Malfunction of the catheter, where injection or aspiration has become difficult, or impossible, indicates the catheter may be occluded, and may be related to thrombosis, the effect of drugs administered, or parenteral nutrition.
Occlusion of CVCs can be prevented by proper use of flushing.
Flushing of long-term tunnelled CVCs requires a syringe of at least 10mL.
- They should be flushed with 10ml of 0.9% sodium chloride followed by a heparin solution (1000 international units/ml) for each lumen.
Maintaining the patency of a long-term tunnelled CVCs can be facilitated by locking a catheter. This involves injecting a small volume of liquid while it is not in use. The lock solution prevents clot formation in the catheter itself and at its tip, and also prevents micro-organism colonisation of the catheter.
