Temperature-sensitive cannula

• US 20060030824A1
• Filed: 07/15/2005
• Published: 02/09/2006
• Est. Priority Date: 01/17/2003
• Status: Active Grant

• Current Assignee: Roche Diagnostics International AG (Roche Holding AG)
• Original Assignee: Roche Diagnostics International AG (Roche Holding AG)
• Inventors: Hunn, Marcel, Barkhahn, Susanne, Reinmann, Andreas
• Granted Patent: US 7,513,891 B2
• Time in Patent Office: Days
• US Class Current: 604/264
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61M 2025/0064 which become stiffer or softer when heated
• CPC Class Codes: A61M 2205/3606 cooled
• CPC Class Codes: A61M 5/158 Needles for infusions; Accessories therefor, e.g. for inserting infusion needles, or for holding them on the body

Abstract

A cannula, for introduction into a body tissue, the cannula flexible after introduction, and rigid below a critical temperature and flexible above the critical temperature. In a method for the introduction of the cannula into the body tissue, the cannula is cooled to a temperature below the critical temperature and introduced into the body tissue. After being introduced, the cannula is brought to a temperature above the critical temperature by warming and thus becomes flexible.

Claims

1. A cannula, for insertion into body tissue, which is flexible in the inserted state, wherein the cannula is rigid below a temperature range and is flexible above the temperature range.

2. The cannula as claimed in claim 1, wherein the cannula comprises a porous material in which a temperature-sensitive medium is received.

3. The cannula as claimed in claim 1, wherein the temperature range encompasses 37°

C.

4. The cannula as claimed in claim 3, wherein the cannula comprises a porous material in which a temperature-sensitive medium is received.

5. The cannula as claimed in claim 2, wherein the porous material has honeycomb-shaped chambers.

6. The cannula as claimed in claim 1, wherein the cannula comprises a tube and by a sleeve surrounding the tube, a clearance space between the tube and the sleeve and substantially filled with a temperature-sensitive medium.

7. The cannula as claimed in claim 6, wherein the clearance space includes a support material.

8. The cannula as claimed in claim 1, wherein the cannula comprises a tube surrounded by at least one of an absorbent material and a support material.

9. The cannula as claimed in claim 1, the cannula comprising a wall, at least one of a temperature-sensitive medium and a support material received in said wall.

10. The cannula as claimed in claim 9, wherein, below the temperature range, a clearance space is formed between the support material and a wall surface surrounding the latter.

11. The cannula as claimed in claim 7, wherein the support material comprises a fibrous material.

12. The cannula as claimed in claim 1, further comprising tip and a stiffening element adjacent to the tip.

13. A method for inserting a cannula into body tissue, comprising the steps of:

causing the cannula to be rigid prior to inserting the cannula by cooling the cannula to a temperature below a temperature range,

inserting the rigid cannula into the body tissue, and

after inserting the cannula, causing the cannula to be flexible by warming the cannula to a temperature above the temperature range.

14. The method as claimed in claim 13, wherein the cannula comprises a porous material in which a temperature-sensitive medium is received.

15. The method as claimed in claim 13, wherein the cannula is cooled by evaporation of a volatile medium from the cannula.

16. The method as claimed in claim 15, wherein the volatile medium is applied to the cannula in the form of one of a cooling spray and a disinfecting spray.

17. The method as claimed in claim 13, wherein the cannula is cooled by pre-cooling in a refrigerator compartment.

18. The method as claimed in claim 13, wherein, after insertion, the cannula is warmed by the body tissue.

19. The method as claimed in claim 13, wherein the temperature range encompasses 37°

C.