Performed a DPE recently, mostly to confirm true loss. Obtained CSF through 25g spinal needle. Removed needle to thread catheter and noticed a very slow trickle of CSF out of the Touhy (LOR was to air), maybe 1 drop every few seconds. Is this a normal finding (maybe she had extremely elevated ICP’s, could that be a plausible though extremely unlikely explanation) or was it a wet tap? I doubt it’s normal and assume it was a wet tap, just don’t understand how it happened after the Dural puncture, if the Touhy never moved. A PDPH I guess would definitively answer my question. Thoughts?
CSF from Touhy after DPE - normal or wet tap?
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Arch Guillotti
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Assume wet tap.
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If LOR to air was clear you’re probably fine and it was just a small leak back from the 25g, especially if in sitting position.
I do DPE and CSE regularly in sitting position with LOR to air. This happens to me about 10% of the time and have never had a PDPH. Made me nervous at first but not anymore. Our spinal needles are 27g however, not sure if that changes things..
I do DPE and CSE regularly in sitting position with LOR to air. This happens to me about 10% of the time and have never had a PDPH. Made me nervous at first but not anymore. Our spinal needles are 27g however, not sure if that changes things..
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Did you end up threading the catheter?
D
deleted875186
Could be a dural Knick with toughy ..... if this is a “normal 10% findings” from anecdotal experience as stated above, makes me highly suspicious of the quoted low incidence with DPE and makes me never want to do it routinely.
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Could be...but if it’s a clean loss with air initially and then csf is returned only after the intentional dural puncture and given the effect of gravity on a fluid, makes sense that it could leak somewhere only a couple millimeters away. I’ve threaded the catheter every time and never had an issue with intrathecal placement.
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So you purposely poked a hole in the dura and now you're worried because you got csf leaking out?
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I would have. Throw the catheter in, do a test dose. Worst case, you are intrathecal and remove the catheter to replace it. If she is an exceptionally challenging epidural (one possible reason for a DPE to confirm), then maybe just run the IT catheter, especially if she's farther along in her labor.
D
deleted697127
Was this for labor or CS? A 25g is unnecessary. If you thread the catheter at that spot, do a test dose, and they can move their legs by the time you finish your paperwork, then it’s not intrathecal.
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LOL
It should be no surprise that a bit of CSF is exiting through the Tuohy - I mean, you just saw some CSF exit through the 25g spinal needle, and now that it's out, there's even less resistance for continued flow out of the patient.
If you're worried about a wet tap from the Tuohy and PDPH, probably not. That kind of CSF return isn't subtle. It'll get on your shoes if you aren't quick.
As an aside, I'm not a fan of DPEs for exactly this reason (hey look! an unnecessary hole in the dura!). Just because most of the time you don't see the CSF leaking out the Tuohy like you did doesn't mean the hole isn't still leaking CSF. I suppose confirming an ambiguous LOR by doing the dural puncture isn't unreasonable. It's the "therapeutic DPE" that people claim is superior to an ordinary epidural that I find to be silly.
Thank you, I was hoping to hear from those who perform DPE/CSE's regularly and have more experience with them. I have only performed a few and
this was the first time this has happened.
I started to, but attending saw the fluid and pulled the needle before I could try or troubleshoot.
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Yeah, probably small leak from the 25g or small Nick from the curve of the tuohy.
Correct, but I defer to those with more experience than me. My concern stems from my rudimentary understanding of a key point that was taught to me that DPE's result in improved sacral coverage via the theoretical mechanism of allowing our medication to pass through the dural hole into the CSF. I don't presume to know whether this same hole can allow CSF to leak outwards instead at the significant rate/volume necessary to present as continuous return via my Touhy needle (though the similar rates of PDPH among CSE/DPE and epidurals would make me think that it doesn't).
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This was for labor. What is preferred over a 25g and why?
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I don't do DPEs.
With CSEs and epidurals, I don't do LOR to air. Why would I want to inject air into the epidural space? Am I hoping to get some air around a nerve root and give the patient a patchy epidural? No.
I do LOR to saline with a bubble of air at the back of the syringe for its tactile benefits, so any leak back I assume is saline.
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I’d thread the catheter in this scenario and check if intrathecal. Most likely the tuohy is in the epidural space. I see benefit to DPE but even more to CSE. Stop doing LOR to air.
