Arm cannula retention apparatus

Abstract

An arm cannula retention apparatus is disclosed comprising a rigid support member configured to engage against a limb and retention strapping for securing the support member to the limb. A rigid protective shield is mounted relative to the rigid support member by releasable strapping and is shorter in longitudinal extent than the rigid support member. The rigid protective shield overlies a catheter of an arm cannula without contacting the catheter and is arranged to avoid obstruction of the retention strapping. The releasable strapping is independently releasable to allow access to the catheter while the rigid support member remains secured to the limb. The apparatus may be configured for use on a hand or across a joint such as an elbow, providing limb stabilisation and localised protection of the cannula insertion site.

Description

Arm Cannula Retention ApparatusField of the Invention

[0001] The present disclosure relates to medical devices for securing intravenous cannulas. More particularly, the disclosure relates to an apparatus for stabilising a limb in the region of a cannula insertion site while protecting the cannula and associated tubing from external interference and permitting selective access to the insertion site.Background of the Invention

[0002] Intravenous cannulas are commonly used in clinical and hospital settings to provide vascular access for the administration of fluids, medications, blood products, or for blood sampling. Once inserted, a cannula typically includes a catheter that remains positioned within a vein, together with associated tubing that extends away from the insertion site. Maintaining the position and integrity of the cannula during use is important, as unintended movement can lead to discomfort, infiltration, occlusion, or loss of venous access.

[0003] A range of devices and techniques have been developed to protect cannula insertion sites and to reduce the likelihood of disturbance during patient movement. Such approaches may involve the use of dressings, splints, shields or restraint structures that are secured to the limb in the vicinity of the cannula.

[0004] For example, US 4870976 A (DENNY THOMAS A) discloses various embodiments of an injection site shield assembly in which a rigid, generally semi- cylindrical protective member is positioned over an intravenous needle and tubing and secured to a patient’s limb using straps. The disclosed arrangements provide a protective enclosure over the injection site, with the shield extending along a substantial length of the limb and being retained in place by circumferential strapping.

[0005] WO 2011 / 040815 A1 (IQ & INVEST N V et al.) describes a guard device for protecting a percutaneous infusion port, particularly on the hand. The device includes a rigid splint body shaped to support the limb and a transparent guard body that is pivotally attached to the splint body and retained using a strap. The guard bodyprovides a protective cavity over the infusion site and allows visual inspection of the site through the transparent material.

[0006] US 5339834 A (MARCELLI EILEEN) discloses an infusion site cover and immobiliser comprising a two-part structure that encloses a limb around an intravenous catheter site. The disclosed device includes a cover portion with a window for viewing the insertion site and a base portion that supports the limb, with straps used to secure the components together around the limb to provide both protection and immobilisation.

[0007] While such devices demonstrate various approaches to shielding, supporting or immobilising a limb in the vicinity of an intravenous cannula, they also illustrate that different clinical situations may require different balances between protection, accessibility, comfort and freedom of movement. Accordingly, there remains an ongoing need to consider alternative configurations and arrangements for managing cannula insertion sites in a practical and clinically acceptable manner.

[0008] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.Summary of the Disclosure

[0009] The disclosure provides an arm cannula retention apparatus comprising a rigid support member configured to engage against a limb at or adjacent a cannula insertion site and retention strapping associated with the rigid support member for securing the rigid support member to the limb in use. The rigid support member provides a stable structural interface with the limb, allowing relative movement of the limb in the region of the cannula insertion site to be reduced when the apparatus is secured.

[0010] The apparatus further includes a rigid protective shield mounted relative to the rigid support member by releasable strapping. The rigid protective shield is shorter in longitudinal extent than the rigid support member and is arranged, in use, to overlie a catheter of an arm cannula without contacting the catheter. This configurationallows protection to be localised to the cannula insertion site while avoiding direct pressure on the catheter and associated dressing.

[0011] The rigid protective shield is arranged to avoid obstruction of the retention strapping, such that the rigid support member may remain secured to the limb independently of the presence or absence of the rigid protective shield. The releasable strapping is independently releasable relative to the retention strapping, permitting the rigid protective shield to be removed or displaced to allow access to the catheter while maintaining securement of the rigid support member to the limb. This arrangement enables protection of the cannula during normal use while allowing access for inspection, adjustment or treatment without disturbing the stabilised position of the limb.

