Indications

• Fluids infusions.
• Blood transfusions. 
• I.V Medications

IV infusion

Blood transfusion

Cannulae selection

When considering the choice of cannula attention should be given to the following:

• minimising discomfort to the patient, 
• ensuring good flow rates, 
• cannula should be of the smallest practical size to provide the required fluid regimen but take into account:                                                                                   

                     - the size of vessel cannulated,                                                                              

                     - the time scale of the proposed administration of infusion                                          

                     - the viscosity of the fluid to be infused.

14g

16g

18g

20g

22g

24g

Sizing scale of the French catheter system

Equipment

Pain reduction

• Good technique, skill and vein selection (metabrachial wrist veins are painful)
• Local anaesthetic infiltration (especially for large bore cannulae)
• Topical anaesthesia e.g. EMLA cream or EMLA patches. 

What is EMLA

By the patient having emla applied prior to the procedure (usually 1 hour ahead of procedure), there is a significant opportunity to reduce the pain and distress for patients for a procedure involving a needle (IV cannulation, vaccination, blood testing). 

Watch the photos below on how to apply Emla cream AstraZeneca:

Source: http://www.emla.co.uk/Content/How-to-use-emla.aspx?mid=2 

EMLA cream

EMLA Patch

EMLA cream application: Step 1

EMLA cream application: Step 2

EMLA cream application: Step 3

Infection Control

Asepsis is vital as the skin is breached and a foreign object is introduced into a sterile circulating system. The main sources of microbial contamination are:

Hands should be clean, having been washed prior to the procedure, and an alcohol solution/gel applied to the hands before wearing a pair of gloves.

Gloves will protect your hands against contamination from the patients' blood and will provide some additional protection in the case of a needle-stick injury by wiping some of the contaminating blood from the needle prior the skin puncture.

The puncture site should be wiped with an isopropyl alcohol 70% swab and this should be allowed to dry (for a minimum of 30 seconds) prior to proceeding with venepuncture. This will clean any gross contamination of the patients' skin and will reduce the patients' skin flora at the site of the puncture.

The skin must not be touched or the vein re-palpated once the skin has been cleaned,

Sharps should be immediately disposed of in a sharps container, and no needles should be recapped.

This is to avoid needle-stick injuries to you or others involved in the patient's care, lowering the incidence of blood-borne viral illnesses (In particular Hepatitis B/C and HIV)

Use a no-touch technique for any part of the needle or cannula which is to puncture the patient's skin. 

Technique

1. Inform patient of the procedure
2. Select a suitable vein - e.g. the vein in the forearm or dorsum of the hand
3. Palpate the vessel
4. Apply a tourniquet proximal to the selected site
5. Wear gloves
6. Cleanse skin with an alcohol wipe
7. If required, infiltrate skin over the proposed puncture site with 1 % lignocaine solution
8. Hold patient's hand with your non-dominant hand, using your thumb to keep skin slightly tense, and anchor vein to prevent it rolling
9. Inspect needle tip to ensure cutting edge is smooth and intact. Place cannula needle in line with the direction of the vein, with bevel pointing upwards to reduce tissue trauma
10. At a low angle (10-30 degrees), gripping the cannula, insert the needle through the skin and into the vein, as identified by the flashback of blood into the chamber at the hub of the cannula
11. Once inside the vein advance the needle 2-3mm in parallel motion (10 degrees) to ensure the cannula is also in the vein
12. Either: a- Withdraw the needle stylet (holding the cannula steady) about 5mm to avoid piercing the posterior vein wall, there should be a further flashback of blood along the shaft of the cannula and now advance the cannula into the vein Or b- Slide the cannula over the needle into the vein.
13. Never re-insert the stylet as this can sheer off the end of the cannula and cause an embolus.
14. Release the tourniquet
15. Place a finger over the vein above the tip of the cannula to prevent bleeding as you now remove the needle stylet.
16. Place a luer cap with a valve on the cannula and safely dispose of the needle
17. Flush the cannula with isotonic saline to ensure cannula patency. Proper IV placement is confirmed by a smooth saline flush without evidence of extravasation into the subcutaneous tissues.
18. Cover the insertion site and immobilize the cannula by applying a sterile non-occlusive dressing

Care after insertion

Complications

If Cannulation is unsuccessful do not reinsert stylet into cannula as it may shear off the cannula and lead to catheter embolism.

Chemical irritation from the infusion may cause phlebitis and pain. An acidic pH and high osmolality are particularly likely to cause problems. Dilute solutions appropriately for peripheral administration. Where osmolarity of the solution exceeds 600molmolal avoid peripheral venous administration and give into a central vein. 

The cannula may be blocked from thrombus formation if it is not kept flushed.

Extravasation occurs when cannula pulls out of the vein or becomes partly occluded by venous constriction causing backflow of the infusate through the puncture site into surrounding tissues. The patient may complain of tightness, burning and discomfort around the IV site and there may be swelling and blanching of the tissues.

Treatment is to stop infusion immediately and re-site cannula.

A haematoma is formed when blood leaks into the tissues surrounding the insertion site after failure to penetrate vein properly during insertion, puncture of the posterior wall of vessel or removal of the cannula. Treatment is to apply pressure to puncture site for 3-4 minutes.

Infection: This can cause phlebitis and thrombus formation. It is prevented by good aseptic technique, keeping the dressings clean and not leaving the cannula in for any longer than necessary.

     1- Phlebitis: This is acute inflammation of the intima of the vein. It is caused by mechanical and chemical irritation, or by microscopic particles that may contaminate infusion fluids. Clinically there is erythema over the cannulated vein and surrounding skin and it is warm to touch.

Treatment is to remove the cannula.

     2- Thrombophlebitis: This is acute inflammation of the intima of the vein with the formation of a thrombus.

It is commonly associated with infection at the site of the cannula and may present with raised white cell count, lymphadenopathy and positive blood cultures. There may be pus visible around skin entry site.

Treatment is to remove cannula and commence parenteral antibiotics. 

Nerve Damage

It is also possible for the IV needle to penetrate and injure a nerve, and for bruising and bleeding to irritate a nerve. Nerves are invisible from the skin surface so it is easy to understand how this could happen. If the patient feels a sudden sharp pain radiating along your arm as the IV is inserted, this may be a sign that the needle has come into contact with a nerve.

Removal

Cannulae should not remain in situ for any longer than necessary to reduce the risks of infection. Consideration should be given to re-siting them after 48-72 hours.

When removing the cannulae, pressure should be applied to the site for at least a minute and the site should be occluded with a sterile dressing.