IV Access

Question 1

Describe an over the needle cannula

Answer 1

• Cannula over needle
• Whole set introduced into blood vessel
• Cannula slid off needle
• Relatively stiff

Question 2

Describe a through the needle cannula

Answer 2

• Large insertion needle with cannula passed through

- Used in central veins

Question 3

Describe a Peel away cannula

Answer 3

Place through an over the needle cannula

Question 4

Describe a seldinger cannula

Answer 4

(Over the wire cannula)

• IV cannula
• Wire passed down cannula and vasodilator administered
• Cannula 1 removed and longer and more flexible cannula replaces it

Question 5

Describe the chemical, physical and biological properties of cannula material

Answer 5

Chemical - stable on sterilisation and implantation
Biological - Non irritant, non thrombogenic, resists microbial adhesion
Physical - High tensile strenth, flexible but not compressible

Question 6

Give an example of a material that is good for making cannulas

Answer 6

Silicone elastomes

Question 7

What effect can the shape and sharpness have on the effect of a cannula on the body

Answer 7

Can play a role in reducing endothelial trauma

Rounded Tips preferable to square /bevel ended

Question 8

Describe the placement of a cannula in the ceplallic vein

Answer 8

• Runs down the dorsal aspect of the forelimb
• Comes in laterally
• Start distally and can then move to a higher site if unable to cannulate

Question 9

Describe the placement of a cannula in a saphenious vein

Answer 9

Obvious veins on the caudolateral end of the hind limb - above the hock
- Must be in lateral recumbency (require assistance)

Question 10

Describe the placement of a cannula in the Jugular vein

Answer 10

Dogs - Straight line from thoracic index to jaw
Horses - within jugular groove
(Use for long term cannulation)

Question 11

Describe the placement of a cannula in the Auricular vein

Answer 11

Along the lateral edge of the ear

Question 12

What could be used as a local anaesthetic for cannula placement?

Answer 12

Emla Cream

Question 13

What gauge of cannula would you use for small cats and rabbits?

Answer 13

22 gauge (blue)

Question 14

What gauge cannula would you use for cats and most other animals?

Answer 14

20 Gauge (pink)

Question 15

What gauge needle would you use in dogs over 20kg?

Answer 15

18 gauge (green)

Question 16

Describe the maintenance of cannulas in patients

Answer 16

Check regularly and flush every 6 hrs with heparinised saline
Swab ports prior to injection

Question 17

Describe 6 problems with equine cannulas

Answer 17

Extravasation (leaking of IV fluids into extravascular tissues)
Thrombosis 
Thrombophlebitis (inflammation of vein)
Infection 
Emboli

Question 18

Define Ambulatory infusion

Answer 18

Animal is freely mothin without need for tethe to connect catheter (fitted with jackets)

Question 19

Define biocompatibility

Answer 19

Good toleration of implanted tissues

Question 20

Define biofilm

Answer 20

Coating which develops on implanted materials derived from the animals tissue fluids and cells

Question 21

Define dishecence

Answer 21

Bursting open or splitting along natural or sutured lines

Question 22

Define friction coefficient

Answer 22

Surface coefficient influences how easily a catheter can be inserted into a blood vessel

Question 23

Define cannula septum

Answer 23

The thick polymer diphragm allowing sealing a vascular access