Lumbar Punctures Flashcards
What is an LP
Indications for an LP
Lumbar Puncture (LP) : a diagnostic clinical procedure in which a thin, hollow needle is inserted inot the subarachnoid space of the spinal cord to extract CSF for examination
Indications :
Infectious Etiolgoies: meningitis, encephalitis, myleitis
Inflammatory: MS, GBS, vasculitis
Malignancy: primary or paraneoplastic syndromes
Subarrachnoid Hemorrhages
Normal Pressure Hydrocephalus
Indications: Therapeudic
- releaving idopathic intracranial hypertension (psuedotumor cerebri)
- cryptococcus meningitis
- normal pressure hydrocephalus (increase CSF within the ventricles)
Administeration of
- abx.
- intrathecal chemo
- contrats dye
Absolute Contraindications of an LP
Relative LP Contraindications
Absloute Contraindications
- increase ICP with signs of impending hernation
- suspecte CNS mass lesion
- local skin infection over area of LP
those with uncorrected bleeding disorders
- using anitcoags)
- those with uncontrolled coagulopathy (INR > 1.4)
- dysfunctional platlemts
- platelets < 50,000
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Relative Contraindications
- uncooperative pt.
- severe degenerative joint disease
- histoyr of neurosurgery with hardware placement
Considerations before performing an LP on a pt.
other symptoms which may prompt you to wait for further imaging before doing an LP
symptoms pointing toward possible increased ICP
Obtain head imaing (CT/MRI) if concerned about active bleeding or intracranial processes
signs…
- unexplained acute AMS
- focal neuro deficts
Increased ICP
- acute change in LOC : lethargy, confusion, agitiaion, restlessness/irritability, seizures
- acute changes or loss of motor/sensory fuction: atoaxia, aphasia
- pupillary changes
LP Procedure: Informed Consent
- whats included
- waht risks/complicatinos to warn pt.
Infored Consent
- disccus benefits/risks & indications/contraindications
- potential complications
- give sumary of procedure
- peri-procedure guidance
Risks & Complications of an LP to include
- bleeding (epidura hematoma)
- infection
- injury to surrouding anatomical structures: brain hemorrhage, injury to SC, injury to aorta/vena cava, siatic nerve pain
Headache: due to change in pressure & stretch of meningies
- improved with lying down, hydration and caffeine
- if > 1-2 days : concern for CSF leaf & need blood patch at LP site
Back Pain: resolvable; over site of tap
LP Procecure: Equiptment
Anti-Septic Equiptment
- drapes, gloves, beatdine/chorahex.
Analgesics
lidocaine
Collection
- tubes and needles and manometer
- Spinal Catheter: 20 or 22 gauge
- 3.5 inches
- 6 inches for larger pt.
LP Procedure: Steps
gather equiptement & wash hands
Postition Patient
- can be in the lateral recumbent/fetal postion
- can be sitting up, bending over
Mark patients site of procedure
- palapet for superior aspect of illiac crest to find L4
- palpate C7 to find midline
- mark intervertebral space L3/L3 or L4/L5
Proceudre/Safety Time out
- ensure name DOB and allergies and labs
Clean Site
- anaseptic agents (cholrhexadine or iodine
Don Sterile
- gloves, cap and mask and eyes
Set Up kit
- draw up lidocaine
- set up your tubes
- extension tube handy
- manometer if obtainiedn opening pressure
Drape site
LP Steps: after draping site
anesthetic details and spinal needle details
Anestheize the area
- repalpate landmarks
- create a wheal of lidocaine under the skin to numbe superfiscial
- then using longer anesthetizing needle: insert directly toward the belly button (the tragetory of the spinal needle)
- advance this needle with slight pull to aspirate then inject lidocine
- deposit .5cc lidocaine intermittently until needle fully in & then deposit rest on your way out
Insert Spinal Needle
- conventional needle or atramatic needle
- bevel should be facing the side of the pt. (either left or right of the spine)
- insert needle with angle towards umbillicus
- initally advance 3cm before removing stylet to see if there is fluid
detaisl on how to reposition the needle during an LP
- when checking for CSF fluid: replace the stylet and withidraw the needle to the subcutanenous level of tissue
- repalpate the landmarks and redirect the needle
- decide if you’re hitting bone early or late
- can consider using US
how is the opening pressure measured during an LP
once CSF flow is established…
- remove stylet and attach the manometer to the end of the needle
- have pt. slowly straighten legs if able to
- the fluid will climb the manometer
once level of fliud in the manometer levels off, read the height
normal opening pressure is 10-20 cm H2O
measure closing pressure if indicated as well
ALWAYS OBTAIN OPENING PRESSURE BEFORE GETTING CSF SAMPLES
Obtaining the Samples of CSF: Specifics on tubes and how to collect
Obtaining the CSF samples
- obtain opening pressure first
- use extension tubing
- fill tubes
Tube #1 = cell count #1
Tube #2 = Chemistires & serologic testing
Tube #3 = Micro tests
Tube #4 = Cell Counts #2
Noraml CSF = clear
Xanthochormoic = yellow
- could indicated “old” blood
- bilirubin, carotene, protein or melanoma in the CSF
Post Procedure: LP
what do you do
after samples are obtained….
- reinsert the styloid ito catheter and withdrawl the needle
- immediately apple pressur with adheasive bandage
Histortically = told ot lay flat however no evidence on this helping with a post-LP headache
label and sent specimens to lab
starta abx. empiritcally if needed
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