Anatomy & Physiology

From the diagram above, the most common places for cannulation include the dorsal aspect of the hand and the cephalic vein in the forearm whereby success rates, pain level and complication rates are similar for both sites.

If having to use the cephalic vein, it is important to avoid the area of the anatomical snuffbox due to the increased risk of inadvertent puncture or cannulation of the distal radial artery.

If available, it is always best to target the larger looking veins that are easy to palpate and where the cannula will not impair the movement of the wrist or elbows.

Sites to avoid when performing cannulation include:

• Anatomical snuffbox
• Arms where there are arterio-venous fistulas (eg in dialysis patients)
• Areas where lymphatic drainage has been affected (eg the arm following axillary surgery)
• Areas of cellulitis or burns
• Small veins in the lower limbs and feet, especially in diabetic patients
• Areas of peripheral vascular disease, varicose veins, venous hypertension, or oedema
• Joint Surfaces