Intravenous Cannulation

Question 1

Reasons for IV route

Answer 1

replacement of fluids, electrolytes, proteins and blood products

A route to administer drugs rapidly, precisely and predictably

A route to administer drugs that may not be absorbed using other routes

Induction of anaesthesia

To feed patients who have an inadequate oral intake

Question 2

Reasons for Central Venous cannulation

Answer 2

Central venous pressure (CVP) or pulmonary artery pressure monitoring

When using irritant or vasoactive drugs

Unsuccessful peripheral cannulation

Long term fluid administration

Question 3

Flow rates and colour codes for different cannula

Answer 3

Gauge Colour code Flow rate ml/min

14 orange 250-360

16 grey 130-220

18 green 75-120

20 pink 40-80

22 blue

Question 4

Sites for IV cannulation

Answer 4

Dorsal veins of the hand
Cephalic vein
Basilic vein
Veins of the foot (rare)

Question 5

Equipment needed for IV cannulation

Answer 5

Cannula
An antiseptic cleaning agent
Local anaesthetic (if required)
Sterile fixation dressing
Tourniquet or assistant
Sharp disposal container

Question 6

Complications of IV cannulation

Answer 6

Haematoma formation - usually occurs during cannulation procedure, particularly following multiple attempts or if poor technique. Needle may pass through the vein and puncture the distal vein wall.

Thrombophlebitis – an inflammatory process that leads to blockage of the blood vessel by substances such a s fibrin. It is more likely to occur if the cannula is in place for a long time, the infusion rate is slow, or if high or low pH or irritant drugs are administered.

Extravascular injection – the cannula does not remain in the vein and the substance being administered enters the surrounding tissues. The patient complains of pain on injection and swelling is observed at the time of injection/infusion. Tissue or nerve damage can occur is the drug being administered is irritant to the tissues. Extravascular injection (extravasation) may occur frequently, it is only negligent if it is not detected.

Haemorrhage – much more likely to occur in central or arterial cannulation, particularly if administration set becomes disconnected.
Infection – clean area well before cannulation, use a sterile dressing. Remove cannula if infection is suspected.

You need to be sure that the cannula is in a vein and not in an artery.