iv catheter/needle gauge selection

That Guy, BSN, RN, EMT-B · May 10, 2017

20 and smaller - most people most complaints

18 - possible/potential need for rapid fluids/circle the drain

16 - need fluids NOW

14 - Oh yeah daddy gets to come out and play

IO - I lose my mind because I love them so much

ED_Murse · May 11, 2017

It all depends on the situation. I try and never use 22g unless I absolutely "have" to (because they are useless if you want to infuse a large volume of fluid in a hurry). If someone comes in with a stab wound or gsw then they get a couple of 14/16g wherever veins can be found. Short of that, I tend to use 18g as standard and 20g on hard sticks. I will use the ACF or close enough to it, I find that lines in the hand tend to get dislodged easier.

Lev, MSN, RN, NP · May 12, 2017

how do you know what gauge IV catheter to choose to insert in someone?
i know that the larger the gauge #, the smaller the diameter/thinner the needle, but does anyone have any tips based on pt chief complaint and symptoms? i'm new and not quick at anticipating what future labs/studies a pt may require down the line yet.
when drawing labs off a fresh IV start, to prevent hemolysis of the samples, is there a threshold of gauge to not use to avoid hemolysis? i hear 22G at most for most cases, is that true?
if a pt ends up being admitted to the ICU from the ED, for example, i have read that ICU RNs do not appreciate IVs in the AC bc of alarms going off for pump occlusion when the arms bend. i mean depending on what is available, i may have no other choice, but i want to try to be considerate iahead of time n case a pt does get admitted to another floor from the ED.
does IV access in the AC only matter if the pt is getting a CT scan w/ contrast to r/o PE or are there other scenarios? is there a certain gauge needed? is the AC where they are administering the IV contrast dye?
do IVs have to be restarted in 72 hours anyway at a new site? idk if this just varies by hospital policy.
in case a pt needs a blood transfusion do you need at least a 22G or below?

I work in the emergency department and I usually start off with a 20g IV in most patients. That is what I start with unless it is an elderly person with fragile tiny veins who is not that sick, they may get a 22g IV. I usually try to get an IV in the AC if I can. This is for the purpose of imaging studies (a 20g is preferred for CT with contrast) and since the veins are large it is easy to draw blood for initial bloodwork and for subsequent draws. In the ED lots of labs are drawn. If I have to start a second line on a person with an existing AC line, I will try to get a line somewhere other than the AC, but this is not always possible. If I try once or twice with a 20g IV, then I may grab a 22g if I don't think I can get a 20g. I will use an 18g on patients requiring it for a CT angio chest or CT angio of the brain. Any time you hear angio and it is above the waist you may need a 20/18g IV possibly in the AC or higher, depending on the hospital. I will also use 18g IVs for a sick GI bleed patient who will get multiple units of blood. You can give blood through any sized IV catheter. In the NICU babies are given blood through 24g catheters so why can't adults. However, you cannot give the blood as quickly through a 24g catheter than you can though an 18g catheter. Babies are fragile and get smaller volumes of blood over longer periods of time. At the hospital I used to work at, they did away with the 72 hour limit on IV catheters for those started in house. Those started by EMS had to be replaced in 48 hours I think. Where I currently work, there is an option in Epic to click for why the IV was not restarted and one of the options is "difficult access."

When I first started off putting in IVs, I used a lot of 22s. When I started working in the ED I became very comfortable with 20s. Now, working in my 2nd ED job, I am becoming more and more comfortable putting in 18g IVs. 22s are fine to start with and will be ok for most patients.

Speaking of EMS, most EMS lines are 20g, some are 18g (usually the more sick patients) and rarely I will see a 22. I think they would rather not put a line in and say "we attempted IV access but were unsuccessful" than actually try to stick the patient with a 22g IV.

RNChris1 · May 25, 2017

That is completely true! I am a nurse and a paramedic, when I solely worked as an intercept paramedic, I only used a 20 or smaller for the difficult IV starts... I used an 18 for almost every patient and 16's or 14's for unstable patients or severe trauma... lol, now that I have been working for a while mostly as a RN I use an 18 for my unstable patients and 20's for everyone else ðŸ˜œ Occasionally I still grab a 14 or 16, but that's not all that often!