IV insertion: 20 gauge vs 22 gauge

Fiona59 · Jun 30, 2018

Our GA's are supposed to have an 18. Especially if they're wearing a blood bank band.

We look at the vein and go from there. We've told not to use 22's but guess what? We miss with anything and send them off for anaesthesia to start. They come back with a 22!

We've decided the theatre crew should be grateful we got it.

Wuzzie · Jun 30, 2018

There is no different technique between sizes. It might very well have been that the veins were too small to accept the larger cannula. I know mine won't take a #20 no way no how.

**canoehead, BSN, RN** · Jun 30, 2018

If all you can get is a 22, send them, and let anesthesia use their excellent IV skills to start a bigger one. They can hydrate, and probably have an ultrasound. They definitely have a surgeon that can put in a central line, if necessary.

Night__Owl, BSN, RN · Jun 30, 2018

IME, the hand veins are more likely to have valves that will stop you from threading. You can either remove the needle, attach the flush and try to thread the catheter after flushing the valve open. Or you can push the needle through the valve, which will usually blow the vein a little bit, but will most times allow you to thread the catheter farther into the vein where it isn't blown.

mariaconcetta · Jun 30, 2018

I feel like it's something I'm doing wrong. I do have occasional issues with not being able to thread my 22's also. It may be I'm not seeing the flash soon enough and go in too much.

Thank you you for all your advice

Guest374845 · Jul 1, 2018

The larger the IV, the further back the catheter sits behind the neeedle bevel (we're talking no more than 1mm most of the time, but read on).

If you can visualize it, what can happen is that you're getting a flash upon needle tip/bevel entry into the vein but might be threading the catheter while it hasn't been advanced into the lumen yet. When using a 22, because of the smaller gap between the catheter tip and bevel, both may happen near simultaneously and you're used to it, whereas the 20 might require an extra mm push in after you see a flash.

This isn't necessarily what's going on in your case, but it's plausible and it does happen when going from smaller to larger gauges.

mariaconcetta · Jul 1, 2018

Thanks for that tip,it's possible that's what my mistake is. I did notice when I went to advance, the catheter" bunched up " at the skin insertion site.

Wuzzie · Jul 1, 2018

Thanks for that tip,it's possible that's what my mistake is. I did notice when I went to advance, the catheter" bunched up " at the skin insertion site.

That could be two things. The vein is too small or you aren't through the vessel wall with the cannula. My suspicion is the latter.

Mavrick, BSN, RN · Jul 1, 2018

That could be two things. The vein is too small or you aren't through the vessel wall with the cannula. My suspicion is the latter.

Totally agree. The catheter obviously isn't even in the vein yet if it is "bunching up" on the skin.

mariaconcetta · Jul 1, 2018

That probably is my issue, I need to adjust the amount I advance after getting a flash.

Thanks.

FurBabyMom, MSN, RN · Jul 2, 2018

I agree with the others about valves. That was my problem a lot of the time, when I worked the floor. I learned to avoid areas likely to have a valve or funny bend, etc. Also, the floating the catheter in trick is amazing if you can get it to work. Also - my other tip is that many people try far too steep an angle to get into the vessel. It's more similar to parallel than most people seem to want to try. I had a resident recently look at me like I had four heads with that tip, I told them to try it, s/he did, and miraculously it worked.

Most adult patients get a 18 or 20 gauge IV in pre-op or come from the unit or floor with one. Kids under 12 we generally wait until we've induced anesthesia to get their IVs. Usually the 10-12+ crowd will tolerate the IV. Won't love it, but will tolerate it. If a kid or adult has a line of any kind (PICC, Hickman/Broviac, Port), we'll use that and evaluate another line later. As an OR nurse, we tend to appreciate whatever is working that you all can send the patient with. There's competing thoughts about whether just to bring the patient back to the OR and get access there. Except that anesthesia providers can (depending on the patient, their comorbidities, their planned procedure) possibly run nitrous I feel the OR is more of a stressful situation to unmedicated patients. So much looks so scary and overwhelming to them.

You all are absolutely correct, fluids make a huge difference. Most of the time anesthesia does have access to ultrasound, though that usually a shared resource. Generally, I see anesthesia staff use ultrasound more for difficult arterial line placements or for most central line placements. It may be different elsewhere, but generally anesthesia starts central lines in the OR. I've seen one surgeon start a central line twice, and both times they were able to gain femoral access while anesthesia was at the time unable to get IJ or subclavian access. This is the surgeon who has been known to attempt and get peripheral IVs consistently and to try to get arterial access for ABP monitoring consistently. We've done some creative things like get an EJ placed, induce anesthesia, run some fluids, and then try for peripheral or central access.