What in your opinion is the advantage of LOR to saline compared to air? I get less false loss with the latter (though likely just due to being more familiar with it). I barely inject 1/4-1/2 ml of air when I get loss
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i see no benefit to air in the epidural space. And while you think you inject 1/4-1/2 cc my guess is it’s much more.
also subjectively 5ish ccs of saline in the epidural space post-CSE/DPE dilates the space, allows easier passage of the catheter, and I personally see less one-sided epidurals (CSE/DPE also helps here). All just my opinion as an anesthesiologist who does a lot of OB.
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also, there’s nothing air gives you that saline with an air bubble won’t. Especially when it comes to false loss. If you’re a resident you haven’t seen or done enough to know one way or the other. Not trying to be rude with that - just honest.
Thanks for the wisdom! Completely agree with the last statement - I am still inexperienced (only placed a little more than 100 epidurals) and very much respect and value everyone's advice. Early on I tried different combinations of intermittent vs. continuous, plastic vs. glass, and air vs. saline. I settled on intermittent, plastic, air and since have gotten very comfortable with that combination. I have a few additional questions that I would appreciate any and all feedback on:
1) I have been forcing myself to use LOR to saline w/ an air bubble in a glass syringe as many here seem to advocate this combination. An issue I run into is that if I attach the syringe too early (while Touhy is rather shallow), I am able to easily inject saline despite clearly not being in epidural space. When should I be attaching the syringe, only after I think I have engaged any ligament (supraspinous, interspinous, or flavum)? Or only after I think I am in flavum (though can be mushy and this seems like a recipe for a wet tap)? Is it a known issue to be able to easily inject saline into subq or non-flavum ligament, or could it be something as stupid as I don't have my LOR syringe firmly enough attached to the Touhy needle? Air has been a crutch for me because it seems more sensitive as I can simply pop the touhy in to 2-3 cm, starting checking for loss immediately (despite sometimes still being in subQ) without ever getting loss until I am in epidural space. While I am advancing, I try to assess for more tactile feedback (see below).
2) My understanding is that the first change in resistance felt is typically supraspinous ligament (which can be very crunchy, can feel like flavum but touhy will remain floppy) -> followed by lower resistance interspinous ligament -> followed by the final change of increased resistance into "gritty" flavum at which point the touhy should feel embedded and no longer floppy. Sometimes flavum is mushy and you won't feel it. Is my understanding correct?
3) Continuous vs. intermittent technique - how important is this really? This would be my (potentially) 3rd wet tap that I know of. I'm sure I could do better and perhaps switching to continuous would result in less wet taps in the long run. In terms of speed, I typically take 5-10 minutes from putting gloves on to giving the test dose. Is continuous technique really so much better and faster that it is worth pursuing?
Thanks in advance everyone! Attendings where I train don't teach and tend to do things in one style, so you have all been my teachers by proxy via your conversations, and for that I am grateful.
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I once had LOR on a lady at 2.5. She was a doctor so I'm glad I didn't just ram the needle into 3cm+.
I like doing the bounce technique with air on a plastic syringe. I keep bouncing my right thumb on the syringe as my left hand advances the tuohy continuously. It is the fastest for me and on a normal sized patient I can be done with the epidural in a minute. 5-10 minutes as a resident is pretty good. I think the best technique is probably continuous lor with saline but I don't like it as much. Just do your thing and do it well.
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1) I attach the syringe when I feel engaged in the ligamentum flavum. When you attach the syringe the tuohy shouldn’t move. If it does you’re not engaged. As you do more epidurals you’ll get a better feel when you’re engaged and you can go slow and be more careful in the beginning. Like you said if you’re in the sub q or non-ligamentum you’re more likely to get a false loss. I do saline with a bubble but if the patient is on the bigger side I use a larger bubble. Antedoctally
it helps me better appreciate the lor.
3 ) I do feel that continuous is a little bit faster as you’re not taking your hands off the tuohy each time to test for lor. But do whatever you’re comfortable with. At the end of the day the patient only cares if you got it in or not and how many attempts it took. You don’t want to get a wet tap because you’re doing a technique you’re not comfortable with.
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I've tried to find the fabled <2cm LOR, but nothing yet. So far I've gotten like a smidge less than 2.5cm.
We do DPE in Ob pretty regularly; in my training, many attendings use only air for LOR but I do prefer saline with an air bubble and u can understand the difference when u do thoracic epidurals. Also always wondering if u have a wet tap injecting air in the intrathecal space will make a headache worse due to pneumocephalus lol
I always thread the catheter and check with a small syringe for blood or CSF under negative pressure; if u were in the intrathecal space u would get tons of CSF but if it is just a small leak from your intentional dural puncture with the 27G u don’t get much. In any case, I never remove the catheter even if it is intrathecal. Adjust your dosing, let everybody know and move on. Likelihood of getting a PDPH after the intrathecal catheter is removed is less than if u had a wet tap, removed immediately the needle and tried again. Many people do that but I really don’t get it. The data is there and very obvious.
