Arterial cannulas are not replaced routinely so frequent and accurate assessment is essential in order to minimize complications. In the event of a spike in temperature and raised inflammatory markers, removal may be considered.

The arterial cannula site must be assessed at regular intervals to check for appropriate labelling of the device, use of the correct flush fluid, and any pain or erythema at the site. The arterial site should (where appropriate) be left exposed to minimize any delay in detecting dislodgement of the device or exsanguination from the artery. There should always be vigilance if the sample taken from the arterial cannula is not within the expected range, and staff must be trained in considering and eliminating any risk of contamination as this may affect blood results, which could in turn determine changes in consequent therapies. The NPSA ([360]) described a number of serious incidents associated with changes in treatment directly related to arterial blood sampling results. These incidents occurred because of the use of inappropriate flush agents, predominantly dextrose; for example, patients had insulin sliding‐scale infusions titrated in response to contaminated samples where blood glucose was abnormally high and not reflective of the patient's actual serum glucose.

The following volumes of blood should be withdrawn and discarded in order to clear 0.9% sodium chloride, old blood and small emboli from the dead space, the cannula and the three‐way tap:

On each shift it is advisable that the following are checked and documented:

Arterial administration sets should be replaced every 24–72 hours, depending on local policy (Daud et al. [104], Loveday et al. [278]).