Intra-arterial lines (arterial line)
Cannulation of a peripheral artery, allows beat-to-beat monitoring of the arterial blood pressure. In addition, arterial blood samples can be taken from the arterial line.
|You should NEVER inject drugs into an arterial line!!|
Many arteries can be used, though never the carotid. The common arteries used are radial and dorsalis pedis. The femoral site is useful in shock; there is no increased risk of sepsis compared to other sites. Cannulation of any artery can lead to vasospasm, embolisation or thrombosis resulting in distal ischaemia. This is of particular concern in sites without collateral circulation (e.g. brachial artery).
Different arterial lines exist with different sizes, lengths and insertion techniques. Radial lines are usually 20G and about 5 – 8 cm long. Insertion is often using the Seldinger technique.
Arterial waveform analysis (pulse contour analysis) is being used increasingly as a means of measuring cardiac output. This requires a specific arterial line (e.g. an arterial line with a thermistor for temperature measurement when using the PICCO system).
Risk / benefit analysis means that most contra-indications are relative. The main ones are local sepsis and coagulopathy.
Failure, disconnection and bleeding, thrombosis, ischemia, haematoma, infection, aneurysm, and inadvertent injection of irritant drugs.