I always thread the catheter and check with a small syringe for blood or CSF under negative pressure; if u were in the intrathecal space u would get tons of CSF but if it is just a small leak from your intentional dural puncture with the 27G u don’t get much. In any case, I never remove the catheter even if it is intrathecal. Adjust your dosing, let everybody know and move on. Likelihood of getting a PDPH after the intrathecal catheter is removed is less than if u had a wet tap, removed immediately the needle and tried again. Many people do that but I really don’t get it. The data is there and very obvious.
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27G for labor - decrease incidence of PDPH
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This is what I do but with saline and a large bubble. Routine cases get the included glass syringe, obese ladies with edema get the plastic one. Advance the touhy with the stylette in place until you enter a ligament then bounce on in. I advance about a mm at a time, hit a couple bounces on the syringe and move on.
Air has been shown to be suboptimal in some articles so I don’t use it. You can use your google-fu to find the articles, or crack chestnut. It’s probably in there.
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I agree with this here. Continuous is a slick move but you have to be comfortable with your needle control. The key is always to take your time and use very small needle movements. Wet taps are literally a game of millimeters
And as said above do what’s comfortable for you. I was trained on air in the syringe so that’s what I’m comfortable doing and my blocks work just fine. I do air on the plastic syringe. I use saline in the glass because I feel the bounce is smoother and I only find myself using the glass if I just forget to open the plastic syringe and just want to get the procedure done.
when you’re comfortable, try different techniques on what would be “easy backs” and not on some obese lady or someone 10 cm and screaming
D
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Wow, lotsa love for air and a plastic syringe. Y’all are a buncha F’in weirdos if you ask me.
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My institution, people mostly do intermittent LOR to air. I experimented with saline and decided I prefer it (plus the potential negatives of air pushed me as well). We also had a resident who did LOR to air and caused pneumoceohalus with a wet tap - almost immediate severe headache.
I then started trying continuous with the saline on the easy skinny OB ladies. It was a little nerve wracking/intimidating at first but I love it now. Continuous with saline + a small bubble is my preference. If I start hitting bone and stuff I switch to intermittent, but most seem to just go in in ~30 seconds.
Edit: forgot to add that, I've tried the plastic syringe a couple times, totally hated it. Maybe just need to get used to it, but not a fan.
I then started trying continuous with the saline on the easy skinny OB ladies. It was a little nerve wracking/intimidating at first but I love it now. Continuous with saline + a small bubble is my preference. If I start hitting bone and stuff I switch to intermittent, but most seem to just go in in ~30 seconds.
Edit: forgot to add that, I've tried the plastic syringe a couple times, totally hated it. Maybe just need to get used to it, but not a fan.
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@propadex i do saline w bubble/glass/continuous. Had an attending in residency show me continuous and I’ve stuck with it ever since. I like knowing my loss occurs the absolute instant I enter the epidural space. There are rare instances I have to advance another mm or 2 to get enough tuohy in the space to pass the catheter.
once in a blue moon I care for a thin parturient who understands the word ‘exercise’ such that her ligament is tough enough that I’m forced to go intermittent advance.
you will, if you pay enough attention to your hands, get to the point where you can feel everything while advancing and know where the epidural space is before you get to it. Not for everyone of course but for the large majority of parturients.
sounds like you’re on the right path by asking the questions and learning here, since your attendings aren’t teaching.
once in a blue moon I care for a thin parturient who understands the word ‘exercise’ such that her ligament is tough enough that I’m forced to go intermittent advance.
you will, if you pay enough attention to your hands, get to the point where you can feel everything while advancing and know where the epidural space is before you get to it. Not for everyone of course but for the large majority of parturients.
sounds like you’re on the right path by asking the questions and learning here, since your attendings aren’t teaching.
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I do continuous and air. More than once I have had saline gum up the internals of our glass LOR syringes and more than once I have seen this cause a wet tap in other trainees. It caused a wet tap for me as well. I do however dilate the space with 4-5cc of saline after LOR, which you could easily argue is wasted motion. But, air feels much more sensitive to me and I can usually get loss in a non-bovine shaped patient in 60 seconds or less so the extra 10 seconds to dilate with saline doesn't add much.