[0012] In this manner, the apparatus provides a combination of limb stabilisation and localised cannula protection in which the functions of support and access are managed separately, allowing the apparatus to be applied to different anatomical regions and clinical situations while maintaining consistent control over the cannula insertion site.

[0013] The rigid support member may be configured to restrict movement of a region of the limb adjacent the cannula insertion site when secured by the retention strapping, thereby reducing transmission of limb movement to the catheter during use while allowing the apparatus to be removed when no longer required.

[0014] Preferably, the rigid protective shield defines a convex profile such that a clearance space is formed between the shield and the limb when the shield overlies the catheter. This clearance permits the catheter and any associated dressing to be accommodated without contact, while still providing a physical barrier against incidental impact or interference.

[0015] The rigid protective shield may define at least one entrance through which cannula tubing extends when the shield overlies the catheter. In certain arrangements, opposing entrances are defined at both longitudinal ends of the shield, allowing the tubing to extend from either end and facilitating flexible routing relative to the limb and surrounding equipment.

[0016] The rigid protective shield may be arranged to rest on the limb independently of the rigid support member when secured by the releasable strapping. In this configuration, the shield may conform to or accommodate variations in limb shape and surface profile across different anatomical regions, such that loads applied to the shield are borne primarily by the limb rather than being transmitted through the rigid support member. This can assist in maintaining stability of the catheter position while allowing the apparatus to be used across different anatomies without requiring precise alignment between the shield and the rigid support member.

[0017] For use on a hand, the rigid support member may comprise a planar support surface arranged to support the palm and, optionally, a curved cuff portion configured to engage around an underside of the wrist. This configuration allows the hand to be supported in a stable posture while distributing contact forces across the palm and wrist region.

[0018] For use on an arm, the rigid support member may be elongate and troughshaped to accommodate the arm along its length. The rigid support member may include proximal and distal portions arranged to engage opposite sides of a joint, such as an elbow, allowing the apparatus to be secured across the joint in a manner that limits relative movement of the joint while the cannula is in place.

[0019] Other aspects of the invention are also disclosed.Brief Description of the Drawings

[0020] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0021] Figure 1 shows a perspective view of an arm cannula retention apparatus configured for use on a hand, with retention strapping and releasable strapping open.

[0022] Figure 2 shows the apparatus of Figure 1 secured to the hand, with the rigid protective shield positioned over a catheter.

[0023] Figure 3 shows the apparatus of Figure 2 with the releasable strapping released and the rigid protective shield removed to expose the catheter.

[0024] Figure 4 shows a perspective view of an arm cannula retention apparatus configured for use on an arm, with retention strapping and releasable strapping open.

[0025] Figure 5 shows the apparatus of Figure 4 secured across an elbow joint with the rigid protective shield positioned over a catheter.

[0026] Figure 6 shows the apparatus of Figure 5 with the releasable strapping released and the rigid protective shield removed while the arm remains immobilised.Description of Embodiments

[0027] With reference to Figures 1 to 6, there is shown an embodiment of an arm cannula retention apparatus 100 comprising a rigid support member 101 configured to engage against a limb at or adjacent a cannula insertion site. In the illustrated embodiments, the rigid support member 101 provides a structural base against which the limb is supported in use, allowing forces applied to the apparatus 100 to be distributed over a larger surface area of the limb rather than being concentrated at the cannula insertion site. This arrangement assists in stabilising the limb region carrying the catheter while maintaining patient comfort.

[0028] Retention strapping 102 is associated with the rigid support member 101 and is configured to secure the rigid support member 101 to the limb in use. The retention strapping 102 may extend around the limb and engage back onto itself or onto the rigid support member 101 , thereby holding the rigid support member 101 in a fixed positional relationship relative to the limb. When secured in this manner, the rigid support member 101 resists relative movement between the limb and the apparatus100 in the vicinity of the cannula insertion site, reducing motion that could otherwise be transmitted to the catheter.

