Triple lumen central lines/test question/and flushing

Nurses General Nursing


We had an "On the Spot" quiz at work yesterday. Something new the nurse manager has created. She brings out quizzes a couple of times a month ....and we fill in the blanks...on the spot.

Central Line questions:

Which lumen for infusing blood?

" " " " tpn/lipids?

" " " iv solutions.....d5/ns ?

' " " withdrawing blood for blood draws?

And what to use for flushing the ports? how much? do you use ns or heparinized solution.....

She was referring to a sub-clavian, triple lumen,central line i.v.

All hospitals are not the same on this.

Oddly enough.

What do you do at your hospital?

gwenith, BSN, RN

3,755 Posts

Specializes in ICU.

The distal lumen is of course used for monitoring as for the rest there is little I have seen written but a couple of years ago there was a commercially available video on CVC lines that suggested that the distal lumen be the one for administration of blood and in the case where no monitoring was occuring it should be used for TPN. TPN should be administered through the middle lumen and never the proximal lumen. The rationale for this is that TPN is usually very damaging to tissue and if the CVC line had migrated out the middle and distal lumens were more likely to remain in the vein.

Some hospitals use heparin locks, some n/s flushes Q6H. I don't know of anyone doing hep/saline flushes anymore since they were linked to HITS.

Hope that helps.


213 Posts

what is HITS?

gwenith, BSN, RN

3,755 Posts

Specializes in ICU.

Heparin Induced Thrombocytopenia Syndrome - look it up in the MERCK manual at the bottom of the page. Thier entry is very informative.

neneRN, BSN, RN

642 Posts

Specializes in Emergency, Trauma.

We don't have a specific policy, but in school were taught:

Distal=Diet (tpn),IVF



We do have policies on flushing and this will probably vary for each hospital on exactly how much you're flushing with. We still use Heplock flush for these lines.


104 Articles; 5,349 Posts

Specializes in Gerontological, cardiac, med-surg, peds.

renerian, BSN, RN

5,693 Posts

Specializes in MS Home Health.

Gwenith that is how I was taught.



1 Post

I am interested in your spot quiz. Can I have a copy of the questions that you had to answer on central lines? One of our nurse educators is interested in pursing this. Many thanks.

Jailhouse RN

156 Posts

In most institutions they use the acronym "SASH" for cath maintainence.

S - saline

A - anitbiotic (or ordered medication)

S - saline

H - heparin

This works with most all CV catheters.

Distal port for blood

Middle port for feeds

proximal for drugs


176 Posts

We used distal-mainly for TPN when called for, medial for fluids, proximal for blood. IVF can be ran through all 3 ports if needed. We also set up the distal port with pressure tubing to monitor CVP. Want to be sure to use distal for feedings so it has time to dilute out in the blood before it hits the heart.

passing thru

655 Posts

Also, the proximal and medial ports are 18 gauge.

The distal has a 16 gauge lumen.

Distal is for CVP and blood transfusion.

Proximal for lab draws.

And medial for TPN (feeds) and meds.

Always change the heplock ports daily....

And , always remember there is a real live human on the receiving end of

your flushing.....

Easy does it.

And , be as sterile as possible.


104 Articles; 5,349 Posts

Specializes in Gerontological, cardiac, med-surg, peds.

From Mark Hammerschmidt's site

The ports are described as proximal, medial and distal - these are the reverse of proximal and distal as regards the patient. In other words, the ports are proximal or distal in relation to the site where the line goes into the patient. So the lumen that opens up at the very tip-end of the catheter - that's the distal port, because it opens the farthest away from the insertion point. The medial port is the next one backwards, and the proximal port is the one closest to the skin. Make sure that the team has checked: you should never infuse anything through a port that doesn't have a blood return.

If you use the central line for TPN - which you should! - then that lumen is tied up for good. If the patient becomes critical enough, then you can take the TPN down and use the port for something else, but you can't use the port for TPN again - the patient will need a new line. Policy.

We usually hook up the distal port to the transducer for reading CVP's, because the medial and proximal ports can snuggle up to the vessel wall and give weird waveforms. We also use the distal port for giving blood products, simply because it's big: the distal port is a 16-gauge lumen, while the other two are 18's. So plan a little - always save a port - maybe one of the medial ones - on a newly placed central line for TPN (even if the patient isn't on it yet. They may be soon...)

From another source

At the proximal end of the catheter 3 separate extension tubes are marked with the gauge size and position of the exit part of the lumen - proximal 18G, middle 18G, distal 16G. Recommendations of ruse of lumens are:

Proximal 18G (white) - blood sampling or general access

Middle 18G (blue) - TPN or general access

Distal 16G (brown) - CVP monitor, blood products, general access.

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