What is the best practice around infusing medications via CVAD if unable to aspirate blood???

Sylvia, In Calgary, we have an algorithm, approved by the Infectious Disease physicians that allows us to:
1) attempt a normal saline flush, monitoring the client for any adverse effects (S&S of hydrothorax or extravasation/tissue induration). 2) try again for blood flash after the initial flush, using a second normal saline flush (not for fluid restricted clients)3) if no clinical alerts after 20 mL normal Saline, administer dose as prescribed, notify physician of action.

The other key piece is to use correct technique for attempting blood return with Groshong lines- ensure that you pause for a few seconds after pulling back 1-2 mL on the syringe- this allows the valve to open against negative pressure resistance.

Anyone else have a different protocol?

Best practice guidelines (INS & RNAO) indicate that we should have blood return prior to administering medication and that a catheter without blood return must be assessed further prior to its use to determine the cause/type of occlusion. Refer to The RNAO Best Practice Guideline for Care & Maintenance to Reduce Vascular Access Complications, accessed at (http://www.rnao.org/Page.asp?PageID=924&ContentID=796 (p.34).

The first intervention would be to flush the device with NS & attempt aspiration again (aspirate slowly to reduce the chance of collapsing the catheter. If it’s a valved catheter, stop after the first mL to allow the valve to open). Then rule out a mechanical occlusion (i.e., repositioning, coughing, moving the arm, repositioning the Huber needle if a port…, asking the patient if he hears a rushing sound when flushing the catheter [likely indicating tip malposition]). If the patient has to move his arm to get blood return, this may be due to pinch-off if the patient has a catheter that has been inserted into the subclavian vein and should have a CXR to determine if the catheter is being pinched by the clavicle and first rib.

If there are no signs of mechanical occlusion, the withdrawal occlusion (lack of blood return but able to infuse) is likely due to a fibrin sheath encasing the external portion of the catheter, which acts as a ball-valve. You can infuse but when you aspirate the catheter, the sheath gets drawn into the catheter, thus preventing blood return.

Therefore, the next step would be to administer a solution to break down the sheath. Currently the only approved drug on the market is Cathflo®. Ideally the catheter will be treated with these solutions prior to administration of further medications. Some centers require a CXR prior to administration of Cathflo to rule out catheter tip malposition/pinch-off.

One of the risks of using a catheter without blood return is that the fibrin sheath may be encasing the catheter which causes the infused medication to back track along the outside of the catheter into a smaller vein (depending on the extent of the sheath), rather than into the high flowing SVC. This could then lead to infiltration/extravasation, hence the recommendation against using a catheter without blood return. The RNAO guidelines recommend that “solutions such as irritants, vesicants with a pH less than 5.0 or greater than 9.0 or osmolarity greater than 500 should not be administered through a device where blood return is not obtained because if the device is malpositioned it can result in complications (e.g., infiltration and extravasation)” (p. 70).

The RNAO Best Practice Guidelines do suggest that there may be circumstances where it may be appropriate to use a catheter exhibiting withdrawal occlusion (no blood return), particularly if it is a pH neutral/isotonic/ non-irritant, non-vesicant medication. This requires a risk/benefit analysis with the patient and the healthcare professional & then informed consent. The patient should be aware of the risks of continuing use of the catheter and be aware of signs of complications to report to the healthcare professional and the patient should be assessed for complications during the infusion.

Daphne Broadhurst RN
Desjardins Pharmacy,Ottawa ON

All great tips noted. However, don't forget to x-ray if the Cathflo does not restore patency. Never know where those little buggers will go.....
Cherie Pinkerton
HSC- Winnipeg