[0029] The apparatus 100 further comprises a rigid protective shield 103 mounted relative to the rigid support member 101 by releasable strapping 104. As illustrated in Figures 2 and 5, the releasable strapping 104 is distinct from the retention strapping 102 and functions to position and retain the rigid protective shield 103 over the cannula insertion site independently of the manner in which the rigid support member101 is secured to the limb. The rigid protective shield 103 is shorter in longitudinal extent than the rigid support member 101 , such that the shield 103 provides localisedcoverage of the cannula insertion site rather than extending along the full length of the support member 101.

[0030] In use, and as shown particularly in Figures 2 and 5, the rigid protective shield103 is arranged to overlie a catheter 106 of an arm cannula without contacting the catheter 106. The geometry and spacing of the rigid protective shield 103 relative to the limb allow a clearance region to be maintained above the catheter 106, thereby protecting the catheter 106 from external contact while avoiding direct pressure that could disturb its position or compromise patient comfort. Cannula tubing 105 extends from beneath the rigid protective shield 103, entering or exiting the shield 103 through an entrance defined at one end of the shield, as illustrated in Figures 2 and 5.

[0031] The rigid protective shield 103 is configured to avoid obstruction of the retention strapping 102. In the embodiments shown, the retention strapping 102 passes around the limb and the rigid support member 101 without being required to pass over or through the rigid protective shield 103. This separation of functions allows the rigid support member 101 to remain securely fixed to the limb irrespective of whether the rigid protective shield 103 is in place.

[0032] The releasable strapping 104 is independently releasable relative to the retention strapping 102. As illustrated in Figures 3 and 6, the releasable strapping104 may be disengaged to permit removal or lifting of the rigid protective shield 103 to access the catheter 106, while the retention strapping 102 remains secured to the limb and continues to hold the rigid support member 101 in position. This configuration enables inspection, adjustment or treatment of the cannula site without requiring removal or loosening of the rigid support member 101 from the limb, thereby reducing disturbance to the catheter and maintaining positional stability during such access.

[0033] In some embodiments the rigid support member 101 may be configured to immobilise movement of the limb in a region adjacent the cannula insertion site when secured by the retention strapping 102. In such embodiments, the rigid support member 101 provides a mechanically stiff interface that limits flexion, extension or rotational movement of the limb segment immediately surrounding the catheter 106.As shown in Figures 2 and 5, when the retention strapping 102 is tensioned around the limb, the rigid support member 101 resists bending or displacement of the limb relative to the catheter 106, thereby reducing transmission of movement to the catheter 106 and associated tubing 105. This immobilising effect may be particularly beneficial where the cannula insertion site is located near a joint or an area subject to frequent movement, as the rigid support member 101 acts as a stabilising structure that constrains motion locally without necessarily immobilising the entire limb. In this regard, the extent and degree of immobilisation may be influenced by the length, stiffness and contour of the rigid support member 101 , as well as the positioning and tension of the retention strapping 102, allowing the apparatus 100 to be adapted to different clinical requirements.

[0034] The rigid protective shield 103 preferably defines a generally convex profile, as illustrated in Figures 2, 3, 5 and 6. The convex geometry of the shield 103 may be selected such that, when positioned over the limb, a clearance space is created between an inner surface of the shield 103 and the outer surface of the limb. This clearance space allows the catheter 106 and any associated dressing to be accommodated beneath the shield 103 without direct contact, thereby reducing the likelihood of applied pressure disturbing the catheter position or causing discomfort. In certain arrangements, the curvature of the shield 103 may be greater than the natural curvature of the limb beneath it, such that any contact between the shield 103 and the limb occurs laterally adjacent the catheter 106 rather than directly above the insertion site.

[0035] The rigid protective shield 103 may define at least one entrance through which cannula tubing 105 extends when the shield 103 overlies the catheter 106. As shown in Figures 2 and 5, the entrance may be formed at a longitudinal end of the shield 103, allowing the tubing 105 to pass into or out of the region protected by the shield 103 without being sharply bent or compressed. The dimensions and contour of the entrance may be selected to accommodate different tubing sizes while maintaining shielding of the catheter 106 from external interference.

[0036] In preferred arrangements, the rigid protective shield 103 defines opposing entrances at both longitudinal ends of the shield 103. This permits the cannula tubing 105 to extend from either end of the shield 103, providing flexibility in tubing routing relative to the limb and surrounding medical equipment. Such an arrangement allows the apparatus 100 to be used in different orientations without requiring reconfiguration of the shield 103, thereby facilitating consistent protection of the catheter 106 across a range of clinical scenarios.