We don't do DPE's at my institution and they don't make much sense to me outside of an extremely difficult epidural. If you're going to access the intrathecal space you might as well use it as far as I'm concerned.
We don't do DPE's at my institution and they don't make much sense to me outside of an extremely difficult epidural. If you're going to access the intrathecal space you might as well use it as far as I'm concerned.
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I have also had the glass syringe stick and also one time the inside fell out. It was extremely irritating. Then again I have also had the pneumocephalus patient which I felt really bad about but only once.
D
deleted697127
I dropped the back out of a glass syringe while setting up my tray the first time i tried using one...at a children’s hospital on a very young patient. Lol. Didn’t realize syringes existed that could just fall apart. Scarred me for life.
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Anecdotally you guys reckon Intermittent/air reduces your risk of wet taps? Wet taps should be less than 1 in 200. Your numbers all show you air/intermittent folk are getting more wet taps than your peers.
Join the saline/continuous master race. Never look back. 1 wet tap in >500. Plus bloody taps are a thing of the past with a blast of 3-4mL to open the space/extricate your needle-tip from any veins.
Do it! You owe yourselves
Join the saline/continuous master race. Never look back. 1 wet tap in >500. Plus bloody taps are a thing of the past with a blast of 3-4mL to open the space/extricate your needle-tip from any veins.
Do it! You owe yourselves
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Continuous all the way. There's no other feeling like suddenly blowing your entire saline load into the epidural space.
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SMH
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Wow. I had to do a double read on this. I thought I was reading a different website.
I think someone, maybe salty had a handy guide to use the epidural bag solution for everything.... you get to the end even faster.
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A fellow minute man I see
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Sir
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I gave the saline method a go. I’ll allow it
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Good stuff on this thread. I disagree with the above however. I think it has more to do with your own mind-muscle connection. I had more wet taps with continuous saline than I have with intermittent air.
I think the debate is similar to MAC vs Miller. Do what works best for you and gets the patient comfortable. Many roads to Dublin.
Also, with intermittent-air, I feel the needle enter the epidural space and just barely tap the syringe to confirm my location. That injects a minimal amount of air. I then flush with saline to ‘dilate’ the space and flush any air that might be there. If I had a wet tap, the syringe would fill with csf before I even tapped on it so I would avoid the dreaded pneumocephalus as well.
D
deleted162650
Key point when using saline in the glass syringe:
You need to make sure there is a micro layer of fluid between the plunger and syringe to prevent sticking. Easiest way to do this is to hold the syringe upright after drawing up the saline, put a finger over the tip and push the plunger forcing liquid between the glass. Having a bubble also allows you to confirm the plunger isn’t sticking (in addition to giving you that bump and squish that feels so good).
I skip this step by using the LOR syringe to inject skin local. The back pressure from injecting through the 25g is enough to get the fluid where you need it.
You need to make sure there is a micro layer of fluid between the plunger and syringe to prevent sticking. Easiest way to do this is to hold the syringe upright after drawing up the saline, put a finger over the tip and push the plunger forcing liquid between the glass. Having a bubble also allows you to confirm the plunger isn’t sticking (in addition to giving you that bump and squish that feels so good).
I skip this step by using the LOR syringe to inject skin local. The back pressure from injecting through the 25g is enough to get the fluid where you need it.
Arch Guillotti
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LOR to air 100% of the time. Saline is for residents
D
deleted875186
As a pain fellow having done lots of epidurals in ancient people with less firm ligaments, air is much more sensitive. Glass syringe is much more sensitive, but all my clinic carries is plastic.
For OB I don’t think it matters, I will say I like continuous technique with saline in OB as it’s the fastest and slickest, dilates the space, never difficulty threading the catheter.
For OB I don’t think it matters, I will say I like continuous technique with saline in OB as it’s the fastest and slickest, dilates the space, never difficulty threading the catheter.
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Did you guys improve epidural ability over time, or were you slick people always slick?
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You need to do a bunch and do them often
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Same. Would do this. Standard L3-4 epidural/CSE with LOR to NS/air bubble. I used a 27ga whitacre. The one time I tapped with a catheter... the catheter was dripping CSF after I threaded it. If it's really intrathecal... put the catheter lower than the puncture. Dripping... high suspicion. Attach alligator... Aspirate.... Free flowing easy aspiration..... yup that's CSF.
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I honestly felt like I was quicker as a CA3 than I am now, because when on OB or pain then we did soo many. In PP I do maybe a handful a month because our hospital is low volume OB so I feel like I'm not as fast just due to the lack of repetition like I had then. I still am quick but just not guns blazing style lol
