to inflate the overlay and maintain pressure within the interior region of the overlay at a pressure set point.

15. The body compression system of claim 14, wherein the pump has an input user interface that enables a user to set a predetermined pressure set point.

Images