Question about 10cc syringes and picc/ports

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Specializes in Med/Surg/Tele/Onc.

Learned something this week. I didn't know you had to use a 10cc syringe to administer meds through a picc or port. I know you have to use them to flush a picc or port.

This is what I heard in school....Always use a 10cc syringe to flush a picc or port because of the pressure. OK, so I took this to mean that a 10cc syringe delivers more pressure, and you need the pressure to really flush and clean the line. I know it takes more physical strenth to push larger syringes. Obviously I was wrong, but my logical brain isn't making sense of this. Pts with peripheral lines will complain that a 10cc flush hurts, but just pushing a 3cc of meds doesn't. There just doesn't seem to be as much pressure behind a 3cc push. I if I push 10ccs into the sink, it sure shoots out harder than if I push a 3 cc into the sink.

So, more than one nurse told me that a 3 cc has more pressure and you risk damaging that actual end of the line. I want to believe them, but like a said, my brain just can't wrap around this. So can anyone tell my why in a way that makes sense?

And how do you drop up really small doses then? Or oddball doses like Solumedrol where you're drawing up 1.28cc or .96cc? I had a lady who was getting .125cc of dilaudid.

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Think it has to do with the diameter, the smaller the diameter the higher the psi generated. Visualize the way artery constriction works, when you want to raise pressure you constrict the diameter, when the body wants to lower pressure it relaxes the vessels. Here is a syringe guide that shows you the different diameters.

http://www.harvardapparatus.com/wcsstore/ConsumerDirect/images/site/hai/techdocs/Syringe%20Selection%20Guide.pdf

Draw up doses in a TB syringe (or whatever smaller and more accurate syringe you have) and put it in a 10 ml flush or syringe. That way you can measure the dose.

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Specializes in Med/Surg/Tele/Onc.

Thanks for the link, but it doesn't help. All plastic syringes have the same PSI according to that chart if I'm reading it correctly.

The blood vessel constriction makes some sense, but I don't think really explains it. The barrel sizes might be different, but the size of the hole where the medicine comes out and the blunt-tipped canula (what we use) is the same on all syringes. The amount of volume being forced through the hole of a 10cc syringe is greater than that of a 3cc syringe therfore creating more pressure through the hole. Or is my logic flawed??

A TB syringe I understand, because ours have needles. But how do you transfer from one syringe to another when you use the plastic canulas?

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Do you have lur lock syringes without needles? We have these, I always use the 10 ml flushes and just put the needle in the head and squirt away. I wasn't looking at the maximum psi but rather at the diameter of the various syringes.

Okay so if you are using the standard 10 ml diameter syringe it doesn't matter how many ml's because the barrel diameter is the same among the sizes. I included a link.

http://catalog.bd.com/ecat/msds/d05/posiflushbrochure.pdf

Even if it narrows at the end it is the force as you press down behind the it. To calculate the pressure generated you look at the lbs of pressure you exert and the diameter of the barrel. Here is a link that calculates the pressure.

http://www.tomfangrow.com/Syringe%20Pressure.html

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Specializes in Med/Surg/Tele/Onc.

OK, the one post from BD explains it. I did know that it was the diameter not the actual valume that made the difference. I just had it backwards I guess. And we have needles, I just don't use them unless I'm giving and IM or SUB Q injection.

And, our facilities policy is to not draw up meds in the pre-filled flushes. (even thought people do it all the time.) We have 10cc bottles of NS and sterile water to use. I was told that on the pre-filled, the gradation marks are on a sticker, not painted on the actual syringe. Therefore they are not accurate. I find it interesting that the BD brochure you posted shows what looks like the same flushes we use, but says they meet the requirements. hmmmm.....

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If that's the policy I would draw it up in a smaller syringe and squirt it in if you're allowed to. Or maybe ask your educator about the syringes you use.

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I have heard this too, in my nursing books and in my hospital policy BUT then why do we have 3 cc Heparin Locks then??? RNs use them all the time to hep lock PICCS!

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Specializes in Neonatal ICU.
I have heard this too, in my nursing books and in my hospital policy BUT then why do we have 3 cc Heparin Locks then??? RNs use them all the time to hep lock PICCS!

All the 3ml Heparin flushes that I have seen contain 3mls in a 10ml-diameter syringe. It will exert the same amount of pressure as a 10ml syringe, even though it smaller from a volume aspect.

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Think of a 10cc syringe like a water hose and a 3cc syringe like a waterpik-which would you prefer to go in your PICC line? pressure-wise.

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See the info below for the purple power PICC. Particularly scroll under "Warnings and Precautions" and then section III.

For the small dose meds, some may be able to be diluted in order to add volume for use of a bigger syringe. Narcotics can be diluted, but as for other meds, probably have to confirm with pharmacy.

http://www.bardaccess.com/powerpicc/clinician-info.php

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Think of a 10cc syringe like a water hose and a 3cc syringe like a waterpik-which would you prefer to go in your PICC line? pressure-wise.

Good analogy. The smaller the diameter, the greater the pressure which can cause damage to the blood vessel over time.

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It is pure physics. Pressure = to a Force divided by an area.

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