Lumbar Puncture Flashcards
Name seven indications to obtain a CSF sample?
- Meningitis
- Meningoencephalitis
- Subarachnoid hemorrhage
- Malignancy – diagnosis and treatment
- Idiopathic Intracranial Hypertension
- Other neurologic syndromes
- Infusion of Drugs or contrast
Name four contraindications for LP
- Unstable patient with cardiovascular or respiratory instability
- Localised skin/soft tissue infection over puncture site
- Evidence of unstable bleeding disorder < 50 000 platelets
- Increased ICP
Name the equipment required
- Anaesthetics - topical (EMLA, elamax) and lidocaine
- Povidone
- Drapes, gauze and bandages
- Manometer, stopcock and tubing in non-infant kits
- Spinal needle (22 gauge) or atraumatic needles (less spina headaches)
Name the required position for LP
Lateral decubitus position
Describe the lateral decubitus position
- Maximally flex spine without compromising airway
- Keep alignment of feet, knees and hips
- Position head to left if right handed or vice versa
Name the steps in the procedure to insert the spinal needle
- Cleanse skin with povidone iodine from puncture site radially out to 10 cm and ALLOW TO DRY
- Insert spinal needle with stylet with bevel. Aim towards umbilicus
- A ‘pop’ of sudden decrease in resistance indicated that ligament flavour and dura are punctured
- Remove stylet and check for flow of spinal fluid
What to do if there is no fluid when stylet is removed?
- Rotate needle 90 degrees
* Reinsert stylet and advance needle slowly chuckling frequently for CSF
What is the effect of jugular vein compression on CSF?
Increases pressure in low flow situations
Why to do if there is bony resistance?
- If immediate, then not in spinal interspace
* If deep, withdraw needle to the skin surface and redirect more cephalad and increase patient flexion
What is used to measure the pressure of CSF flow?
Manometry
How do you use a manometer?
- Pressure can only be accurately measured in lateral decubitus position and in the relaxed patient
- Attach with a 3-way stopcock when free flow of CSF is obtained
- Read column when highest level is achieved and respiratory variation is noted
Describe steps in retrieval of CSF and removal of spinal needle
- Collect three 1ml vials of CSF
- Check closuring pressure with manometer
- Resinsert stylet and remove needle
- Cleanse back and cover puncture site
Why are three 1ml vials collected?
- 1 - culture and gram stain
- 2 - glucose, protein
- 3 - cell count and differential and extra CSF is desired for other lab tests
Why is the sitting position used?
Sitting position in children:
• Hold infant’s hands between flexed legs with one hand and flex head with the other hand
• Insert needle so bevel is parallel to spinal cord
(Cannot measure pressure accurately in this position)
Why is the paramedic (lateral) approach?
- Use for patients who have calcifications from repeated LPs or anatomic abnormalities
- Needle passes through erector spinae muscles, and ligamentum flavum - bypasses supraspinal and interspinal ligaments
- Less incidence of spinal headache
