What is your policy/procedure for drawing blood for PTT from Central line....

globalRN · Feb 6, 2004

off the top of my head:

IF heparin is infusing through the central line, the line that doesn't infuse heparin should be used but probably only after drawing off at least 20ccs of blood before the PTT is collected.

Even then the result may not be accurate.

The most accurate is a regular stick for PTT.

We used to do PT/PTT on central line patients with heparin used for line patency not for anti-coagulation therapy.

Even after drawing off 20 ccs of blood first, the PTT would often be way off. Then we would just do a peripheral stick if we had already tried the non-painful route first.

If you have a patient getting heparin anti-coagulation tx, I would definitely want an accurate PTT, if you are going to titrate the heparin to the results.

In hematology, we are seeing a lot less heparin drips with the increased use of LMWH.

bwalston · Feb 6, 2004

Originally posted by nursenatalie
When heparin is infusing...we have been debating this and are finding a lot of conflicting information...How do you do it?

Our hospital policy is that PT/PTTs are not to be drawn from any line. In some rare instances we have had docs request that it come from a line, but not often. If we can't get a venus stick, we will do an arterial rather than use a line draw.

kc ccurn · Feb 7, 2004

We hold our drip for at least 5 minutes before drawing the labs. If at all possible we use a port other than the one infusing the heparin. If that isn't possible we use the heparin line, with a 10cc waste.

Gompers, BSN, RN · Feb 7, 2004

Very curious about this thread, as I work in NICU and we always draw coags via an arterial line if one is available. We draw back very small amounts of blood (0.5-3cc depending on the type of line) until the port is clear of any IV fluid, and then we take our sample. I don't remember ever comparing these samples to ones drawn peripherally at the same time.

How much heparin do you run in adult TKO lines? We use 2u/cc, which is a standard bag from pharmacy so I assume we're all in the same boat? We only run our TKO art lines at 0.3-1.0cc/hr. Do you suppose that makes a difference?

I wonder if we are allowed to do it because we only transfuse according to the fibrinogen level. Newborn coags are different than adult levels (I believe the PTT can be 3 times the adult value) but still, I'm concerned now!

nursenatalie, ADN, RN · Sep 27, 2004

Very curious about this thread, as I work in NICU and we always draw coags via an arterial line if one is available. We draw back very small amounts of blood (0.5-3cc depending on the type of line) until the port is clear of any IV fluid, and then we take our sample. I don't remember ever comparing these samples to ones drawn peripherally at the same time.
How much heparin do you run in adult TKO lines? We use 2u/cc, which is a standard bag from pharmacy so I assume we're all in the same boat? We only run our TKO art lines at 0.3-1.0cc/hr. Do you suppose that makes a difference?
I wonder if we are allowed to do it because we only transfuse according to the fibrinogen level. Newborn coags are different than adult levels (I believe the PTT can be 3 times the adult value) but still, I'm concerned now!

Our heparin for heparin drips is fifty units per milliliter, sounds like apples and oranges

Pediatric Critical Care Columnist · Sep 28, 2004

Our heparinized art lines are mixed 1:1 for kids over 10 kg, and 2:1 for kids under; all our CVP lines are 1:1. We draw our usual volume of discard blood (about 2-3 ml) then our sample. Our lab will then Hepzyme the specimen to neutralize the heparin before running the test. We have special labels for these specimens and the lab will not run the Hepzyme unless the labels are on the tube and the requisition, and that it's been signed by the collector.

talaxandra · Sep 28, 2004

We run heparin at 50units/ml, always take bloods from a central line if there's one in situ (except cultures) - turn infusion off, discard 10ml then take specimen. A couple of times the result's come back high, and the lab have accused us of sending them the discard sample, but peripheral bloods have come back with a similar reading, which makes me think this technique is fine.

bluesky, BSN, RN · Oct 1, 2004

We draw them from the art line.

zambezi, BSN, RN · Oct 1, 2004

For PT/PTTs we can draw from an arterial line after a waste. Any other central line or peripheral iv it is not policy to draw from...must be a stick. ouch.

Per our policy we can draw from aline but can't do any other blood draws through central lines-triple lumens, cordis', piccs, etc-

gizelda196 · Oct 1, 2004

I shut off all fluids, flush all ports,lock 2, draw discard a red top,draw blue, flush, resume drips. If pt cannot tolerate any drip comming off for a minute while Ii do this than I go right for the ac.

But now I am curious to see if we have a policy on this. Ill look when I get to work tommorrow.....

mattsmom81 · Oct 1, 2004

Good topic. Seems like in practice heparin might be adhering to the wall of the catheter or something despite our best efforts. I frequently will get an off PTT that I don't believe, and I have to try to stick the patient. I prefer a peripheral stick for PTT but sometimes we don't have much to stick, do we.

Some hospitals don't have a vamp setup so we're wasting a lot of blood the patient may need too, wasting from a CVC . Nice if we have an aline with a vamp setup.

The lab asks on our req if the patient is on anticoagulants, which makes me wonder if they DO use Hepzyme, but still my PTT's are frequently way off, it seems.

This would probably make a great study. :)