Arterial Access

What is it?
Cannulation of a peripheral artery
- allows constant BP monitoring
- repeated ABG sampling

Usually via radial or dorsalis pedis
- avoid femoral and brachial (lack collaterals)
- femoral has sepsis risk

Local sepsis and coagulopathy

Haematoma, thrombosis, distal ischaemia, intimal damage, aneurysm formation, disconnection and injection of irritant drugs.

Test collateral circulation with Allen's Test
Use a 20-22g cannula.
Ensure light, comfort and assistance
Palpate the artery with two fingers
- feel and imagine its course
Insert at 45o
Puncture the artery
- advance guidewire
- railroad the cannula
- check backflow and secure the cannula
Connect transducer and flush

For BP measurement
Connect via a short rigid length to a 3-way tap, flush device and transducer
- zero and calibrate the transducer
- the shape of the wave is important, eg sharp peaked upswing and low dicrotic notched downswing may indicate hypovolaemia.

Care of the line

Connect to a hep saline continuous flush device
- this keeps it patent
- and allows BP measurement without letting blood out into the line.