Arterial Cannulation

Created on Mon, 06/29/2015 - 16:53
Last updated on Mon, 06/29/2015 - 16:53

Previous Chapter:

Safe sites of arterial cannulation

These guys did a fantastic review in 2002, which looked at published literature about something like 20,000 radial artery cannulations.

  • The risk of major complications was not influenced by the site of puncture.
  • Specifically, the axillary radial and femoral arteries were the most commonly used in the literature.

Key notes from that study:

  • There is no difference in complications when comparing ulnar artery cannulation to radial
  • There is no increased risk with brachial artery cannulation (the worst that happens seems to be a transient paraesthesia)

The arteries to avoid are:

  • Temporal (case report of cerebral thrombosis)
  • Posterior tibial (case report of amputation)
  • Dorsalis Pedis (poor accuracy in hypotension)

Complications of arterial cannulation

The risk of major complications was roughly 1 % for all sites.

THROMBOSIS

The biggest risk factor for this seems to be the relationship of the arterial line diameter to the diameter of the lumen, i.e. the more of the lumen the catheter takes up the more likely a thrombus is to form. It takes up to 75 days to recanalize.

Lesser risk factors are being a female (with narrower arteries), having low cardiac output, having multiple attempts at cannulation and having the catheter stay in for longer than 72 hours. A hematoma at the site of puncture is also a risk factor for occlusion.

INFECTION

The abovementioned study reports that the risk of arterial line related infection increases after 96 hours.
It must be mentioned that this risk is much lower than the risk of central line related infection.
In the abovementioned study, arterial line-related sepsis was found in 0.13% of cases.

In any case, the widely held belief is that this risk of infection can be managed by changing the disposable transducer and fluid lines, instead of the catheter itself. We don't know whether this decreases the risk of infection. However, there is evidence that doing it any more frequently than every 96 hours does nothing to reduce the risk of infection (this is extrapolated from data about IV giving sets in general)

PSEUDOANEURYSM

This is rare, and the risk is is around 0.09 to 0.4%.

EMBOLISM

This is even more rare, but gives rise to the most frightening case reports, bulging hideously with pictures of grossly trashed ischaemic limbs. Air emboli are probably even more frequent than clot or atheroma.

Additionally, various sites have specific unique complications. Femoral artery insertion can cause retroperitoneal hematoma, axillary artery insertion can produce brachial plexopathy, and brachial artery insertion can miss and cause an injury to the median nerve (or damage the delicate vessels which supply it)

In summary, where should I puncture and which catheter should I use?

  • It doesn't matter, whether you pick radial femoral or brachial.
  • The femoral is no more risky than the radial and gives a more accurate reading
  • In the radial artery, one ought to perform the Allen test, even though it has little predictive validity.

 

References

From Bersten and Soni's" Oh's Intensive Care Manual", 6th Edition; plus McGhee and Bridges Monitoring Arterial Blood Pressure: What You May Not Know (Crit Care Nurse April 1, 2002 vol. 22 no. 2 60-79 )

Scheer,Perel and Pfeiffer.Complications and risk factors of peripheral arterial catheters used for haemodynamic monitoring in anaesthesia and intensive care medicine. Crit Care. 2002; 6(3): 199–204.

For those who like hardcore physics, this excellent resource will be an enormous source of amusement. It appears to be a free online textbook of anaesthesia.