[0037] The rigid protective shield 103 may be configured to rest directly on the limb independently of the rigid support member 101 when secured by the releasable strapping 104. As illustrated in Figures 2, 3, 5 and 6, the shield 103 is positioned such that its load is borne by the limb surface rather than being transferred to the rigid support member 101. This arrangement allows the shield 103 to maintain a stable spatial relationship relative to the catheter 106 even if minor relative movement occurs between the rigid support member 101 and the limb. By decoupling the shield 103 from the rigid support member 101 in this manner, forces applied to the shield 103, for example due to incidental contact or external impact, are less likely to be transmitted through the rigid support member 101 and retention strapping 102 in a way that could disturb the catheter 106.

[0038] In the configurations shown, the releasable strapping 104 extends around the shield 103 and the limb to hold the shield 103 in its intended protective position while permitting the rigid support member 101 to perform its separate stabilising function. This separation of support paths allows the apparatus 100 to provide localised protection at the cannula insertion site while still allowing the rigid support member 101 to engage the limb in a manner optimised for overall stability and comfort.

[0039] The rigid support member 101 may comprise a planar support surface 107 arranged to support a palm of a hand, as illustrated in Figures 1 to 3. In this configuration, the planar support surface 107 provides a stable base against which the palm rests when the apparatus 100 is fitted, allowing the hand to be maintained in a generally open and supported posture. By supporting the palm in this manner, the rigid support member 101 assists in limiting involuntary hand movement that couldotherwise be transmitted to the catheter 106, while distributing contact pressure over a broad area of the palm to maintain comfort during extended use.

[0040] The rigid support member 101 may further comprise a curved cuff portion 109 arranged to engage around an underside of a wrist. As shown in Figures 1 and 2, the curved cuff portion 109 may extend proximally from the planar support surface 107 and define an ergonomic curvature that follows the natural contour of the wrist. This curvature allows the rigid support member 101 to seat securely against the wrist region when the retention strapping 102 is tightened, providing a stabilising anchor point for the apparatus 100. The curved cuff portion 109 may assist in resisting longitudinal movement of the rigid support member 101 relative to the hand, while still permitting the shield 103 and releasable strapping 104 to be independently manipulated to access the catheter 106.

[0041] The rigid support member 101 may be elongate and trough-shaped to accommodate an arm, as illustrated in Figures 4 to 6. In this configuration, the rigid support member 101 defines a longitudinal channel that partially surrounds the arm and distributes support along its length. The trough-shaped geometry allows the rigid support member 101 to cradle the arm in a stable manner while avoiding concentrated pressure points, thereby maintaining comfort while resisting movement of the arm relative to the apparatus 100. The elongate form also enables the rigid support member 101 to span across anatomical features such as joints while maintaining a consistent supporting interface.

[0042] In certain arrangements, the rigid support member 101 comprises a proximal portion 113 and a distal portion 112 arranged to engage opposite sides of an elbow joint, as shown in Figures 4 to 6. The distal portion 112 may be configured to engage the forearm region, while the proximal portion 113 may engage the region at or above the elbow. This segmentation allows the rigid support member 101 to conform more closely to the varying cross-sectional geometry of the arm along its length, while positioning the cannula insertion site at an intermediate location along the rigid support member 101 .

[0043] The retention strapping 102 may comprise proximal retention strapping 102A associated with the proximal portion 113 and distal retention strapping 102B associated with the distal portion 112. When secured, the proximal retention strapping 102A and distal retention strapping 102B engage the arm on opposite sides of the elbow joint, thereby resisting relative movement between the forearm and upper arm. In this arrangement, bending at the elbow is restricted while the rigid support member 101 remains secured in place. The rigid protective shield 103 is positioned between the proximal retention strapping 102A and the distal retention strapping 102B along the longitudinal extent of the rigid support member 101 , such that the shield 103 overlies the catheter 106 at a location that is stabilised by the surrounding jointimmobilising structure. This positional relationship allows the catheter 106 to be protected while benefiting from reduced joint-induced movement transmitted to the cannula insertion site.

