Size matters? (IV question)

[theantichick]

Ok, something came up today that got me to wondering... is there a rationale for using a smaller angiocath than possible when starting an IV on a patient?

I mean, back in my Paramedic days, we didn't start anything smaller than a 16 antecubital and tried really hard to get an 18 in even for hands if we at all could, because we had no clue what kind of fluids the patient would end up needing, and I was taught that blood products needed at least an 18. Ok, so I've since been educated that blood products *can* use a 20, but an 18 is preferable. And I'm not calling for 14 and 16 in regular use.

But.

Last night the nurse knew my pt needed a unit of PBRC and it would be coming on my shift. The existing IV (an 18) she said was leaking, so she put a 20 in so I'd have it for the PBRC. As a new nurse, I asked around (supervisor, other ICU nurse on duty) and the consensus was that if I could get an 18 in, that would be preferable. Pt had decent veins and I had no trouble starting an 18. (I'm in an LTAC ICU)

So, it got me to thinking... the only nurses I have seen routinely use 18's are ICU and ER/Trauma nurses. Everyone else seems married to 20's and 22's. Is there a rationale for using less than an 18 if you can get an 18 in and assuming there's no expectation of administering blood? (I fully recognize there are lots of patients that you're lucky to get a 22 in, and those aren't the ones I'm talking about.) Or is it that the larger angiocaths scare a lot of nurses for some reason?

I've tried to search my references and even Google for it, and haven't found much of any help. All I've really found is that 20 is the minimum for blood, and 18 is preferred.

[Altra, BSN, RN]

I agree that nurses outside of critical care areas seem "married" to 20s & 22s. It's culture, not rationale.

And BTW ... a 20# is not the "minimum" for giving blood products ... otherwise those neonates, pedi patients, patients with renal or chemotherapy hx, or those whose veins just plain stink wouldn't be getting blood through 22s.

[CodeteamB]

Ok, for some purely anecdotal evidence: I recently had a discussion with one of the home IV team nurses at my hospital. She said that for people who are going to have the IV insitu for and extended period (up to 72 hours) and are going to be at home with same she prefers a small gauge in a large vein, as in her experience it is less likely to infiltrate, and less annoying for the patient. She also said that generally these IVs are only for short term abx, and so nothing larger is needed.

So she also works ER and I know she is perfectly capable and likely to start a large IV on our emergency patients, so I think this is an actual well thought out intentional policy. But I think for most it is just a fear of using the larger catheters (I know that was the case for me early in my career, the only time I attempted an 18 was when it was specifically ordered, and I would go for a 22 unless blood was ordered).

Agree with Altra, you can give red cells through smaller IVs than a 20, as it was explained to me by the same nurse as above: "yah think the cells can squeeze through our teeny tiny capillaries but are going to automatically lyse at the sight of a 22?!?" (I love this coworker btw).

[umcRN, BSN, RN]

Well in peds and nicu we use 24's on all our neonates, and they get blood, fluid pushed, abx and whatever else you can put through an IV so it's not "impossible", we are just gentler if we have to be (but if kid is coding we PUSH no matter the size)

[KelRN215, BSN, RN]

I agree that nurses outside of critical care areas seem "married" to 20s & 22s. It's culture, not rationale.

And BTW ... a 20# is not the "minimum" for giving blood products ... otherwise those neonates, pedi patients, patients with renal or chemotherapy hx, or those whose veins just plain stink wouldn't be getting blood through 22s.

Yeah, I've given blood through a 24 gauge before. In kids, sometimes that's all you can get. In the world of pediatrics a 22g is a "big" IV. I don't think I've ever actually seen a 14g or 16g and the 18g's I've seen were all placed by anesthesia. The biggest I've ever placed was a 20g.

[klone, MSN, RN]

I work in OB, and we try to routinely put in 18 gauge, in case the patient has a hemorrhage and needs blood. However, if they are hard stick or their veins are thin we'll go for a 20 simply because it's easier to put into thin veins.

