Drawing P.T./INR on Catheter patients

  1. Hello,

    We draw our monthly and midmonthly labs from the arterial lumen of CVC patients and normally first withdraw the indwelling heparin of course- at least 3ml- 5ml
    There has been a debate as to whether the P.T./INR would be accurate anyway if drawn the same way or if a peripheral stick should be done. My latest instructions are get the pt on the maching and draw from the arterial port on the blood tubing---any opinions?

    thanks anyone

    Susan
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  2. 11 Comments

  3. by   happybunny1970
    For PT/INR we have to do a peripheral stick before anything else (aside from maybe patient assessment). We don't even touch the catheter until that's done.
  4. by   steelcityrn
    I have had to collect the inr via a port with the m.d.'s request(would pull it off last). Most of the time it is peripheral to be sure the inr is accurate.
  5. by   raihan
    u can via arterial port.
  6. by   DeLana_RN
    Quote from sueinga
    Hello,

    We draw our monthly and midmonthly labs from the arterial lumen of CVC patients and normally first withdraw the indwelling heparin of course- at least 3ml- 5ml
    There has been a debate as to whether the P.T./INR would be accurate anyway if drawn the same way or if a peripheral stick should be done. My latest instructions are get the pt on the maching and draw from the arterial port on the blood tubing---any opinions?

    thanks anyone

    Susan
    Draw it from the blood tubing once the pt is on? And has received heparin*? How could this be accurate?

    When I worked in a clinic, we of course always withdrew the indwelling heparin first (3 cc syringe); after that, we drew every other lab; then we withdrew an additional 30 cc of blood in 3 10-cc syringes; after that, we drew our PT/INR tube. Finally, we reinfused the 30 cc of blood into the pt. Yes, it's a lot to keep up with (having to keep the syringes with the blood sterile, of course), but was considered to give accurate results.

    HTH,

    DeLana

    *And if the pt hasn't received the loading dose of heparin, then s/he hasn't been properly heparinized before tx! Not trying to state the obvious, just to make a point.
    Last edit by DeLana_RN on Oct 15, '07
  7. by   Hoping to seaya
    Of course depends on your facilities policy towards reuse, but in a recent acute setting, I believe received accurate PT/INR by withdrawing heparin from the catheter per normal, ie 2-3 cc, ascertaining patency of catheter by "exercising" each lumin with 10 cc syringe, drawing other labs, then drawing PT/INR after patient on machine for 10 minutes.

    We used very little heparin with treatments, even those getting "normal heparin" only recieved 2000 ml loading and hourly 1000 till last hour. Reuse in this scenario is not an issue.

    Hope this is helpful.
  8. by   Dialysis RN1
    if you do a web search, I am positive you will find studys that Heparin actually adhears to the lumen of the catheter indicating that drawing clotting times from the catheter would not be a good idea. as for us we have peripherals done. I would hate to decrease a coumadin dose based on a skewed result no matter how small the deviation.
  9. by   PLTSGT
    In my clinic, we do not have a cocrete procedure as to how to draw blood for PT/INR.

    I think these are all great comments and suggestions! Something for our weekly homeroom moot.
  10. by   GeauxNursing
    our nurses draw peripherally first. not from the cath.
  11. by   PLTSGT
    Does your facility have a standing order that if the patient has a catheter that you must draw peripherally?
  12. by   kmcourt66
    In our dialysis unit we aspirate 5cc from both ports of catheter, draw any other lab we need then hook up arterial catheter let the blood run round and before hooking up venous port draw PT/INR from arterial lumen from blood line then hook them up and instilled the heparin load in the venous lumen. results are never crazy that way. but every unit has their own way to do things.
  13. by   mmurphy
    our units draw PT/INR's from cath patiens this way.

    We place the patient on the machine after aspirating 5-10ml of blood from each cath. lumen. We then flush the lumen with NSS and begin the dialysis. We then withold the heparin oading dose for 10 minutes at the beginning of the treatment. After 10 minutes, we draw the PT/INR or PRR from the arterial line. After the blood is drawn we begin give the heaprin loading dose and begin the infusion as ordered. This sems to work for us. However, the only way to get an accurate PT?PTT froma cath patient would be to do a peripherdraw. Our patients go through enough. And this procedure of described above seems to be a fair compromise. If we get a questionable result, we then do a peripheral stick for the PT/PTT pre dilysis.

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