Paediatric Acute care Guidelines PMH Emergency Department

Pre-Procedure

  • Patients who require a lumbar puncture (LP) must be discussed with an ED Consultant or Senior Doctor before commencing the procedure
  • A lumbar puncture should never delay potentially life saving interventions such as the administration of antibiotics to patients with suspected bacterial meningitis
  • Informed verbal consent is required prior to commencement of an LP. This should include discussion and explanations about the diagnostic benefits of the procedure and the potential complications.
  • The Lumbar Puncture Health Fact Sheet should be provided to parents to assist with consent and education

General

  • Lumbar puncture is the procedure used to obtain cerebral spinal fluid (CSF)
  • It is conducted after a thorough neurological examination and raised intracranial pressure (ICP) has been excluded
  • A normal CT scan does not exclude raised ICP and is not a substitute for a thorough examination

Indications

  • Suspected meningitis or encephalitis
  • Suspected sub-arachnoid haemorrhage with a normal CT
  • Measurement of opening pressure in suspected benign intracranial hypertension
  • Therapeutic reduction in ICP in benign intracranial hypertension
  • Disease staging and instillation of chemotherapy in oncology patients

 

Contraindications

  • Coma or decreased conscious state: absent/non-purposeful response to painful stimuli
  • Signs of raised intracranial pressure (ICP):
    • Altered pupillary responses
    • Absent Doll’s eye reflexes
    • Decerebrate or decorticate posturing
    • Papilloedema
    • Abnormal respiratory pattern, hypertension, bradycardia (Cushing’s Triad)
  • Within 30 minutes of seizure or if normal conscious level has not returned post seizure
  • New focal neurological signs – hemiparesis, extensor plantar responses, ocular palsies
  • Strong suspicion of meningococcal infection with risk of Disseminated Intravascular Coagulation (typical purpuric rash in an ill child)
  • Local infection at the needle insertion site
  • Coagulation defects
  • Thrombocytopaenia
  • Cardiovascular compromise/ shock
  • Respiratory compromise – e.g. baby with apnoeas

 

Preparation

Staff

  • Doctor performing the lumbar puncture
  • One to two assistants will be required to hold the patient and prepare the equipment – at least one should be experienced in clinical holding for the LP

Equipment

  • Large dressing pack
  • Sterile: gown, gloves, hand towel, fenestrated drape, gauze
  • 2 maxi swab sticks (impregnated with 2% chlorhexidine and 70% alcohol)
  • 2 sterile CSF specimen containers
  • Small transparent, semi permeable, occlusive dressing
  • Spinal lumbar puncture needles (length depends on age)
  • 22G or 25G bevelled spinal needles with stylet

LP equipment

Additional equipment that may be required:

  • Local anaesthetic, 2ml / 5ml syringe, needles
  • Surgical face mask
  • Protective eye goggles
  • Manometer set

 

Procedural Sedation and Analgesia
  • Apply topical anaesthetic cream (e.g. EMLA) to insertion site and cover with occlusive dressing for 45-60 minutes (except where specimens are urgent)
During the procedure options are:

  • Local anaesthetic (1% lignocaine) infiltration
  • Oral sucrose for infants < 3 months old
  • Nitrous oxide for children older than 3 years with a normal conscious state
  • Non-pharmacological techniques
  • Distraction, parental presence

 

Monitoring

  • All seriously ill children require continuous pulse oximetry monitoring
  • Consider cardiac monitoring where appropriate
  • When sedation has been used follow the relevant protocol/ guideline
  • A minimum of hourly neurological observations are required for all patients post procedure

Procedure

Positioning and technique

Position of Patient

  • Appropriate positioning increases the interspinous distance, facilitating access to meninges and CSF
    • Position the patient in a lateral position, patient facing the holding nurse
    • Patient knees and chin are to be drawn to the chest, and body well flexed (fetal position)
    • The hips should be vertical to align the iliac crests i.e. back should be 90 degrees to the bed.
    • The patient’s back should be close to the edge of the bed to allow easy access


LP-Position

 

 

 

 

 

  

Alternatively:

  • Older patients may prefer to remain in a sitting position. Have the patient slouch shoulders over a pillow without bending at the hips and maintaining the 90 degree back to bed position.
  • Avoid over flexion of the neck, especially in infants as respiratory compromise may result

