Drawing bloods through IV line

[NYCRN16]

I have 2 questions for my fellow nurses. I work in the ER so I often have to start IV's, draw bloods, than repeat more bloods. We are permitted to draw bloods from the heplock during the initial insertion of the IV, but I was told that we are not supposed to draw bloods from the lock after that point. Here are my questions:

1) Is it acceptable practice to draw bloods from an IV lock well after the insertion? Is there any drawbacks to this? (hemolysis, any type of IV fluids/meds given that interfere with results?) If this is acceptable practice, where can I find reputable literature to justify this?

2) What are some tips to prevent hemolysis of Chem 7 specimens? This happens to me very infrequently, but I was wondering if there is anything I should be watching out for to avoid this happening. The only thing I have picked up on that usually causes my specimens to hemolyze is when the flow comes into the tube too slow.

Thank you for your help!

[BarbPick]

The reason you should not redraw bloods from an existing site is due to the cath material it is made from. A few minutes after it has been in the vein, it softens to conform to the vein. It becomes soft and more flexable. You do not want to change that process, and end up with a painful site.

The best way to prevent Hemolosis, is to get the tubes to the lab quickly. The will spin it down asap and the gel will trap the RBC's and they can test the pure plasma for correct lab results. Waiting will cause the breakdown of the RBC's and incorect data.

[NYCRN16]

Thank you for your explanation! I dont draw labs from an existing IV at work, but I was always wondering why we couldnt do this, and nobody could seem to give me a real answer. Thanks again!

[New CCU RN]

Hmm..interesting. We always draw off of hep locks and have absolutely no problem....

[New CCU RN]

I should clarify.. they are saline locks

[nursesearl, BSN, RN]

I do home care and at times we are unable to get the specimen to the lab right away, sometimes more than 2 hours, and I have never had a specimen hemolize. I don't see a problem drawing blood from a saline lock. If it was a hep lock you would have to flush first. For a central line draw you also need a discard tube.

[cjcsoon2bnp, MSN, RN, NP]

I was always told that you risk ruining the line if you draw from it once its been in the vein for a while but if you were going to try then you flush the line with saline and then use a syringe to draw back 3 - 5 mL of discard blood and then draw your blood carefully for your labs. I know that they will attempt to draw from the line in my ER because its a Peds. ER and you want to avoid sticking the kids again if you possibly can but I do know if the nurse tries and thinks that they are going to lose the line then they will just have to stick the kid again. In an adult patient I would probably just stick them again rather than risk losing the line but it depends on the situation.

!Chris

[iluvivt, BSN, RN]

1. Yes!!! it is perfectly acceptable to start an IV and then draw a specimen from it..you just have to follow some guidelines and realize that it may not always work...so of course, have plan B and just do a standard venipunture to obtain your specimen/ Generally, speaking you should not use a PIV after that inital blood draw from it for future blood draws for a variety of reasons. the intent of a PIV is to instill..not withdraw and if used for that purpose you will limit the dwell time...they often do not work well anyway as a blood drawing VAD as the catheter takes up a significant part of the vein and when you apply negative pressure ( say with a syringe) it just will collapse and the blood can be sluggish. It also will increase the pts chance for infection and does not promote vein preservation. Always remember never to draw above an IV site that is infusing...if you have to..shut it off for one full min...and yes one minute is plenty....it really has nothing to do with the catheter material although some catheter material,such as Vialon does soften after it has been in the vein.

2. If you are are getting hemolyzed specimens...you are doing either of 2 things...you are drawing to fast and with too much pressure.or too slow (which makes one pull back hard on the syringe)..this will burst the cells and what was intracellular now becomes extracellular...if your syringe is vibrating as you draw or if is just flying into that tube..slow down the draw...you want a nice even steady flow. Often, the draw is too slow b/c the catheter is taking up the lumen and/or you are in a small vein and are low on the arm and/or in the hand. I know it is a pain but always have several small syringes ready if the flow is sluggish switch to a smaller syringe ..if all else fails just flush the PIV and do a standard draw from the ACF..those veins are much larger and generally draw with ease...try to avoid the temptation of using the ACF for the PIV....as areas of flexion really should be avoided if able..especially the wrist...the wrist accounts for most of the lawsuits related to IV therapy injuries...

3. I see will see what the INS book says but I have read it many times that it is acceptable practice especially in the pediatric population......I do this ALL the time in the ER