Size matters? (IV question)

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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.

Specializes in Orthopedic, LTC, STR, Med-Surg, Tele.

I'm partial to 20s. I only reach for 18ga when I see patients with big old honkin' bulgy veins.

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Specializes in burn ICU, SICU, ER, Trauma Rapid Response.
This is a great thread. I really learned a lot. I do work in an ICU, so my thought has always been 18s if possible, if not I'm married to 20s. Only use 22s in desperation. Granted, I do have a lot of GI bleeders and septic patients, but I am definitely going to run my vanco and peripheral amino through smaller gauges now.

*** That's great. In my hospital we (the RRT RN's) have an a-fib protocol. After checking e-lites, replacing them and up to 3 doses if 5-10mg IV Lopressor, if the patient is still in a-fib we will bolus amioderone and start a gtt. Our protocol requires us to place a brand new 22 or 24 ga PIV for the amio. All other non-code amio must be given through central lines. This means that if the surgery residents want to bolus amio they must consult a nurse for a line, or place it themselves. The RRT RNs are the only ones who can run it through the PIV. There isn't any real EBP justification for requiring everybody else to run amio through a central line but the chief surgery has had some bad experiences with amio in infiltrated IVs. We get to run it through PIVs cause she trusts us.

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Specializes in burn ICU, SICU, ER, Trauma Rapid Response.
I'm partial to 20s. I only reach for 18ga when I see patients with big old honkin' bulgy veins.

*** Why?

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I use the smallest needed. Blood goes in just fine in a 22G and if ya think a baby or toddler will take a 20g for blood than you are mistaken. 20g is my most common mostly because is the smallest CT prefers for some studies but again - 22g works well for contrast unless it is for a few tests. Pays to know what the doctor you are serving prefers as well as where they like it. I work ER which they don't care so long as they don't have to do it, PACU nurse and anesthesia docs do have preferences that are good to know.

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Specializes in LTAC, ICU, ER, Informatics.

I hadn't realized the thread had continued and that there was a question about my choice to place a 2nd IV. Here's the way it went down: I remembered being taught you needed an #18 if you were giving blood products so I thought it was odd that the offgoing nurse started a #20 specifically for my PBRC admin. So I asked my co-worker to double-check my recollection and she was under the same impression that we needed an #18. I also asked my charge nurse, who also agreed and told me if I could get an #18 to start the 2nd line and use it for the PRBCs, and if I couldn't to go ahead and use the #20. The patient also had Clinimix running which, if I hadn't started the 2nd line, I'd have had to stop during the blood transfusion, and the patient's nutritional status was beyond poor. So there was more going on than just "the new grad thought she knew better." After the fact I discussed it with the nurse who precepted me through my orientation and my nurse manager - both whom have been ICU nurses for years and years, and both told me the placement of the #18 was appropriate and that if the patients' veins will support it, their go-to is an #18.

I started the thread because I asked several times in nursing school what the guidelines are for what size - knowing that the old paramedic mentality of "bigger is better" probably didn't serve - and never really got an answer other than being told blood products need an #18 if at all possible. In my orientation it hadn't come up because we always had a PICC or midline when we administered blood products.

There's a huge body of knowledge and experience here, and I really appreciate all the comments and information.

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Specializes in NICU, PICU, PACU.

In NICU we give blood products they 26 gauges when that all we have, never had an issue. :)

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Specializes in CICU.

Like so many questions - the answer is "it depends".

Had an instance recently where I had to start a 4th line. I've never personally had more than one IV at a time, multiple ones must stink.

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

Here is what I know........

Peripheral Access Devices

In choosing size, a 22-gauge IV catheter is appropriate for the infusion of peripheral IV fluids and medications in adult patients. A small 24-gauge catheter is appropriate for neonates, pediatric patients, geriatric patients, and patients with small-lumen veins.

IV Catheter Flow Rates

  • 18 gauge: 4,000 mL/hr
  • 20 gauge: 3,500 mL/hr
  • 22 gauge: 2,000 mL/hr
  • 24 gauge: 1,500 mL/hr

A 20-gauge catheter is the most appropriate size catheter for adult blood transfusions, most pre-op patients and patients in labor. However, a 22-gauge catheter can safely infuse packed red blood cells into adults without damage or hemolysis to the red blood cells. A 24-gauge catheter is the most appropriate size for blood transfusions in neonates.

Gauge Selections

  • 18 gauge: massive hemorrhage; major surgery
  • 20 gauge: adult blood transfusions; preop patients; labor patients
  • 22 gauge: routine IV therapy in adult patients; permissible for adult blood transfusions
  • 24 gauge: routine IV therapy and blood transfusions in neonates; infusions in geriatric patients

The problem being in trauma is the anticipation of needing high volume rapid infusion of fluids....so you go large bore and large vein. The current EBP is to use the smallest bore possible to do the "job" effectively. The less trauma to the vein the less likely it is to develop phlebitis....Avoiding the Pitfalls of IV Therapy | CE94-60 > Content
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