central line blood sampling

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    I am in the process of updating our P&P for PICC Insertion and Maintenance in the hospital. I have done extensive literature searches regarding blood sampling from central lines. What I have concluded is: 1. don't draw coags from a line that has ever had heparin infused, and 2. dedicate ONE line for tpn/vanco(or med requiring peak/trough)/heparing gtt.--Is this true?? There is mixed statements on this.
    So here is my question(s). Can you draw blood from a closed ended catheter (ie groshong) as long as you dedicate this specific line for blood draws. Or is it acceptable to draw blood from a line infusing something else as long as you vigorously flush using 20 mls of normal saline (extrapulated from literature), and waste 3-5 mls first? Does anyone know if there are national standards or INS guidelines that dictate this practice??
    Can you draw any lab from an open ended central line as long as you flush with normal saline first?
    Can you infuse dilantin into a picc line as long as it is admixed with NS?? without running risk of crystalizing? Our Neurologist says YES! Please help! thank you in advance.
    And...can you draw blood from midlines? :typing?
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  4. 4
    I can answer all these things for you. Please remember that hospitals and health care organizations can and do make their own policies and base these on a variety of things...the law...the current standard of care which is based on a variety of things such as research, published guidelines and Joint Commission requirements...to name a few. Nursing care at least needs to meet the current standard...but can also exceed the standard.

    1 Generally speaking you want to avoid blood draws from a Midline catheter as it is considered a peripheral IV. You need to think of this line as a means to deliver the prescribed therapy (should meet the accepted guidelines for the use of a midline). If you are drawing blood from it repeatedly you will decrease the dwell time and risk clotting it off. I wrote this in our policy as well and have also noticed a huge increase in our dwell times when we just allow the RNs to use it for the IV therapies.

    2. Oh the Dilantin issue and PICC lines...where do I start....first of all we do NOT allow Dilantin to be infused through our PICCs......the ph of Dilantin is 12 ....and it must be given very carefully with NS flush...then the Dilantin...usually push 50 mg over a min...then another NS flush...of by PF with a filter......no matter how carefully you give it through the PICC we still get crystallization (a precipitate) b/c of the length of the PICC some always sticks and then you infuse something else and then it precipitates fast. You will also find that in many Pediatric hospitals they do not allow it either...imagine painstakingly putting in a 2 Fr PICC with your sterile tweezers into your tiny peds patient and coming back the next day to find it occluded...its not a pretty site....years ago I had a hard time convincing nursing of this.....then we kept track of how many times we had to replace PICCs b/c of this...and they eventually believed me...we now ask if MD will switch to Fosphenytoin...even though they do not always do this. I bet that neurologist has not replaced as many PICCs as I have (since 1989) due to crystallization


    3. When you are administering TPN through any Central line...this should be a dedicated line....and that lumen should not be used for blood draws///some hospitals push this and do not allow blood draws from other lumens of that CVC...I find that unnecessary. This of course is to keep the infection risk low,especially the risk for fungal infection. If you have a staggered tip design....use the distal lumen for the TPN


    4 Blood draws...here is the general rule for flushing volumes and discard volumes....you want to flush with a minimum of at least 2x the priming volume of that line and the discard is the same.....Most PICCs have a very small priming volume from 0.5 ml to 1.0 ml...so you can see.......most of flush volumes far exceed the 2 x the priming volume guideline.....so if you want to pre-flush to verify patency and then perform your discard....that is OK...but I think 20 ml is a bit much for a pre-flush...would rather see that as a post flush...and make sure nurses are performing a pulsatile push pause flush especially the final flush.....make sure all IVs infusing through any and all lumens are shut off for one full minute ....YES one FULL minute is enough....if patient is so labile that their medications can not be OFF for one full min....you will have to gain the blood from elsewhere...You do not need to dedicate a lumen for blood draws...if you have two free lumens...you can use either one unless you have a staggered tip design and then you need to use the proximal lumen..these are usually the short term acute care triple lumens that you see...Arrow brand and Edwards brand are designed this ...some nurses like to use the way. You can dedicate a lumen for meds if you like but if you have two free lumens and want to use one for your 1200 med and the other for your 1600 med...that is not a problem...triple luen PICCs usually have a large lumen..that I like to use for the blood draw if available

    5...Yes you can draw blood from any groshong type catheter..whether that be a PICC port or tunneled chest groshong...a pre-flush is very helpful to open the valve


