Vessel Cannulation

Question 1

Answer 1

Transauricular catheter in rabbit.

Question 2

What are catheters made of? What is an advantage of polyurethrane?

Answer 2

Silicone, polyurethane, polyethylene, and PVC.
Polyurethane can accept an antithrombotic coating that decreases thrombosis

Question 3

What types of catheters cause less trauma and remain patent longer?

Answer 3

Those that soften at body temp and have tapered round openings, as opposed to stiff with a sharp tip.

Question 4

Question 5

How should VAPs be accessed? What can be instilled in the catheter to prevent infection?

Answer 5

Clipping hair and aseptic prep of site.
Instill antibiotic and enzyme solutions. Anticoagulants like heparin, sodium citrate, sodium EDTA, and taurolidine citrate as locking solutions. 50% dextrose can inhibit bacterial growth.

Question 6

Answer 6

Reservoir port similar to a VAP that allows emptying of pump and refilling via SQ injection.

Question 7

Describe osmotic minipumps (Alzet).

Answer 7

Contain a flexible, impermeable reservoir chamber surrounded by a sealed layer containing an osmotic agent, all surrounded by a semipermeable membrane. When in an aqueous environment (SQ, IP), osmotic agent (high concentrated salt) imbibes water at a rate determined by the semipermeable membrane. Imbibed water generates hydrostatic pressure which compresses the flexible reservoir chamber to produce a constant flow of the contained material.
In marmosets, can be placed in an externally worn backpack, allowing easy replacement.