LP Positioning - Lying on side vs. Sitting

[gree0411]

I prefer the sitting position because it's easier to ascertain midline. However, I've been getting conflicting thoughts regarding opening pressures. I've heard some say that opening pressures are only accurate with someone lying on their side and I've heard that sitting up is the way to go.

If there is a more appropriate way, is there a formulation that could be used to measure opening pressure when using the non-appropriate method. Thanks.

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[mikecwru]

I prefer the sitting position because it's easier to ascertain midline. However, I've been getting conflicting thoughts regarding opening pressures. I've heard some say that opening pressures are only accurate with someone lying on their side and I've heard that sitting up is the way to go.

If there is a more appropriate way, is there a formulation that could be used to measure opening pressure when using the non-appropriate method. Thanks.

I usually prefer sitting up. The dogma was always taught that laying down was the only way to get an OP. I doubt it will really make much difference. I glanced over the SAEM abstracts and there was one paper on this very subject. Try doing a lit search on pub med and let us know.

mike

 

[nuke laloosh]

My 2 cents...

Sitting up is easier. Hard to get off midline this way, therefore dealing with just one plane (superior-inferior) instead of two. (Much easier to hit a kidney with pt lying down)

Cavets to easier sitting up...
-Some pt's unable to do this
-Some pt's refuse to give you kyphosis while sitting up, which is the most important part of the whole procedure. Lay them down and have an NA squeeze them into a ball, and you'll get your kyphosis.
-Can't get an opening pressure with pt sitting up (always heard this -- don't know the literature).

If you really need an opening pressure and don't think you'll be able to get the tap with them laying down, then do it sitting up and then lay them down and then get your OP.

My advice -- your going to do at least 100 of these in residency -- just learn to do it both ways.

nl
em pgy-3

 

[BKN]

I usually prefer sitting up. The dogma was always taught that laying down was the only way to get an OP. I doubt it will really make much difference. I glanced over the SAEM abstracts and there was one paper on this very subject. Try doing a lit search on pub med and let us know.

mike

Very good discussion of LP procedure in Roberts and Hedges. The NS guys really want an opening pressure. It's certainly easier to do the procedure sitting up. If you do it in lateral recumbency, make sure you have a pillow between the patients knees, another pillow for the head and the line between the shoulders tangential to the bed. Hips flexed, back pushed out towards operator. Flexion of the neck doesn't help much. Otherwise, the patient is often twisted in such a manner that if you find the midline and angle the needle parallel to the bed, you're actually going off the midline. Also, please find the iliac wing and go cephalad of a line drawn to the spine. I get really tired of resdients trying to a sacral bone biopsy.

Again the chapter in Roberts and Hedges is really complete for indications, technique, lab oreders and interpretation. Recommend it highly.

 

[BKN]

My 2 cents...

(Much easier to hit a kidney with pt lying down)

em pgy-3

How high are you going?

I'll add smething to my last post-one or two interspaces above the iliac wing.

 

[nuke laloosh]

L4-L5, maybe L3-L4

Much easier to hit a kidney with pt lying down

For illustrative purposes only, trying to explain that with pt lying down more challenging to stay midline, as opposed to sitting up where it is virtually impossible to stray.

sheesh

nl
em pgy-3

 

[southerndoc]

(Much easier to hit a kidney with pt lying down)

The saying is that if you've never dropped a lung putting in a subclavian central line, then you haven't placed enough of them.

Is the same true with LP's? If you haven't hit a kidney, you haven't done enough of them? I've done probably 60 LP's and not once have I hit a kidney (or came anywhere close for that matter). I'm nowhere near the kidney when I do LP's. I think I would have a much greater chance of hitting the aorta than the kidney.

 

[nuke laloosh]

Have you dropped a lung on a subclavian? I have. On a real skinny 18yo with great landmarks in the Trauma ICU. That was a sick feeling drawing back nothing but air. Got a cxr to confirm what I already knew (but didn't want to believe).

He was trached/on a vent, and his pressures were starting to drop while setting up for the chest tube, so he got needle decompressed first.

I'm still not sure what happened, I swear his lung must have been wrapped around his clavicle. It's not like I was mucking around in there -- I found my landmarks and headed for the sternal notch and then boom a bunch of air.

So that's one out of about 70-80...I think the quoted risk is about 2%.

And no I've never gotten pee from a spinal needle.

nl
em pgy-3

 

[neglect]

Pee from the LP? If that's even a consideration as you get ready to do it, then call either neuro or fluoro because you're way off.

Also, if you really need an opening pressure (there are only one or two circumstances when its helpful in our post-head CT world - crypto for one, IIH for another) and can only do it sitting, then consider measuring OP from where C1 would be. That'll give an approximation of intracranial pressure. Usually it doesn't matter, triple usually in the ER.

 

[ERMudPhud]

I always do them lying down and rarely (less than once per year) have to ask IR to help when I can't get it. I always measure an opening pressure because a few years ago when I didn't I missed a fulminant pseudotumor on a patient where pseudotumor wasn't even on my differential. So now even if the only thing I think I am ruling out is meningitis I still measure on OP. Yes you can get an OP various ways if you start with them sitting up but it is easier if they are already lying down. I think if you make a point of doing them all lying down early in your training then you will quickly become comfortable with the landmarks, positioning, and approach. I never use the pillows that BKN mentioned mostly because I can never find pillows in our ER and the resulting curve to the spine doesn't seem to throw me off. I do think the key as BKN said is to make sure you are well cephalad of the iliac crest. Most people error on side of going lower. The conus ends at L1 or so and if you miss on your first try going higher is more likely to succeed then lower. L3-4 is certainly more open than L5-S1.

