Lumbar punctures (LPs) can be tricky even for an experienced provider. Here are some pro tips to help you look like an all-star!

Set up:

  • The LP tray contains only a small amount of  lidocaine (~3mls). If you need to make a second attempt in another intervertebral space you may not have enough remaining anesthetic. Bring an additional vial of lidocaine with you so you don’t have to leave the bedside mid procedure.
  • Using tape, secure the additional vial of lidocaine upside down to an IV pole. This way you can refill your syringe without breaking sterility.
  • Using too much lidocaine will distort your anatomy. Inject 1cc under the skin like a TB test – this is often enough.

Patient Positing:

  • When doing an upright LP have the patient rest their feet on a stool or the seat of a chair, this helps accentuate hip flexion and opens the intervertebral spaces.

Procedure: 

  • Although the traditional teaching is to use the L4/L5  intervertebral space, the L3/L4 intervertebral space is actually wider and easier to penetrate – I always jump up one space.
  • The legendary “two pops” is subtle and often unappreciated by most providers.  Forget about this silly rule all together. Just know that in most patients (with normal BMIs) you will have to insert the needle 50-75% of the total length before obtaining CSF. In the obese, you may need to hub your needle before obtaining CSF.
  • If the patient complains of sciatic-like pain during the procedure this is extremely helpful information – it means your needle is too far lateral and you are hitting either the right or left spinal nerve. Ask the patient which leg they have pain in and reposition your needle accordingly.
  • If you get gross blood… Congratulations! You have hit the spinal venous plexus! Go ahead and place your US-guided IV! Just kidding… the spinal venous plexus surrounds the dura which means you are very close to the correct spot – just a little too shallow. Simply, insert the needle 2-mm at a time and withdraw the stylet to check for CSF.
  • If your needle is bending, try again with a thicker gauge. I like an 18 gauge – it’s more rigid and less likely to bend. These are, however, not found in the LP tray; but can be found in either Resus or Cardiac.

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References:

http://www.oxodocs.com/oxo_articles/425/How-to-do-a-Lumbar-Puncture:-Instructions-from-a-practising-neurologist.html

Lumbar Puncture Part 2: Pearls, Pitfalls, and Troubleshooting