(CVC) Management Guidance - the Royal Cornwall Hospitals Trust ...

In these cases where there is a valve there may be some lag when drawing back and
testing for patency, so be patient.
Some closed systems lack a clamp as it is not required. So therefore an open system
may require a Heparin lock which must be prescribed as above.
8.4 Locking
The lock is what is intentionally left in the line to keep it patent. Sometimes this is
done with Heparin. It is important to note that Heparin is never to be used to flush
the line and the amount of lock should only be that of the line in mLs. This amount
depends on line length and if indicated this should be in the care plan and prescribed
Always attempt to aspirate any Heparin lock before use of the line, discuss with
consultant whether Heparin can be flushed into patient when aspiration is not
possible. The rationale for Heparin use should come from a consultant who would
have considered the risk of Heparin Induced Thrombocytopenia (HIT).
A flush will clear the line. When using a saline flush only, this acts as the lock
providing the clamp is applied during the last 1-2mLs under positive pressure.
9 Blood Sampling from a Central Venous Catheter (SOP 3)
Blood collection procedure applies for all sampling and the PCH policy must be adhered to
whether peripheral or CVC. Sampling from a central line must only be performed when no
other access is available or appropriate.
This must only be undertaken by practitioners who have been assessed as competent to
undertake the procedure.
In adults, the Vacutainer system must be used using ANTT.
All infusions via the line to be used must be stopped for 15 minutes before sampling. The
first 5mLs of blood must be withdrawn (using blood bottle) and discarded (except for blood
cultures).
The adapter needle (blue) must be attached for Vacutainer use.
On completion flush with at least 10mL Sodium Chloride 0.9% (unless specified otherwise) is
required to keep the line patent using the previous technique. (Refer to SOP3 in this
document)
10 CVC problems
10.1 Occlusions
Occlusion rates within CVC’s are low, but it is still the most common non-infectious
complication. Signs of a catheter occlusion include:
Inability to flush
Inability to aspirate ‘lock’ or withdraw blood although ‘flushing’ may be possible
Sluggish or intermittent free flow of fluids
If the CVC is occluded try:
Un-kink the line
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