intro clin skills lp
TRANSCRIPT
Clinical Skills:Clinical Skills:
Lumbar PunctureLumbar Puncture
ConsiderationsConsiderations
• Why is an LP Being Done?• Is this the Only Test Available?• What Positive Information is
Expected?• Is the Patient Stable?
IndicationsIndications• Diagnostic
• Infection• Subarachnoid Hemorrhage• Multiple Sclerosis
• Therapeutic• Neoplasm• Benign intracranial hypertension (BIH)
• Incidental• Myelography : is a type of radiographic
examination that uses a contrast medium to detect pathology of the spinal cord
ContraindicationsContraindications• Suspected Increase in ICP
• Exception: therapeutic use of lumbar puncture to reduce ICP • Suspected Spinal Cord Compression• Infection at the Site of an LP• Coagulopathy.
Abnormal respiratory pattern Hypertension with bradycardia and deteriorating
consciousness Vertebral deformities , in hands of an inexperienced
physician.
Normal CSF ValuesNormal CSF Values• Appears to be clear and colorless• Opening Pressure ~ 120 mm/H20• Protein level ~ 35 mg%• Glucose level ~ 60 mg %• (60% of serum glucose)
• Cells < 5 lymphocytic/monocytic
CSF Profile’sCSF Profile’s
Pressure Cells Protein Glucose
Bacterial Meningitis
(PMN’s)
to
Viral Meningitis
N to
to (Mono’s)
N
TECHNIQUE
Preparation — An LP can be performed with the patient in the lateral recumbent position or sitting upright.
The lateral recumbent position is preferred because it allows accurate measurement of the opening pressure
Equipment Most CSF trays come with:
– Anesthetic such as: Topical - Zylocaine cream Lidocaine 1% with 25 gauge needle and
syringe– Povidone-iodine solution & sponge
wand– Drapes, gauze, and bandages– Manometer, stopcock and tubing in
non-infant kits
Equipment Spinal needle, usually 22 gauge
– 1.5 in for < 1 yr– 2.5 in for 1 year to middle
childhood– 3.5 in for older children and
adolescents– Larger for large adolescents
Atraumatic needles, less spinal headaches
Lateral Decubitus Position
Apply topical anesthetic 30-45 min prior to procedure Spinal cord ends at L1-L2, so sites for puncture are located at L3-L4
or L4-L5 Restrain patient in 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
Preparation for the LPPreparation for the LP (one)(one)
Preparation for the LPPreparation for the LP (two)(two)
Aseptic technique
The overlying skin should be cleaned with alcohol and a disinfectant such as povidone-iodine or chlorhexidine (0.5 percent in alcohol 70 percent);
the antiseptic should be allowed to dry before the procedure is begun.
Procedure
Insert spinal needle with stylet with bevel up to keep cutting edge parallel with nerve and ligament fibers
Procedure
Aim towards umbilicus directing needle slightly cephalad
Hold needle firmly
Procedure
A “pop” of sudden decrease in resistance indicates that ligamentum flavum and dura are punctured
Remove stylet and check for flow of spinal fluid
Procedure If no fluid, then:
– Rotate needle 90°– Reinsert stylet and advance needle slowly checking frequently for
CSF Jugular vein compression can increase CSF pressure in low flow
situations If bony resistance is felt immediately then you are not in the spinal
interspace If bony resistance is felt deeply, then withdraw needle to the skin
surface and redirect more cephalad and increase patient flexion If bloody fluid that does not clear or that clots results, then withdraw
needle and reattempt at a different interspace
Manometry
When CSF flows, attach manometer to obtain opening pressure if desired
Pressure can only be accurately measured in lateral decubitus position and in the relaxed patient
Attach manometer with a 3-way stopcock when free flow of CSF is obtained
Read column when highest level is achieved and respiratory variation is noted
Complications Headache
– Uncommon in < 10 y/o Apnea (central or obstructive) Back pain
– Occasionally with short-lived referred limp– Disc herniation if needle advanced too far
Bleeding or fluid leak around spinal cord Infection, pain, hematoma Subarachnoid epidermal cyst Ocular muscle palsy (transient) Nerve Trauma Brainstem herniation
Procedure
Collect 1ml of CSF in each of 3 vials for:– Tube 1: culture & gram stain– Tube 2: glucose, protein– Tube 3: cell count & differential– and extra CSF if desired for other lab tests
Check closing pressure with manometer, if desired Reinsert stylet and remove needle in one quick motion Cleanse back and cover puncture site
Sitting Position Restrain infant in the seated position
with maximal spinal flexion– Hold infant’s hands between flexed
legs with one hand and flex head with the other hand
Drape patient below buttocks and fenestrated drape opening over puncture site
Insert needle so bevel is parallel to spinal cord (Bevel left or right)
Cannot measure pressure accurately in this position
Paramedian (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
Spinal Headache Most common complication Risk factors: female, age 18-30, lower BMI, hx of
HA, prior spinal HA Can last hours to weeks
Treatment:– Supine position for at least 2 hours – Hydration– Caffeine either PO or IV– Epidural blood patch
Spinal Headache Prevention
Can avoid by:– Passing needle bevel parallel to longitudinal
fibers of dura– Replacing stylet before removing needle– Using small diameter needles– Using atraumatic needles
Bed rest or PO intake after LP does not reduce incidence of headache
Nerve Root Trauma/Irritation
Can feel electric shocks or dysesthesias Back pain can persist for months
– Consider disc herniation Rarely permanent Withdraw needle immediately If pain or motor weakness persists, start corticosteroids Electromyogram/nerve conduction velocity studies should
be scheduled if pain persists
Herniation
Manifests initially as altered mental status, followed by cranial nerve abnormalities and Cushing triad
May be rapidly fatal. Immediately remove needle and raise the head of bed to
30-45° improve venous return from the brain. Mannitol or 3% Saline Intubate patient and hyperventilate Emergent neurosurgical consult
Thanks for attention