Lumbar puncture

Disclaimer

These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline. 

Read the full PCH Emergency Department disclaimer.

Aim

To guide staff in performing lumbar puncture in children and to:
  1. Ensure the safety and comfort of the infant or child whilst obtaining a cerebrospinal fluid (CSF) sample.  
  2. Collect an adequate CSF sample to enable the diagnosis of central nervous system infections, inflammation and metabolic disorders without contaminating the specimen.

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.
  • A Lumbar puncture Health Facts 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).
  • CSF samples must be obtained with strict adherence to Aseptic Technique.
    • For comparison with CSF glucose a BGL should be obtained immediately before the procedure
  • An LP is only conducted after a thorough neurological examination and raised intracranial pressure (ICP) or other contraindications have been excluded.
  • A normal CT scan does not exclude raised ICP and is not a substitute for a thorough examination.
  • Difficult LP - where a non-urgent lumbar puncture is perceived to be difficult (e.g. patient body mass index > 30), consideration should be given at the outset as to whether the procedure would be better performed under image guidance. 
  • If a lumbar puncture is attempted unsuccessfully on two occasions, the patient should be referred to a more senior clinician to either perform the procedure or refer for it to be done under image guidance
  • For therapeutic lumbar puncture with intrathecal chemotherapy administration, refer to the Department of Oncology guidelines.

Indications

  • Suspected meningitis or encephalitis
  • Suspected sub-arachnoid haemorrhage with a normal CT
  • Measurement of opening pressure in suspected idiopathic intracranial hypertension
  • Therapeutic reduction in ICP in idiopathic intracranial hypertension
  • Disease staging and instillation of chemotherapy in oncology patients
  • To assist with the diagnosis of other central nervous system pathologies including demyelinating, neuroinflammatory and neurometabolic conditions.

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 unwell child).
  • Local infection at the needle insertion site.
  • Coagulation defects.
  • Cardiovascular compromise / shock.
  • Respiratory compromise e.g. baby with apnoeas.
  • Thrombocytopaenia.  If platelets < 50 discuss with Consultant

Preparation

Staff

  • Doctor performing the lumbar puncture.
  • One to two assistants will be required to assist with holding the patient and preparing the equipment – at least one should be a nurse / doctor experienced in clinical holding for a LP.

Equipment

  • Dressing trolley
  • Large dressing pack.
  • Sterile: gown, gloves, hand towel, fenestrated drape, gauze.
  • Appropriate skin antiseptic:
    • Infants, children, adolescents: 2% chlorhexidine & 70% isopropyl alcohol (e.g. Maxi swabstick) or 
    • povidone iodine if known sensitivity to chlorhexidine
    • Neonates ≥ 28 weeks gestation: 1% chlorhexidine & 70% isopropyl alcohol (swab stick preferable)
    • Preterm neonates < 28 weeks gestation: Povidone iodine solution
  • 3 sterile CSF specimen containers.
    • More than 3 containers may be required if multiple tests are required on the CSF sample. 
    • Minimum required volumes for each test are indicated in the PathWest test directory (http://pathlines.health.wa.gov.au/testdirectory/). Discuss with the Clinical Microbiologist prior to sample collection, if necessary.
  • Small transparent, semi permeable, occlusive dressing.
  • Spinal lumbar puncture needles (length depends on age).
  • 22G or 25G bevelled spinal needles with stylet. Needle length and gauge depend on the age and size of the child and the indication for lumbar puncture. Pencil point is preferred in older children to reduced risk of headache.

Lumbar puncture 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
  • Oral Conscious Sedation may be considered
  • 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

Prepare the trolley

  • Perform hand hygiene.
  • Decontaminate dressing trolley with a detergent wipe and allow it to dry prior to procedure set up.
  • Open sterile equipment onto sterile field.

Position of patient

  • Perform hand hygiene before touching the patient.
    Appropriate positioning increases the interspinous distance, facilitating access to meninges and CSF
    • Position the patient in a lateral position with the patient facing the holding nurse
    • Patient knees and chin are to be drawn to the chest, and body well flexed (foetal position)
    • The hips should be vertical to align the iliac crests i.e. back should be 90 degrees to the bed
    • The patients back should be positioned parallel and close to the edge of the bed with the hips vertically aligned.

Position of patient for lumbar puncture

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

  • Perform hand hygiene (Moment 1) before touching the patient.
  • 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 put on sterile gown and gloves.
  • Prepare skin with antiseptic swab sticks or sterile forceps and gauze:
    • Wipe antiseptic swab in a circular motion commencing at the proposed insertion site
    • Repeat with second swab stick or sterile forceps and gauze.
  • 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

Lumbar puncture needle insertion

  • Remove the stylet and check for CSF appearing at the needle hub:
  • If CSF is not flowing
    • Replace stylet and advance or reposition the needle slightly and recheck for CSF.
  • If CSF is flowing
    • If opening pressure required, connect manometer  to spinal needl
    • Collect 10 drops in each (x3) sterile container. (Note which container holds the first collection)
    • Minimum required volumes for each test are indicated in the PathWest test directory. Discuss with the Clinical Microbiologist prior to sample collection, if necessary.
  • 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
  • Remove personal protective equipment and perform hand hygiene (Moment 3).

Specimens

  • Label the CSF containers with the patient’s name, date of birth, UMRN and date and time of specimen collection.
  • Place labelled containers in a biohazard bag and send 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 microbiology scientist via switchboard to perform an urgent microscopy.

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.
  Neutrophils Lymphocytes Protein Glucose
Normal term neonate 0 < 20  < 1g/L > 2/3 serum glucose or
> 2.0mmol.L
Normal (> 1 month of age) 0 < 5 < 0.4g/L >2/3 serum glucose or
> 2.5mmol/L
Bacterial meningitis Very high Usually < 100  > 1g/L  Low
Viral meningitis Usually < 100 10-1000 Normal Normal

  • Partially treated bacterial meningitis may have a CSF picture of bacterial meningitis, viral meningitis 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:750 RBC in CSF is normal if a patient’s FBC is normal
    • A calculation may be used to correct the CSF WBC counts which are falsely increased due to a traumatic tap: 
      WBCs added = WBC(blood) x RBC(CSF) / RBC(blood)

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.

Bibliography

  1. Bonadio W. Pediatric Lumbar Puncture and Cerebrospinal Fluid Analysis. J Emerg Med 2014; 46: 141-150
  2. Arevalo-Rodriguez I, Ciapponi A, Roqué i Figuls M, Muñoz L & Bonfill Cosp X. Posture and fluids for preventing post-dural puncture headache. Cochrane  Database of Systematic Reviews 2016, Issue 3. Art. No.: CD009199. DOI: 10.1002/14651858.CD009199.pub3.
  3. Evans RW, Armon C, Frohman EM & Goodin DS. Assessment: prevention of post-lumbar puncture headaches. Report of the Therapeutics and Technology Assessment  Subcommittee of the American Academy of Neurology. Neurology 2000; 55(7): 909-14.
  4. E, Aerssens P, Alliet P, Gillis P & Raes M. Post-dural puncture headaches in children. A literature review. European Journal of Pediatrics 2003; 162: 117-21.

Endorsed by:  Director, Emergency Department   Date:  Nov 2017


 Review date:   Nov 2020


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