I just came off on an ER externship with a preceptor whom I call "The Vein Whisperer." She's the one the other nurses call when they can't get a line in. She taught me a lot and starting IVs doesn't make me nervous anymore. She taught me to always go in with a 18-gauge unless it's completely clearly unreasonable, because you never know when a patient might need to have an MRI with contrast or a blood transfusion, and since those are thicker substances than NS or IVP meds, already having a larger catheter means the patient won't have to get re-stuck. The other day I was starting an IV line as a favor to a different nurse and had all my equipment set up when she walked in the room. She said that I shouldn't use an 18-gauge, I should use a 20-gauge unless the MD has specifically requested otherwise because it's big enough for contrast/blood and it hurts less for the patient.
I'm inclined to go along with my preceptor. I think it's gonna hurt a bit to get an IV start whether it's 18-gauge or 20-gauge, and either way it's only going to hurt for the 5 seconds or so that the needle is in. I wouldn't think the difference between 18 & 20 as far as pain goes would be significant. But I do think there's a big difference between the two when we're talking about the microscopic, as far as having a larger lumen for the blood/contrast to flow through, and decreasing the chances of clogging the catheter. The way my preceptor was talking, it made me think that it was standard to use 18-gauge for blood/contrast, that if we sent someone back with a 20-gauge for a procedure like that, they would automatically get a bigger catheter before the procedure. But she didn't use those words.
So! What do you all do! 18-gauge or 20-gauge? I never had a problem getting the 18-gauges in.
We use 14's and 16's, and sometimes 18s. I work strictly with trauma patients (not medical complaints) so it's a much different treatment modality that we use.
I'm glad to see someone posted the recommendations stating that the smallest gauge in the largest vein is the best thing for the pt. I guess part of the idea is that blood should be able to flow easily around the catheter when it is in place; obviously it's not good if the catheter is wedged so tightly in a vein that it impedes blood flow.
That said, I think that 18g IVs are EASIER to put in in many situations! Really! They feel big and awkward going through the skin.
But, I find it easier to push the needle + catheter into a vein once I see the flash with an 18 than a smaller needle- with the smaller ones I think I am more likely to puncture through the vein, especially with very curvy veins.
Policy is always the guide, though, for your institution!
Specializes in SICU, EMS, Home Health, School Nursing.
I work in an ICU, so generally we try to stick with the bigger gauge IVs. We do have some 14 gauge IVs, but rarely do we use them. Generally we try to stick with either 18 or 20. The only time we will use a 22 is when there is no possible way that we could get anything bigger in them (little 90 year old ladies that are severely dehydrated).
The size you use really needs to depend on what you anticipate the pt needing. Like others have said, if there is any chance of the pt needing blood, fluid boluses, or IV contrast, go with at the very least a 20 gauge.
For blood we can use a 22g, for CT scans radiology asks for a 20g above the wrist. They have a nurse but say she's too busy to start IV's . I've never started an 18g, we don't stock them on the med/surg floor.
What really gets me is when you go to start and IV and the patient tells you "you are going to have to use a butterfly needle" it drives me nuts
I am a vascular access nurse and I totally agree with accessqueen. I rarely use an 18 gauge catheter and I do IV's all day. I see patients wih very poor access and I would never be able to insert an 18 gauge.
ER Nurses always go for the 18g and with good reason.
However, on the floor the standard is to use the smallest guage possible to get the job done, because less chances of complications like infection and infiltration. For the stable patient only needed pain medicine or antibiodics, I use a 22 guage.
Yes, I know the ICU and ER nurses are cringing at that, but that's my story and I'm sticking to it. :)
I found this post and all the answers very interesting. In my 40 years of nursing, I have seen IV theory come and go but one basic always remained: do as little harm to the vein as possible. When I start an IV, I have a few simple goals: choose a site that is comfortable for the patient and not in the way, anchor the IV well so it does not move and irritate the skin and vein, and use the smallest catheter I can get by with in order to prolong the time the site can be used and to cause as little damage to the vein. If I "need" a 14, 16, 18, 20, 22, 24 or a 12, then I put one in. I do not just automatically use any size just because "that's the best and what we always do". I assess the patient, the purpose for the IV, etc. and then, I choose the size. I always think long term on any IV start.
I found this post and all the answers very interesting. In my 40 years of nursing, I have seen IV theory come and go but one basic always remained: do as little harm to the vein as possible. When I start an IV, I have a few simple goals: choose a site that is comfortable for the patient and not in the way, anchor the IV well so it does not move and irritate the skin and vein, and use the smallest catheter I can get by with in order to prolong the time the site can be used and to cause as little damage to the vein. If I "need" a 14, 16, 18, 20, 22, 24 or a 12, then I put one in. I do not just automatically use any size just because "that's the best and what we always do". I assess the patient, the purpose for the IV, etc. and then, I choose the size. I always think long term on any IV start.
"
Yeah that....If the pt comes in with an MI I am going to need 2, 3 or more IVs. I might put in a twin cath, ie 2IV's in one. Trauma might get a 14, 16 if the veins allow. But with the older pt populations one cant say every pt gets an 18 because they might only have 22 or 24 ga veins, and guess what CT is just going to have to live with it.
Infusion Nurses Society guidelines (based on research) state smallest gauge in the largest vein that will do the job. This is because the smaller the cath the less damage to the intima of the vein. Now, of course, you always have to take into consideration the reason for the IV. A 20 gauge is ok for CT. Unless your institution says otherwise. a 22 gauge works for blood. It didn't used to but the newer cath lumens are larger that the older products. If a patient has something abdominal going on, or a surgical candidate, go for a larger size. IF they are at the tail end of the hospitalization, you can go down to a 22 with no problem.
ER Nurse and these are the recommendations we are going with. There is no reason to damage veins, it's the smallest necessary to get the job done. If all you can establish is a 24g it's time for an EJ or central line!
Even in an emergency-if I have veins that are questionable, I'll take 2-20g or 2-22g over no access and extensive bruising due to blown veins. Any access is good access-and I have used a pressure infuser with 20 and 22 g-THEY WORK.
. I've never started an 18g, we don't stock them on the med/surg floor. 
.thumb.jpg.755b83f43c9f3860c778e2fcb2022ecb.jpg){kind=small}
RazorbackRN, BSN, RN
394 Posts
IMO, the bigger the better...but then again I think every pt should have an a-line and a CVL:p