LP question

[B-Bone]

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quick question from an anesthesiologist. not looking for flame war, etc, just info that I honestly don't know.

what needle do you all usually use for an LP?

I ask because our ED (as well at least 4-5 others in hospitals I have worked in) routinely uses a 20g quincke. This leads to lots of headaches which frequently present to us for epidural blood patches (thanks for the business, btw!). Is there something about, say, a 25g pencil point needle that makes it difficult to get fluid or check opening pressures or something? I ask this because I routinely use a 25g pencan for spinals and have never had a PDPH from this. Granted I don't drain out 20-30 cc of CSF.
A friend of mine just got an LP for headache a few days ago. I told him to ask the EP to use the smallest needle possible and pencilpoint if available. They said they didn't have it and used a 20g quincke. so far he's got 4 days of nightmare positional headache and he's coming in for EBP tomorrow. Anyway, just looking for the rationale behind this particular needle choice and whether it's common around the country. thanks in advance!

 

[cofcemt]

Just an intern here, but I was taught to use a 22g whitacre (sp?) atraumatic needle instead of the cutting needle.

 

[EC3]

i use 22g but we do not have pencilpoint needles.

Part of the problem though is feeling forced into doing the LP in the first place.

 

[dotcb]

22G standard needle. Have never had a patient return for headache that I am aware of. Have also used the blunt needle, but personally, I prefer the standard needle and haven't had a practice experience to convince me to change.

 

[Cerberus]

Our kits come with a 20ga but I use a 22ga. The only problem with smaller gauge needles is that they get blockage a lot easier than the 20ga (which one would expect). I have had patients where I knew I was in the space and yet was unable to get flow from a 22ga, switched to a 20ga and had no problem.

 

[tkim]

the prepackaged LP kits come with the 20 ga, but most of us grab the 22 ga needles. if we had access to the smaller needles, most of us would be happy to use them.

 

[Tiger26]

i use a 22 gauge pencil-tipped needle

 

[dchristismi]

22 ga in grownups, although I have used 25 ga when I can find them...assuming the patient isn't really fat - but finding them is the catch. As the others point out, the 20s are in the kits. Why is beyond me. Those things are harpoons.

I do use 25 ga in infants. I had to have these special ordered for me.

 

[SoCuteMD]

The one in the kit is a 20G. We have 22G, but have had problems getting fluid out with them previously. I've used the Whitacre needles before, but don't think we have them where I am.

 

[wobit]

22 Whitacre if I can, but I keep the 20 Quincke that comes in the kit close by, in case. Sounds like you should be investigating the folks that make the kits.

 

[Rendar5]

I use a 20g normally, and our kits come with 18g. now that's just wrong. I've treated my share of post-LP headaches, maybe once every few months in residency. Never saw a solid correlation between 20g v. 22g, but then again I never researched it. I will say I've worked with both those sizes and had more problems with flow on the 22's v. the 20's, and a lot more champagne taps with the 20's too, so that's my preference. I've never tried a 25g. I can only imagine how slow a 6cc collectiong would take.

Now that I'm in the community, I haven't treated post-LP headaches yet. Do you guys consult anaesthesia or do you do your own blood patches?

 

[tkim]

I use a 20g normally, and our kits come with 18g. now that's just wrong. I've treated my share of post-LP headaches, maybe once every few months in residency. Never saw a solid correlation between 20g v. 22g, but then again I never researched it. I will say I've worked with both those sizes and had more problems with flow on the 22's v. the 20's, and a lot more champagne taps with the 20's too, so that's my preference. I've never tried a 25g. I can only imagine how slow a 6cc collectiong would take.

Now that I'm in the community, I haven't treated post-LP headaches yet. Do you guys consult anaesthesia or do you do your own blood patches?

Anesthesia. I've never done a blood patch. Have you?

 

[Hamhock]

I

Now that I'm in the community, I haven't treated post-LP headaches yet. Do you guys consult anaesthesia or do you do your own blood patches?

I was kind a procedure monkey in residency and I wouldn't know the first step in a blood patch.

...and I have never heard of an EM-trained doc (without additional training) placing a blood patch.

Does anyone else here know how to do this?

Also, do those of you who use <22g needles for LPs use introducer needles (18g)?

HH

 

[tkim]

I was kind a procedure monkey in residency and I wouldn't know the first step in a blood patch.

...and I have never heard of an EM-trained doc (without additional training) placing a blood patch.

Does anyone else here know how to do this?

Also, do those of you who use <22g needles for LPs use introducer needles (18g)?

HH

I've read how to do one, but never done one.

Those smaller ga needles sometimes bend - especially the non-cutting tips when you try to enter skin, and a recommendation is to nick with scalpel tip prior to needle.

 

[southerndoc]

I'm surprised ABEM/CORD doesn't try to get programs to train residents in doing blood patches. It makes sense that since we do LP's and cause the post-LP headache that we should be able to treat it. Heck, even doing a blood patch with the initial LP would help a lot of patients.

 

[docB]

I had an anesthesiologist ask me this same question almost verbatim a week ago. In fact I had to look to see where the OP is from.

The answer is that the hospital won't buy them for us. He then (kind of aggressively) said we could buy our own or get them from... insert 8 different ways to obtain medical supplies none of which are feasible here.

I'd use the smaller, atraumatics but we keep getting denied.

 

[B-Bone]

Thanks for the info guys. It sounds like most of the time, needle choice is related to availability rather than a specific advantage of larger bore cutting needles.

I bring it up because we see PDPH relatively frequently, probably an average of once or twice a week. About 90% of these are post LP, either from the ED, radiology, or a neurologist. The other 10% are usually related to labor epidurals, either frank wet tap or some occult dural violation that was not noted during placement. No idea what the denominator is for total LP's in our catchment area, so I don't know the rate.

A blood patch is not a difficult procedure per se, and is usually technically easy on most LP patients. It's a bit more challenging on an obese post-partum patient who was wet-tapped because of very difficult placement (usually sitting up), and who now cannot tolerate sitting for the procedure and must be done lateral. The crux of this for us is these patients seem to show up at really inopportune times and whoever consults us (ED, local neurologist, etc) seems to feel that a blood patch is an emergent procedure that cannot wait.

The technical aspects of a blood patch are basically exactly placing an epidural for pain control. Palpate landmarks at the site of dural puncture or within 1 spinal level, prep/drape, skin wheal, identify epidural space by your method of choice (LOR to air/saline, hanging drop, etc), draw 20-30 cc blood (often the most difficult part of the procedure-I occasionally have to place an art line to get blood), inject blood slowly into epidural space until heavy pressure or discomfort is felt in low back/head, lay pt flat for some voodoo number of minutes (30 for me). Some people place an epidural catheter and inject through that (less chance of catheter migration than needle migration), but it takes forever. Where I trained, all blood patches were done under fluoro by anesthesia/pain docs in the pain clinic. That meant no blood patches on nights or weekends ever. No idea how they get away with that one.

Anyway, I've talked to our EP's about this and they say the same thing (i.e. the kit has a 20g quincke). I dropped off a box of 22g whitacres there one day; I think it's still gathering dust. It's gonna take a cultural change to improve things around here. Meantime, I guess it's a few more bucks in our pockets, though I have no idea what it pays. Thanks again for the insight.

 

[B-Bone]

Irony alert: just minutes after my last post, I wet-tapped a parturient with an 18g Tuohy!