Differentiating PICC from CA-DVT

[rkealy, BSN]

when a patient develops swelling in the same arm as a PICC. what is the best method for finding the cause. I understand that an ultrasound can be done to look for a CADVT. I have seen them results that state "Hypoechotic" area or mass noted. My question is what differentiates the PICC from a clot, or is that even possible. My question is based on a patient that had marked swelling in the arm with a picc. The dopplar ultrasound was done and stated the above up that extended into the subclavian. The pt was started on lovenox and the md wanted the picc removed the next day. 18 hours after picc removal pt developed SOB HTN desaturation. due to elevated creat no spiral ct available for r/o PE. Follow up ultrasound done to arm showed no obstructions at all. So the question is was the picc the Hypo echotic structure or did the clot dissolve that quickly?

[Anna Flaxis, BSN, RN]

A positive D-Dimer in addition to the doppler results would confirm a clot. If the D-Dimer is negative, there is no clot.

It's possible that the clot broke loose and traveled to the pulmonary vasculature, causing the PE.

A V/Q scan can be done to r/o PE in those who cannot have IV contrast.

No, the clot would not dissolve that quickly. It takes months for clot lysis to occur, in general.

[psu_213, BSN, RN]

I agree that the clot would not dissolve that quickly, especially given that lovenox does not dissolve the clot.

As for the d-dimer...a negative d-dimer rules out a clot of any sort. A positive d-dimer does not specify a clot at any particular part of the body, just that there is a clot somewhere in the body.

And I also agree...if no CTA of the chest can be done, then go with a VQ scan.

[Anna Flaxis, BSN, RN]

As for the d-dimer...a negative d-dimer rules out a clot of any sort. A positive d-dimer does not specify a clot at any particular part of the body, just that there is a clot somewhere in the body.

Yes, that's true. That's why I stated that the positive D-Dimer in addition to the doppler would confirm a clot. Perhaps I should have been more clear. :-)

[psu_213, BSN, RN]

Yes, that's true. That's why I stated that the positive D-Dimer in addition to the doppler would confirm a clot. Perhaps I should have been more clear. :-)

No, what you said was fine. I just wanted to emphasize the D-dimer part...the D-dimer can be useful test, but it has lead to many an unnecessary CTA of the chest when a doctor was on a fishing trip and there was no other assessment data suggesting a PE.

[Anna Flaxis, BSN, RN]

Oh, okay, gotcha!

[rkealy, BSN]

Yes...it is "sensitive" but not "specific"...to pull out some fancy statistic jargon

[iluvivt, BSN, RN]

Yes.... you are correct a color Doppler is usually ordered to look for a UAEDVT (upper arm extremity DVT ) vs a CRT (central). With an US any solid echogenic material in a vein is usually a thrombus unless you have some type of catheter in place. The catheters look like bright straight tubes on the longitudinal view.Once any catheter is identified the radiologist can then start looking for any thrombosis. They are a few types and they can be different sizes and can look like an area of bulging along the vein or a thickened linear looking area along the catheter . They can extend into the vein wall causing a back -up as in a partial occlusion or a complete occlusion. So yes you can tell tell the difference between a PICC and a thrombus.

Often with the UAEDVT it the pts symptoms are not too severe we leave them in place and for the CRT we take them out and anticoagulation is ordered. They usually take awhile to dissipate unless they are the small ones near the insertion site of PICCs that we see more often. Did they only do an US of the arm after the PICC was removed? The thrombosis sounds like it was in a central vein and perhaps a piece of that broke off and caused the symptoms. One important thing to consider is size selection of the PICC line relative to vein size. A PICC nurse should not put a Fr size that is too large for the selected vein as this diminishes blood flow around the PICC and can increase risk for thrombosis. .