Pathophysiology: fibrin tracts consistently form around catheters, sometimes within 24 hours of insertion, creating a potential portal for venous air entry after catheter removal (2).

Indications (3):

• catheter-related infection,
• persistent catheter occlusion,
• catheter-related thrombus,
• damaged catheter,
• the end of treatment.

Treatment:

• Removal of a skin-tunnelled catheter requires local anaesthetic and minor surgical cut-down to remove the cuff if the catheter has been in situ for more than approximately 3 weeks (3).
• The patient should lie down to avoid air embolus (1,3).
• Simple traction can remove the catheter and cuff in catheters, which have been in less than three weeks. Gentle traction can be attempted, but if difficulty is encountered it is important to stop prior to the catheter breaking (3).
• The platelet count should be >50 G/l and the INR <1.5. Ideally, 12 h should have elapsed after prophylactic low molecular weight heparin, and 18 h after a therapeutic dose (1,3).
• Use of a local anaesthetic agent containing epinephrine (1:200 000) may be helpful in the presence of thrombocytopenia and deranged clotting, to minimize local bleeding. A small incision (2 cm should be adequate) is made alongside the cuff and blunt dissection used to free the cuff and avoid catheter damage prior to removal. If the cuff is at the exit site it can be removed by enlarging the exit site wound (3). The intravascular portion should be removed safely prior to cutting the catheter (4).
• If the catheter tip is sheared off during removal, it is likely to embolize into the right heart or pulmonary artery and will require urgent retrieval by vascular radiologists using a snare, under fluoroscopic guidance (4). This kind of complication of central venous catheter removal occurs in up to 2.1% (4). Internal repair of a damaged catheter is no longer recommended because of risk of infection and/or air embolus. External repairs to damaged catheters can be performed using kits provided by the manufacturers (3).

References:

1. Gefahr einer Luftembolie nach Entfernung eines ZVKs. Quick-Alert(R). 2012;Nr. 27 (V1): pdf.
   
2. Venous air embolism associated with removal of central venous catheter. Br Med J. 1992;305:171-172: pdf.
3. Guidelines on the insertion and management of central venous access devices in adults. Int Jnl Lab Hem. 2007;29:261-278: full text | pdf.
   
4. Long-term central venous access. British Journal of Anaesthesia. 2004;92:722–734: full text | pdf.