The literature indicates that thrombosis occurs in over 40% of arteries catheterized for over 48 hours. However, this is dependent on the vessel used. Most catheters used for chemotherapy delivery pose no problem and will remain patent for the treatment period. However, a thrombus may embolize, causing vascular insufficiency or distal or central embolism (Weinstein and Hagle [265]). When occlusion occurs due to thrombus formation or spasm, blood flow is usually maintained by the collateral circulation until the vessel recovers. Presence of a pulse and the colour of the area should be checked daily or a Doppler flow meter may be used (Yarbro et al. [276]). Any abnormality should be reported to the medical staff and radiologist. The catheter should be removed by the doctor using firm, steady traction, to prevent dislodging any thrombus present. The condition of the patient and the limb/area should be observed carefully at the time that vital signs are measured.

The incidence of these is low and the likelihood of problems occurring can be minimized by gentle handling of the catheter and immobilization of the limb/area as soon as appropriate (Weinstein and Hagle [265]).

The occurrence of these will be evident from elevated liver enzymes. Therefore, monitoring of liver function tests is important. Any elevation is usually transient (Weinstein and Hagle [265]).

The seriousness of an air embolus depends on the siting of the arterial catheter and whether it is a direct route to the carotid artery and so to the brain. Luer‐Lok connections must be used throughout the pathway. These should be checked at regular intervals and continuous flow maintained. Care must be taken when changing equipment to prevent blood loss occurring, or air entering the catheter, for example shutting off the tap and firm clamping, if necessary.

Strict aseptic technique must be maintained for all procedures and manipulations of the arterial catheter (Weinstein and Hagle [265]).

Although these are both rare, they may occur because of incorrect placement of the catheter. If there is any doubt concerning the placement of the catheter, the doctor and radiologist should be notified because extravasation of the medication may lead to ulceration and necrosis (Weinstein and Hagle [265]).