Vasodilation assembly

1. A vasodilation assembly for facilitating intravenous cannulation, the vasodilation assembly comprising:

(i) a flexible plastics sleeve;

(ii) a heated air supply; and

(iii) a conduit for conveying heated air from the heated air supply into the flexible plastics sleeve;

wherein the flexible plastics sleeve is of a double-walled construction comprising inner and outer sleeve layers forming an annular space between the inner and outer sleeve layers;

wherein the flexible plastics sleeve comprises an air inlet opening at a distal end of the flexible plastics sleeve for coupling the annular space to the conduit, and an appendage opening at a proximal end of the flexible plastics sleeve opposite the distal end for accepting an appendage of a patient within a compartment defined by the inner sleeve layer; and

wherein the annular space defines an annular passage comprising two annular segments for a flow of heated air between the air inlet opening and an air exit opening provided in each annular segment, each air exit opening being provided in the outer sleeve layer proximate the proximal end of the flexible plastics sleeve; and

wherein the flexible plastics sleeve is sealed along longitudinal edges thereof so as to fasten the inner and outer sleeve layers together and define the two annular segments between the inner sleeve layer and the outer sleeve layer.

2. The vasodilation assembly according to claim 1 , wherein the air inlet opening is provided in the outer sleeve layer.

3. The vasodilation assembly according to claim 1 , wherein the inner sleeve layer and the outer sleeve layer are joined at the proximal end of the flexible plastics sleeve.

4. The vasodilation assembly according to claim 1 , wherein the inner sleeve layer and the outer sleeve layer are contiguous and separated by a fold line at the proximal end of the flexible plastics sleeve.

5. The vasodilation assembly according to claim 1 , wherein a most distal extent of the inner sleeve layer is spaced from the air inlet opening at a distal end of the outer sleeve layer so as to maintain a spacing between an appendage located therein and incident heated air conveyed through the air inlet opening.

6. The vasodilation assembly according to claim 1 , wherein a nozzle is provided on the conduit for controlling a distribution of heated air from the heated air supply as it is introduced into the flexible plastics sleeve.

7. The vasodilation assembly according to claim 6 , wherein the nozzle comprises a projecting surface positioned at its end most distal to the conduit.

8. The vasodilation assembly according to claim 7 , wherein one or more openings are formed in the nozzle at a proximal position relative to its projecting surface.

9. The vasodilation assembly according to claim 8 , wherein a baffle member protrudes out of a surface of the nozzle between the projecting surface and its one or more openings.

10. The vasodilation assembly according to claim 1 , wherein the flexible plastics sleeve is rectangular in shape and sealed along longitudinal edges thereof so as to fasten the inner and outer sleeve layers together and define the two annular segments between the inner sleeve layer and the outer sleeve layer.

11. The vasodilation assembly according to claim 1 , wherein the inner and outer sleeve layers are transparent.

12. A flexible plastics sleeve for use as part of the vasodilation assembly of claim 1 , the flexible plastics sleeve comprising:

(i) an inner sleeve layer;

(ii) an outer sleeve layer;

(iii) an air inlet opening formed in the outer sleeve layer at a distal end of the flexible plastics sleeve for coupling to a heated air supply;

(iv) an appendage opening at a proximal end of the flexible plastics sleeve opposite the distal end for accepting an appendage of a patient within a compartment defined by the inner sleeve layer; and

(v) an annular space provided between the inner sleeve layer and the outer sleeve layer defining an annular passage comprising two annular segments for a flow of heated air between the air inlet opening and an air exit opening provided in each annular segment, each air exit opening being provided in the outer sleeve layer proximate the proximal end of the flexible plastics sleeve,

wherein the flexible plastics sleeve is sealed along longitudinal edges thereof so as to fasten the inner and outer sleeve layers together and define the two annular segments between the inner sleeve layer and the outer sleeve layer.

13. The flexible plastics sleeve as claimed in claim 12 , wherein the flexible plastics sleeve is rectangular in shape.

14. The flexible plastics sleeve as claimed in claim 12 , wherein the inner sleeve layer and the outer sleeve layer are formed from a single piece of linear low-density polyethylene (LLDPE) Lay Flat Tubing (LFT).

15. The flexible plastics sleeve as claimed in claim 12 , wherein the inner sleeve layer and the outer sleeve layer are contiguous and separated by a fold line proximate the appendage opening of the flexible plastics sleeve.

16. The flexible plastics sleeve as claimed in claim 12 , wherein distal edges of the inner sleeve layer lying furthest from the appendage opening are sealed together to provide the compartment defined by the inner sleeve layer.

17. The flexible plastics sleeve as claimed in claim 12 , wherein the air inlet opening is formed in the outer sleeve layer at a distal end thereof and is smaller than the appendage opening formed at the opposite proximal end.

18. The flexible plastics sleeve as claimed in claim 13 , wherein a linear or non-linear tapered region is formed proximate the air inlet opening by sealing together opposite surfaces of the outer sleeve layer along two lines between each of its longitudinal edges and its lateral edge.

19. The flexible plastics sleeve according to claim 12 , wherein the inner and outer sleeve layers are transparent.