[0044] The rigid support member 101 may comprise one or more slots 110 through which the retention strapping 102 passes. As illustrated in Figures 1 , 3, 4 and 6, the slots 110 may be formed through side regions or edge portions of the rigid support member 101 , allowing the retention strapping 102 to be threaded through the support member 101 rather than simply wrapped around it. This arrangement can assist in maintaining the positional alignment of the retention strapping 102 relative to the rigid support member 101 , reducing the likelihood of strap migration during use and helping to ensure that tightening forces are applied evenly across the support member 101 . The number, spacing and orientation of the slots 110 may be varied depending on the intended limb and desired strap routing.

[0045] The rigid support member 101 may additionally comprise a central protrusion 108 configured to support a central region of the limb and provide ergonomic curvature beneath the cannula insertion site. As shown in Figures 1 and 3, the central protrusion 108 may take the form of a dome or similar raised feature positioned on the planar support surface of the rigid support member 101. This protrusion 108 may provide contoured support to the palm or other limb region, encouraging a natural resting posture and distributing contact forces away from the cannula insertion site.In some arrangements, the central protrusion 108 may be integrally formed with the rigid support member 101 , while in other arrangements it may be formed as a separate component that is attached or overmoulded, allowing the firmness or profile of the protrusion 108 to be selected according to patient comfort or clinical preference.

[0046] The retention strapping 102 and the releasable strapping 104 may comprise press-contact fasteners, allowing the respective strapping to be secured and released quickly and reliably. In the embodiments illustrated in Figures 1 to 6, the press-contact fasteners permit the length and tension of the retention strapping 102 to be readily adjusted to accommodate different limb sizes, while similarly allowing the releasable strapping 104 to be engaged and disengaged to position or remove the rigid protective shield 103. The use of press-contact fasteners enables repeated opening and closing without significant degradation in performance, supporting frequent access to the catheter 106 when required.

[0047] In preferred implementations, the press-contact fasteners comprise hook-and- loop fasteners. This type of fastener allows the retention strapping 102 and the releasable strapping 104 to be secured over a wide range of overlap lengths, facilitating fine adjustment of fit and reducing the need for discrete buckle positions. Hook-and-loop fasteners also allow the strapping to lie relatively flat against the limb and the rigid support member 101 , reducing bulk and minimising snagging on external objects.

[0048] The retention strapping 102 may be configured to remain secured to the limb when the releasable strapping 104 is released. As shown in Figures 3 and 6, disengagement of the releasable strapping 104 allows the rigid protective shield 103 to be removed or lifted while the retention strapping 102 continues to hold the rigid support member 101 in place against the limb. This arrangement permits access to the catheter 106 without requiring repositioning of the rigid support member 101 , thereby maintaining limb stabilisation during inspection, adjustment or treatment of the cannula.

[0049] The rigid protective shield 103 may be configured to remain coupled to the releasable strapping 104 when the releasable strapping 104 is released. In the illustrated embodiments, the shield 103 remains tethered to the apparatus 100 by the releasable strapping 104 when opened, preventing unintended detachment or loss of the shield 103. This configuration allows the shield 103 to be readily repositioned over the catheter 106 after access, while ensuring that the shield 103 remains correctly oriented relative to the rigid support member 101 and the limb.

[0050] An exemplary, non-limiting method of use of the arm cannula retention apparatus 100 will now be described with reference to the hand-mounted and elbowmounted embodiments illustrated in Figures 1 to 6.

[0051] In a hand-mounted embodiment, as shown in Figures 1 to 3, the rigid support member 101 is first positioned such that the planar support surface 107 supports the palm of the hand, with the fingers extending beyond a front edge of the rigid support member 101. The curved cuff portion 109 is aligned beneath the wrist so that it conforms to the underside of the wrist region. The retention strapping 102 is then wrapped around the wrist and secured, for example by engagement of press-contact fasteners, to hold the rigid support member 101 firmly against the hand. At this stage, the rigid support member 101 stabilises the hand while distributing contact forces across the palm and wrist.