Preparation

  • Identify the LP site – a line between the top of the iliac crest intersects the spine at approximately the L3/L4 interspace:
    • Site for needle insertion should be L3/L4 or L4/L5 interspace
  • Wash hands using aseptic technique and don sterile gown and gloves
  • Prepare skin with antiseptic swab sticks:
    • Wipe antiseptic swab in a circular motion commencing at the proposed insertion site
    • Repeat with second swab stick
  • Drape the patient with the fenestrated sterile drape ensuring the airway is visible at all times
  • Remove caps from the CSF specimen containers
  • Identify the landmarks and palpate the needle insertion point
  • If using local anaesthetic:
    • Infiltrate the skin with 1% lignocaine (allow 1-2 minutes for anaesthetic effects)
  • Ensure the skin is dry prior to the needle insertion
  • Reconfirm the land marks and LP site prior to the needle insertion

Spinal Needle Insertion

  • Hold the spinal needle so that bevel is in the superior position (facing up)
  • With the stylet in position, insert the needle through the skin and wait for any patient movement to stop
  • Aiming for the umbilicus, advance the needle in the spinous ligament until there is a decrease in resistance

LP-Needle-Insertion

 

 

 

 

 

 

 

  • Remove the stylet and check for CSF appearing at the needle hub:
    • If CSF is not flowing:
      • Replace stylet and advance the needle slightly and recheck for CSF
    • If CSF is flowing:
      • Collect 10 drops in each (2) sterile containers. (Note which container holds the first collection)
  • When sample collection is complete, reinsert the stylet
  • Remove the needle and stylet
  • Use sterile gauze to apply gentle pressure to the insertion site
  • Cover the insertion site with a transparent occlusive dressing (e.g. Tegaderm), which should remain in situ for 24 hours

Specimens

  • Should be sent urgently to the laboratory for cell count, protein, glucose, microscopy and culture. CSF PCR (Herpes Simplex, Enterovirus etc should be requested as indicated).
  • If specimen collection occurs outside of laboratory opening hours, contact the on-call Microbiologist via the switchboard.

 

Post-Procedure

Complications

  • Failure to obtain specimen, repeated attempts (common)
  • Headaches (common, up to 15%)
  • Backaches
  • Transient/ persistent paraesthesiae/ numbness
  • Cerebral herniation
  • Intracranial subdural haemorrhage
  • Spinal epidural haemorrhage
  • Paraplegia
  • Infection
  • Cardiorespiratory compromise due to positioning
  • Spinal epidermoid tumours associated with needles without a stylet (rare)

Aftercare

  • A minimum of hourly neurological observations are required for all patients post procedure, including checking of LP site

CSF Interpretation

  • All CSF should be sent for urgent cell count, protein, glucose, microscopy and culture.
  • Normal CSF should not contain neutrophils but may have variable WBC depending on age.
  • The table below can be used as a guide for CSF interpretation:
  Neutrophils Lymphocytes  Protein  Glucose 
Normal Term Neonate  0  <20 <1.0g/L 

 >2/3 Serum glucose
or
>2.0mmol/L

Normal
(>1 month
 age)
 0  <5  <0.4g/L  >2/3 Serum glucose
or
>2.5mmol/L
Bacterial Meningitis   Very High Usually <100  >1.0g/L low 
Viral Meningitis  Usually <100 10-1000  Normal Normal 
  • Partially treated bacterial meningitis may have a CSF picture of bacterial meningitis, viral meninigitis or a combination of both.
  • Blood stained CSF from a traumatic procedure can be more difficult to interpret. 
  • There are various methods to calculate whether WCC is significant in a traumatic tap:
    • A ratio of 1 WBC to 750 RBC in CSF is normal if a patient’s FBC is normal
    • A calculation may be used to correct CSF WBC counts which are falsely increased due to a traumatic tap: 
      • WBCs added = WBC(blood) x RBC(CSF) / RBC(blood)

More

Evidence points

  • Current available evidence does not support bed rest over immediate mobilisation in the reduction of postural headaches; therefore routine bed rest is not required.

References

PMH ED Guideline: Lumbar Puncture – Last Updated: July 2014
Bonadio W. Pediatric Lumbar Puncture and Cerebrospinal Fluid Analysis. J Emerg Med 2014; 46: 141-150

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