If you don't have fluoro then one trick that has worked for me for real heavy patients is to tape a bunch of paper clips up and down their spine and shoot a lateral spine film with them lying in the fetal position and then mark the clip that is over the L3-4 space. I've also heard of people using U/S to find the spinous processes but I haven't had much luck with that in the real fat ones.

 

[NinerNiner999]

One could argue that a true opening pressure can only be obtained in the lateral decubitus position with the patient's legs extended upon entering the space. I have never heard that sitting is appropriate for OP...

 

[Flopotomist]

Pre-med here, but I was the research coordinator on a study that addressed this question. Here is the link:

http://www.aemj.org/cgi/content/abstract/10/5/492-c

 

[BKN]

Pre-med here, but I was the research coordinator on a study that addressed this question. Here is the link:

http://www.aemj.org/cgi/content/abstract/10/5/492-c

Interesting abstract, I don't find that it was ever published in full. With this kind of rule generation, you really need to see the whole data set, including an error diagram. Also were the the taps done in random order to offset the lowering of pressure by draining fluid in the first tap?

Anyway, sounds intriguing. Need to be peer reviewed and published in full.

 

[roja]

Very good discussion of LP procedure in Roberts and Hedges. The NS guys really want an opening pressure. It's certainly easier to do the procedure sitting up. If you do it in lateral recumbency, make sure you have a pillow between the patients knees, another pillow for the head and the line between the shoulders tangential to the bed. Hips flexed, back pushed out towards operator. Flexion of the neck doesn't help much. Otherwise, the patient is often twisted in such a manner that if you find the midline and angle the needle parallel to the bed, you're actually going off the midline. Also, please find the iliac wing and go cephalad of a line drawn to the spine. I get really tired of resdients trying to a sacral bone biopsy.

Again the chapter in Roberts and Hedges is really complete for indications, technique, lab oreders and interpretation. Recommend it highly.

You have pillows????? that's a really posh hotel.. I mean, hospital you are working in....

I prefer lying down. while I have tried the sitting a few times, I have found the dizziness factor (they often get all quezzzy feeling..) and really getting them to round there back doesn't work so well.

Lying down I can really work with them and don't have to worry about them passing out.

Ultrasound is helpful if you have a hard one....

 

[Flopotomist]

Interesting abstract, I don't find that it was ever published in full. With this kind of rule generation, you really need to see the whole data set, including an error diagram. Also were the the taps done in random order to offset the lowering of pressure by draining fluid in the first tap?

Anyway, sounds intriguing. Need to be peer reviewed and published in full.

Unfortunately, the PI is deceased, and the PA student that was working with him is gone now. (hmm..the raw data is sitting in my office, maybe we should try to do something with it...)

To answer your question, patients were randomly assigned as to which position they would be in initially. A reading was taken, and then the patient was (VERY CAREFULLY) repositioned to the second position while the measuring device was still in place.

 

[corpsmanUP]

Okay, this is going to sound nuts coming from someone so inexperienced. But I prefer the side as well because I learned from a neurologist who insisted on OP's and swore they were only accurate in the lateral recumbent position. I have found that I like the side route actually more than the sitting for positioning (and most important for repositioning when hitting bone multiple times in some old sclerotic person). What I have done the last few times to keep my midline orientation is I scoot the patient over as far as possible to the other side of the gurney or bed, have an MA or nurse support them (mostly for comfort), and then literally tilt my upper body to be parallel with theirs. I anchor my non-dominant hand forearm on the bed. Its almost like getting halfway in bed with them. I betadine from like their inion to their popliteal fossa (slight overexageration) because I do not like the drape at all. I think the stupid drape causes more landmark and angle distortion so I just don't use it. Our kids have the blue drapes, but I might deal better with them if they were transparent like our central line drapes. I'm definitely a side man now!!

 

[DrQuinn]

I've read, somewhere, that you can't measure the OP in a sitting patient, as the "column of water" is basically the entire spinal cord which is on top of your measurement spot. The only way to get an accurate reading is to to it with the patient in teh recumbent position where the pressure equalizes throughout the entire column, giving you an accurate reading.

*sigh* I stuck myself on an LP about 8 months ago with teh stylet needle. *sigh* Hep C positive. So, besides the whole lying flat thing, be careful holding that LP needle, and keep your fingers away from the end as you pull out your stylet (yes, I was a pGY3 when I did it).

Q

 

[colforbinMD]

Okay, this is going to sound nuts coming from someone so inexperienced. But I prefer the side as well because I learned from a neurologist who insisted on OP's and swore they were only accurate in the lateral recumbent position. I have found that I like the side route actually more than the sitting for positioning (and most important for repositioning when hitting bone multiple times in some old sclerotic person). What I have done the last few times to keep my midline orientation is I scoot the patient over as far as possible to the other side of the gurney or bed, have an MA or nurse support them (mostly for comfort), and then literally tilt my upper body to be parallel with theirs. I anchor my non-dominant hand forearm on the bed. Its almost like getting halfway in bed with them. I betadine from like their inion to their popliteal fossa (slight overexageration) because I do not like the drape at all. I think the stupid drape causes more landmark and angle distortion so I just don't use it. Our kids have the blue drapes, but I might deal better with them if they were transparent like our central line drapes. I'm definitely a side man now!!

Dying for a pic of the corpsman spoonstyle LP in action!!!
As for me I like to alternate every 3-5 or so LPs so I am proficient in both approaches and can then switch if having difficulties. I haven't kept track but would bet I am slightly more successful first attempt in the upright. Maybe I will try climing in bet with em to up my horizontal stats