[0052] Once the rigid support member 101 is secured, the rigid protective shield 103 is positioned over the catheter 106 located on the back of the hand. The releasable strapping 104 is then engaged to hold the rigid protective shield 103 in place, such that the shield 103 overlies the catheter 106 without contacting it. Cannula tubing 105 is routed through an entrance defined by the rigid protective shield 103, allowing the tubing 105 to extend away from the protected region without sharp bending. If access to the catheter 106 is required, the releasable strapping 104 may be disengaged, as shown in Figure 3, allowing the rigid protective shield 103 to be lifted or removed while the retention strapping 102 remains secured around the wrist, thereby maintaining stabilisation of the hand during access.

[0053] In an elbow-mounted embodiment, as shown in Figures 4 to 6, the rigid support member 101 is positioned along the arm such that the distal portion 112 engages the forearm and the proximal portion 113 engages the region at or above the elbow joint. The rigid support member 101 may be oriented so that the elbow is received in a recessed or contoured region of the proximal portion 113. The distal retention strapping 102B is secured around the forearm and the proximal retention strapping 102A is secured around the upper arm, thereby fixing the rigid support member 101 to the arm on opposite sides of the elbow joint. This arrangement restricts bending of the elbow and stabilises the region adjacent the cannula insertion site.

[0054] With the rigid support member 101 secured, the rigid protective shield 103 is positioned between the proximal retention strapping 102A and the distal retention strapping 102B so that it overlies the catheter 106 located at or near the elbow. The releasable strapping 104 is then engaged to retain the rigid protective shield 103 in its protective position. Cannula tubing 105 is routed through an entrance defined by the rigid protective shield 103, allowing the tubing 105 to extend away from the elbow region without kinking. When inspection or adjustment of the catheter 106 is required, the releasable strapping 104 may be released, as illustrated in Figure 6, enabling removal or lifting of the rigid protective shield 103 while the retention strapping 102A, 102B remains secured, thereby maintaining immobilisation of the elbow during access.

[0055] In both embodiments, the method allows the rigid support member 101 to remain secured to the limb while the rigid protective shield 103 is selectively removed and replaced, providing protection of the catheter 106 during normal use and convenient access when required, without disturbing the stabilising engagement of the apparatus 100 with the limb.

[0056] The apparatus 100 described above provides a structured arrangement in which stabilisation of a limb and protection of a cannula insertion site are achieved through components that perform distinct, yet cooperative, functions. By securing the rigid support member 101 to the limb using retention strapping 102, relative movement of the limb in the region of the cannula insertion site can be reduced,thereby limiting forces transmitted to the catheter 106 during normal patient movement. This stabilising effect may be localised to the region of interest without requiring complete immobilisation of the entire limb.

[0057] The provision of a rigid protective shield 103 that is shorter than the rigid support member 101 allows protection to be concentrated at the cannula insertion site rather than along the full length of the limb. The clearance defined by the geometry of the shield 103 enables the catheter 106 and any associated dressing to be accommodated without direct contact, while still shielding the insertion site from incidental impact, snagging or compression. Routing of the cannula tubing 105 through one or more entrances defined by the shield 103 allows the tubing 105 to extend away from the insertion site in a controlled manner, reducing the likelihood of kinking.

[0058] Separation of the retention strapping 102 from the releasable strapping 104 permits the rigid support member 101 to remain secured to the limb while the rigid protective shield 103 is selectively removed. This arrangement allows inspection or adjustment of the catheter 106 to be carried out without disturbing the stabilised position of the limb, which can be particularly useful where repeated access is required. The ability for the shield 103 to remain coupled to the releasable strapping 104 when opened further supports consistent repositioning of the shield after access.

[0059] The apparatus 100 may be configured for use on different parts of the limb by varying the form of the rigid support member 101. For example, a planar support surface 107 and curved cuff portion 109 may be used to support the hand and wrist, while an elongate, trough-shaped configuration with spaced retention strapping may be used to span and limit movement of a joint such as the elbow. These configurations allow the apparatus 100 to be adapted to different clinical scenarios while maintaining the same underlying approach to stabilisation and protection.

[0060] Overall, the described arrangements enable controlled limitation of limb movement adjacent a cannula insertion site, protection of the catheter from external interference, and selective access to the insertion site, while allowing the apparatus100 to be adjusted and configured in a manner suited to the anatomical region and clinical requirements.

[0061] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practise the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed as obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.