    6. It is not contraindicated to draw peak and trough drug levels or coags from a CVC.....I do it all the time...you just have to make sure you get an adequate discard and NEVER mix up the discard with the specimen....Sme Hospitals may choose to write this in their policy...but the tip of that CVC is in the SVC and the blood volume dumping into that SVC is a large amt and that is where your specimen is coming from...the mistakes I see are nurses not shutting off all IVs for one full minute...not enough discard and nurses doing an improper draw and getting some of the medication into their specimen


    Did I answer all your questions?
    Last edit by iluvivt on Jul 7, '09
    Daliadreamer, birdie1962, MauraRN, and 1 other like this.
  5. 0
    You have been extremely helpful. You are awesome, and thank YOU!
  6. 1
    I am concerned about the drug levels being acurate if drawn from the same lumen that the drug was administered through. I have always been told that it impregnates in the wall of the catheter and it doesn't matter the amount of the dicard or flush you will still have a potential tainted result.
    Please advise
    birdie1962 likes this.
  7. 1
    If the patient is in the ICU and on special infusion ie, vanco, heparin, or any other infusate that can "skew" lab data, we are always careful to label this line as such and draw from a separate line. However, if you know of any data that supports lab results are altered due to "residual" infusate composite on the picc line, I would love to have it! Our manufacturer states no such claim (biased? maybe..) Sometimes, I have patients who return from home infusion therapy and they often have a single lumen, so it becomes necessary to draw from the only line they have.
    birdie1962 likes this.
  8. 1
    Most lab draws that are skewed are b/c of improper technique...a lot of nurses are not aware that they have to shut OFF all the lumens on multi-lumen CVCs and PICCS.......if I had another lumen available I tend to draw from that one.
    birdie1962 likes this.
  9. 0
    In my precepting I paulsated my flush and my preceptor said do not do that. I was told to do it in clinical. Is there a reason for the different oppinions? Also, I removed a CVC and now I am wondering, should I have had my patient hold her breath or do while doing that?
  10. 1
    Hello,

    The push, pause, push, pause technique of flushing is common practice in infusion nursing. It is done to cause a more turbulent flush to better allow the flush solution to clear out the inside of the injection cap and inner lumen of the catheter. The more you are able to keep the catheter and add on devices clear of infusates, blood, and fibrin build up; the better chance you have of avoiding occlusions and extending the dwell time of the catheter.

    Yes, just before removing the catheter tip out of the skin- you instruct the patient to hold their breath or do a moderate Valsalva manuever for a few seconds (better to teach them this before starting the removal procedure, and the patient will be compliant at the right time). The current INS Standards also instruct to apply occlusive ointment (antibiotic or plain sterile petroleum based) to the insertion site as part of your occlusive pressure dressing upon catheter removal. The idea is to prevent an air embolus; even though the chances are slim of this happening with a PICC removal with the arm as the insertion area. If you are talking about a chest (I'd say anywhere on the thorax or abdomen) or neck placed CVC; there are additional air embolism prevention precautions that must be used such as placing the patient in left lateral trendelenberg position. Here's a link to a good article on the subject from MedSurg Nursing titled: "Preventing air embolism when removing CVCs: an evidence-based approach to changing practice"

    Hope this helped answer your questions.
    Last edit by Silverdragon102 on Jul 2, '13 : Reason: TOS
    birdie1962 likes this.
  11. 1
    Quote from finlyone
    In my precepting I paulsated my flush and my preceptor said do not do that. I was told to do it in clinical. Is there a reason for the different oppinions? Also, I removed a CVC and now I am wondering, should I have had my patient hold her breath or do while doing that?
    Yes there are dfferences in opinion... Infusion nurses have been teaching for years to flush using the push-pause, pulsating method. As Alice stated, it was in hopes of clearing the line from blood and fibrin and we hoped to decrease occlusions. With that being said, new schools of thought have emerged which questions that process. One of the reasons for this has to do with Biofilm. Biofilm builds up inside the IV catheter moreso after the first week. Biofilm is made up of microbial organisms and these organisms produce a slime matrix. The fear with turbulent flushing is that it can cause the biofilm to shear off of the inside of the IV catheter and if the patient doesn't have the ability to ward off the "storm" from the bacterial shower, he or she could develop a blood stream infection (BSI).
    No studies have been done regarding the best way to flush, that I know of, so until then, follow the policy of your agency.
    birdie1962 likes this.
  12. 0
    For the most current strategies, off the top of my head; I would direct you to the SHEA Compendium of Strategies to Prevent HAIs... as they relate to CABSIs and prevention, and AVA's SAVE That Line campaign. There are some differing thoughts, and biofilm exists to some degree in every catheter. The idea is to prevent build up of biofilm in the inner lumen as much as possible I believe.

    Alice


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