I'm curious as to why this would happen. This morning I was supposed to draw blood from a PICC line for labs. The patient let me know that the nurses the last few days have not gotten a return, so lab has been drawing his blood the last few days. Sure enough, neither port, medication nor blood, gave me a return, but flushed well and fluids ran perfectly well into the line.
I went to draw blood on my next pt with a PICC. I got no return from the red port, but got a good return from the other one.
I feel dumb asking. What is going on here? Other than in scenario #1, the PICC not being in correct placement, yikes, what are the possibilities for this?
Is it simply the beginning of clogging and thus will, for the time being, flush thin fluids but not thick fluids like blood? On both patients, I did have to push hard to flush.
However, an access RN once told me that some types of leur locks make it feel like you are meeting with a lot of resistance, but that it's normal and perfectly patent.
Yes, when one is infusing, use no less than a 10cc syringe barrel to ascertain patency. Then, once patency has been confirmed, use the appropriate size syringe to give the intended medication. However, upon aspiration for labs, the opposite is true.
Flying Scott.... I must disagree totally with you here. RuthB is correct. When withdrawing from an IV catheter, smaller syringes exert less negative pressure and will often yield you a blood return, while the 10 cc syringes will not. A 3 cc syringe as less surface area and usually won't collapse an IV catheter like a 10 cc syringe will do with withdrawal.
The only thing that's opposite about withdrawing vs infusing is that you're creating negative instead of positive pressure, the physics that determine how the weight applied to the plunger compared to the surface area of the plunger produce a higher or lower PSI are the same.
One pound of pressure applied to a plunger with a surface area of 0.25 square inches produces 4 PSI, while one pound of pressure applied to a plunger with a surface are of 1 square inch produces 1 PSI. The relationship to amount of pressure is the same, it's just whether that is positive or negative pressure that is different between the two.
Whether you're infusing or withdrawing, the peak pressure in the lumen can actually be higher with a 10ml syringe just due to the volume, even though it will take more mass applied to the plunger to produce that peak pressure. If a lumen is not able to relieve a pressure buildup faster than it is created, pressure will build, the more volume that can be either infused or withdrawn, the higher the potential peak pressure, it just takes more effort to create that higher peak pressure with a 10 ml syringe. Again, these principles don't change whether you're talking about infusing or withdrawing.
Bottom line is that you can pull back on a ten cc syringe and because of its surface area/suction power per se', collapse the IV catheter and not get your blood draw completed. So, when withdrawing, use a 5 cc or 3 cc to grab that lab.
Bottom line is that you can pull back on a ten cc syringe and because of its surface area/suction power per se', collapse the IV catheter and not get your blood draw completed. So, when withdrawing, use a 5 cc or 3 cc to grab that lab.
I have been taught the complete opposite by multiple different sources over the past number of years (nursing school instructors, preceptor, our hospital PICC presentation done by the infusion nurses, and pretty sure it's even in our hospital policy...). All these sources taught using any smaller than a 10cc is a HUGE no-no and can actually rupture or tear the line. I am going to see if I can find articles to back this up and return to post them
The pounds per square inch or the PSI is determined by syringe diameter and the amount of force applied to the plunger. So never use anything smaller than a 10cc syringe for flushes and medication administration. The infusion pressure shouldn't exceed 25 PSI. It's important to avoid shifting or kinking of the catheter. Don't flush against resistance or use excessive force. Partial or complete catheter obstructions may be caused by thrombosis, drug precipitates, or mechanical factors.
Remember that generally the larger the diameter of the barrel of the syringe the lower the PSI. So, for example, in the occluded catheter with five pounds of force applied to the plunger of a 3cc syringe will generate a PSI of 55. The same five pounds of force to a 10cc syringe will generate only 20 PSI.
Quote
When drawing blood or flushing a CVAD, use only a 10 mL syringe or larger to prevent catheter rupture.
Clinicians should use a 10mL (or larger) syringe to avoid excessive pressure and catheter rupture (syringes smaller than 10mL can produce higher pressure in the lumen and rupture the catheter):
- infusion pressure should never exceed 25 psi because pressures higher than that may also damage blood vessels
- a 3mL syringe generates pressure greater than 25 psi, whereas a 10mL syringe generates less than 10 psi.
These citations are appropriate if you are speaking to flushing. What I referred to is aspiration when assessing for a blood return.
You may join this organization for free (researchgate.net), and note the article:
Denise Macklin article in VAD on "whats physicis got to do with it".
Also note one of the top Infusion Nurses info:
"On injection larger syringes generate less intraluminal pressure when compared to the same amount of force applied to a smaller syringe. On aspiration, the opposite is true - larger syringes generate more pressure than smaller ones. think of it this way - the larger syringe has more surface area and therefore the nurse can pull harder thus generating more negative intraluminal pressure. What harm will this do to the catheter? I am not aware of any reports of catheter damage from this. Usually a soft catheter will collapse, obstructing the backflow of blood. But when the negative pressure is relieved, the catheter returns to it usual shape. I am curious to know about the incident if you can share that with us."
These citations are appropriate if you are speaking to flushing. What I referred to is aspiration when assessing for a blood return.
You may join this organization for free (researchgate.net), and note the article:
Denise Macklin article in VAD on "whats physicis got to do with it".
Also note one of the top Infusion Nurses info:
"On injection larger syringes generate less intraluminal pressure when compared to the same amount of force applied to a smaller syringe. On aspiration, the opposite is true - larger syringes generate more pressure than smaller ones. think of it this way - the larger syringe has more surface area and therefore the nurse can pull harder thus generating more negative intraluminal pressure. What harm will this do to the catheter? I am not aware of any reports of catheter damage from this. Usually a soft catheter will collapse, obstructing the backflow of blood. But when the negative pressure is relieved, the catheter returns to it usual shape. I am curious to know about the incident if you can share that with us."
Lynn
Oh okay, very interesting thank you for sharing this! I always thought we couldn't use less than a 10 for any reason!
IVRUS, BSN, RN
1,049 Posts
Yes, when one is infusing, use no less than a 10cc syringe barrel to ascertain patency. Then, once patency has been confirmed, use the appropriate size syringe to give the intended medication. However, upon aspiration for labs, the opposite is true.