Claims

Claims1. An arm cannula retention apparatus comprising a rigid support member configured to engage against a limb at or adjacent a cannula insertion site, retention strapping associated with the rigid support member and configured to secure the rigid support member to the limb in use, and a rigid protective shield mounted relative to the rigid support member by releasable strapping, the rigid protective shield being shorter in longitudinal extent than the rigid support member and arranged, in use, to overlie a catheter of an arm cannula without contacting the catheter, wherein the rigid protective shield is configured to avoid obstruction of the retention strapping, and wherein the releasable strapping is independently releasable relative to the retention strapping to permit removal of the rigid protective shield for access to the catheter while maintaining securement of the rigid support member to the limb by the retention strapping.

2. The arm cannula retention apparatus according to claim 1 , wherein the rigid support member is configured to immobilise movement of the limb in a region adjacent the cannula insertion site when secured by the retention strapping.

3. The arm cannula retention apparatus according to claim 1 , wherein the rigid protective shield defines a generally convex profile that provides a clearance space between the shield and the limb to accommodate the catheter without contact.

4. The arm cannula retention apparatus according to claim 1 , wherein the rigid protective shield defines at least one entrance through which cannula tubing extends when the shield overlies the catheter.

5. The arm cannula retention apparatus according to claim 4, wherein the rigid protective shield defines opposing entrances allowing the cannula tubing to extend from either end of the shield.

6. The arm cannula retention apparatus according to claim 1 , wherein the rigid protective shield is configured to rest on the limb independently of the rigid support member when secured by the releasable strapping.

7. The arm cannula retention apparatus according to claim 1 , wherein the rigid support member comprises a planar support surface arranged to support a palm of a hand.

8. The arm cannula retention apparatus according to claim 7, wherein the rigid support member further comprises a curved cuff portion arranged to engage around an underside of a wrist.

9. The arm cannula retention apparatus according to claim 1 , wherein the rigid support member is elongate and trough-shaped to accommodate an arm.

10. The arm cannula retention apparatus according to claim 9, wherein the rigid support member comprises a proximal portion and a distal portion arranged to engage opposite sides of an elbow joint.

11. The arm cannula retention apparatus according to claim 10, wherein the retention strapping comprises proximal retention strapping associated with the proximal portion and distal retention strapping associated with the distal portion so as to immobilise the elbow when the rigid support member is secured to the limb, and wherein the rigid protective shield is positioned between the proximal retention strapping and the distal retention strapping along a longitudinal extent of the rigid support member.

12. The arm cannula retention apparatus according to claim 1 , wherein the rigid support member comprises one or more slots through which the retention strapping passes.

13. The arm cannula retention apparatus according to claim 1 , wherein the rigid support member comprises a central protrusion configured to support a central region of the limb and provide ergonomic curvature beneath the cannula insertion site.

14. The arm cannula retention apparatus according to claim 1 , wherein the retention strapping and the releasable strapping comprise press-contact fasteners.

15. The arm cannula retention apparatus according to claim 14, wherein the presscontact fasteners comprise hook-and-loop fasteners.

16. The arm cannula retention apparatus according to claim 1 , wherein the retention strapping is configured to remain secured to the limb when the releasable strapping is released.

17. The arm cannula retention apparatus according to claim 1 , wherein the rigid protective shield is configured to remain coupled to the releasable strapping when the releasable strapping is released, such that the rigid protective shield is retained with the apparatus when not positioned over the catheter.

18. A method of retaining an arm cannula using the apparatus according to claim 1 , the method comprising securing the rigid support member to a limb using the retention strapping, positioning the rigid protective shield over a catheter using the releasable strapping, and releasing the releasable strapping to access the catheter while maintaining the rigid support member secured to the limb by the retention strapping.

19. The method according to claim 18, wherein the limb is immobilised by the rigid support member during use of the arm cannula to reduce movement of the catheter.

20. The method according to claim 18, wherein the retention strapping comprises proximal retention strapping and distal retention strapping positioned on opposite sides of a joint of the limb so as to immobilise the joint when the rigid support member is secured to the limb, and wherein the rigid protective shield is positioned between the proximal retention strapping and the distal retention strapping along a longitudinal extent of the rigid support member.

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