Absolute contraindication to LP or LD

1. Signs of cerebral herniation or increased ICP 

Relative contraindication to LP or LD

1. Currently / recently received anticoagulation (spinal hematoma risk)

Checklist before procedure

• Consent the patient
  • remind that most common complication is post-tap HA. Other complications: cerebellar herniation, pain, HA, bleeding, infection, subarachnoid epidermal cyst, CSF leak 
• Type and screen within 72 hours
• Check Coags within 72 hours
• LDs can only happen in the ICU 
• LPs can happen anywhere (including floors) 
• Order extra 1% or 2% lidocaine with epi in case need to try another space
• Order CSF studies
• Order sedation
  • If not intubated: order 1x conscious sedation
    • TBA 
  • If intubated: order
    • TBA 

Supplies

Background Facts and Anatomy

• Lumbar Puncture – International Emergency Medicine Education Project (iem-student.org)
• NEJM LP video
• Most people's conus ends by L1, so L4-5 and L3-4 should be very safe. 

Universal Steps for Lumbar Punctures & Drains

Positioning

• Slide patient to side of bed and then roll into lateral decubitis (much rarer, upright) 
  • Right-handed people: LEFT lateral decubitis 
  • Left-handed people: RIGHT lateral decubitis 
• If you are doing this on an intubated patient and need more slack to turn patient to your preferred side, just ask the RT in the ICU to get some extension tubing, they can do that, your comfort is a priority because it will ultimately fall on the patient if you are not comfortable and fail
• use a skin marker to draw a line at level of umbilicus 

Note: upright position will not give you an accurate OP. 

Puncturing

• Enter at around 15 degrees, aim towards belly button

Note: venous plexus is in posterior epidural space

Pop occurs when you get through ligamentum flavum; advance in 2mm increments 

If source of blood is a SAH, then the blood will NOT clear

Troubleshooting poor flow

• Nerve root obstructing flow (rotate needle 90 degrees)
• Needle is clogged w/ blood (you will probably have to redo in new interspace)
• Flush / Aspirate extremely carefully; never more than 1-2 ccs 

Notes: 

• the purpose of having stylet in at all times is to not introduce a skin plug that will cause a subarachnoid epidermal cyst
• the bigger the needle, the bigger the CSF leak risk
• epidural blood patch is the cure for a leak

Measuring Opening Pressure

Tips for obtaining an accurate pressure:

• For intubated people, subtract ~5 because the PEEP artificially elevates CNS pressure
• Extend legs because belly pushing on spine artificially elevates CNS pressure 

Specific Steps

Troubleshooting

1. I'm definitely in, I felt the pop, I got a flash of serosangenous flow, but now it's stopped
   • raise HOB 
   • push on abdomen
2. x