[akulahawkRN, ADN, RN, EMT-P]

Back when I was a paramedic, I used to put 20gauge IV catheters routinely in hands, and 18gauge IV catheters routinely everywhere else. Normally I did not put an IV catheter in larger than a 18gauge simply because the patient typically did not need the flow volumes that are possible with a larger bore catheter.

Normally I base my IV catheter selection decision on how much fluid that patient is going to need over how much time the patient is likely to need it. If my patients needs a lot of fluid quickly, I'm going to choose a larger bore IV catheter. If I simply need access to the vascular system for medication delivery, I am probably going to choose a smaller bore IV catheter.

I suspect that a lot of the fear around small bore IVs and delivery of blood has to do with trying to push blood through a small bore IV, using a pump to accomplish that. While RBCs are very much capable of squeezing through some very small capillaries, I think that they have a problem squeezing through a small bore IV, while under a lot of pressure. If that is the case, they would lyse. I don't think that there would be that big of a problem infusing blood at a slower rate or by gravity, as fast as fluid dynamics will allow. It's just with the smaller bore IVs that your flow rate for the blood would be much much slower than with a larger bore IV.

Most of my experience with IVs has been as a paramedic, but my most recent experience has been in my role as a student nurse, and I have not been allowed yet to start IVs in clinical situations yet.

[meandragonbrett]

Just because you CAN place an 18 doesn't mean we SHOULD.

[evolvingrn, BSN, RN]

have you had an 18 gauge?:) they hurt and often for some time after you take them out. the reason people on the floor don't regularly put them in because they actually have patients that can verbalize their discomfort and a 20 gauge is more than adequate for 200 ml /hour + which is the fastest we run anything. I give blood all the time with 20 gauge and 22 gauge.

[akulahawkRN, ADN, RN, EMT-P]

Oh, believe me, I've had 18gauge IV's. Yes, they do hurt but then again, so do 20gauge IV's. And you're right about placing 20gauge catheters on the floors. If there's no need to run fluids in any faster than 200 mL/hr, then a 20gauge will do quite adequately. You should remember that EMS and the ED is a bit different of an environment than the floor. Heck, I've seen 16's put in hand veins during my OB rotation. Frankly I was quite surprised those actually didn't blow the veins.

If figure that once I'm loosed on the floors with the blessing to start IV's, I'll still make my choices based on needed flow rates. Since 20gauge IV's can handle the slower rates (under 200 mL/hr) easily, I expect to use that size a lot. I'm actually comfortable starting large bore IV's when needed as well as those really small bore IV's when needed.

[IVRUS, BSN, RN]

The flow rate for a 22g is over 2000 cc/hour. And because you work geriatrics, that elderly patient usually will not receive that blood product in any less of a time frame that 3-4 hours secondary to fluid overload potentials... So, yes, a 22 guage will work excellant. Now, if I were needing to get that unit in in a shorter time frame a larger bore would be approriate. Infusion Nurses Society (INS) standards state to always use the smallest gauge, with the shortest length for the prescribed therapy. AABB (American Assoc. of Blood Banks) can also back up that statement.

Your main concern is damage to the smooth TUNICA INTIMA.. these smooth endothelial cells get roughened up with larger bore IV catheter, especially in the peripheral vascular system. One does not have the blood flow in your arms that you do in your central veins.

Now in an emergency setting when crystaloids and colloids are given quickly, then yes, put in a larger bore. If my pediatric patients can get an aliquot of blood through their 26 gauge catheter, why can't an older patient get it via 22g? Of course they can.

[classicdame, MSN, EdD]

size matters sometimes - we all know that it is preferable to use larger bores for blood products and vesicant drugs. What irritates me is not learning to access veins away from the antecubital space (hey! There is an artery there too!), or the small veins in the hand. The arm has juicy access if you learn to go there - and people can still eat and go to the bathroom. When I worked pedi and got patients from ER the first thing we did was place EMLA cream on a vein because the kids all came up with access in the brachial veins in the antecubital space. Of course their little arms stayed clenched which made the access useless.