LP Flashcards
When to perform
Meningitis Meningoencephalitis SAH Malignancy Idiopathic intracranial hypertension Infusion of drugs
Contraindications
Patient with Cardiovascular/respiratory failure
Localised infection of skin over site
Evidence of bleeding disorder
Increased ICP: always do CT before LP but do not delay administration of antibiotics if meningitis is suspected
Things to pay attention to
- Must be below the end of the spinal cord
- Be aware of Chiari malformations: deformation where part of the brainstem pushed down into the spinal canal
Equipment used
Anaestetic : topical/lidocaine
Povidone-iodine solution with sponge
Drapes, gauze and bandages
Manometer (used to measure pressure), stopcock (controls opening and closing of system) and tubing in Non-infants
Spinal needle
-Usually a 22 gauge
-Atraumatic needles used to reduce chances of spinal headaches
Different positions
Lateral decubitus
sitting
Paramedial/lateral
Sitting position
Seated position with maximum flexion
Hold infants hands between flexed legs with one hand and flex head with other
Insert needle so that bevel is parallel with spinal cord
Will not be accurate pressure
Paramedian postion
- Use for patients who have calcifications for repeated LPs
- Use for patients with anatomical abnormalities
- Needle passes through erector spinae muscles and ligamentum flavum
Lateral decubitus position
- Maximally stretched spine without compromising the airway
- Keep alignment of feet, knees and hips
- Head on left if rig and viceversa
Procedure
-Clean skin with povidone-iodine solution - 10cm radius, allow to dry
-Drape around site
-Anaestetise with lidocaine if topical has not been used:
Intradermally using a Wheal at insertion
Insert needle through wheal being careful to not hit the blood vessels
-Insertion of needle
Insert needle with stylet with bevel pointing upwards: Keeps cutting edge parallel with nerves and fibres
Aim needle towards umbilicus slightly cephalic
Pop in pressure indicates that the ligaments flavum and the dura have been punctured
Remove stylet and see if spinal fluid
-Attach manometer and get initial reading
-Attach stopcock when CSF flow is achieved
-Collect 1ml of spinal fluid for 3 vials:
Culture and gram stain
Glucose, protein
Cell count and differential
- Check closing pressure
- Reinsert stylet and remove needle
- Clease back and cover site
What do to if no CSF come out
- Rotate needle by 90 degrees
- Reinsert stylet and reinsert needle slowly checking for CSF
- JV compression can increase CSF flow
- If bony resistance is felt straight way you are not in the spinal interspace
- If bony resistance is felt deeply then remove needle and re-insert needle more cephalad and increase patient flexion
- If bloody material that does not clear- remove needle and try different interspace
Complications
- Apnea
- Back pain (could be caused by slipped disc if not performed properly)
- Bleeding
- Infection
- Nerve trauma:
- Brainstem herniation :
- Epidermal inclusion cyst
- Ocular muscle palsy
- Headache
Nerve trauma
Needle needs to be removed immediately
Dysaestesia feeling
If pain persists: corticosteroids
If pain persists: nerve conduction studies
brainstem herniation
Altered mental state- cranial nerve dysfunction Remove needle immediately Mannitol Intubate patient Neuro consult
Epidermal inclusion cyst
Due to core of skin is pushed into spinal space
Do not remove stylet until through skin
spinal headaches
Most common complication
Can last hours to weeks
Bilateral
Treatment:Supine position for at least 2 hours, hydration, caffeine, epidural patch
Risk factors: female, low BMI, history of headaches
Prevention: reinserting stylet before removing needle, small diameter needles, atrumatic needles , bevel parallel to longitudinal fibres
