HTA Procedures

So you’ve been asked to teach someone how to do a procedure… or you’ve been asked to discuss it with a patient, or get consent…

Here’s How To Answer a Procedure question. There are defined steps to this answer, and they are:

 

  1. Indications
  2. Contraindications
  3. Complications
  4. Consent
  5. Preparation
  6. Performance
  7. Disposition & Follow up
  8. Documentation

 

Let’s go through these, with an example procedure; Lumbar Puncture.

Lumbar Puncture

Indications

  1. Diagnostic
    1. Analysis of CSF in meningitis, SAH, MS, GBS, Carcinomatosis
  2. Therapeutic
    1. Intrathecal administration of medications
    2. Removal of CSF in benign ICH

Contraindications

  1. Absolute
    1. Infection at intended puncture site
  2.  Relative
    1. Risk of cerebellar tonsillar herniation
      1. Known increased ICP from a space occupying lesion
      2. Reduced level of consciousness
      3. Focal neurological deficits eg unilateral CN III palsy
      4. seizures
    2. Risk of Bleeding
      1. Uncontrolled bleeding diathesis
      2. Thrombocytopaenia <40
      3. Heparin >10,000 u per day
    3. Prior spinal surgery at the intended level

Complications

  1. Post-dural-puncture headache
  2. Infection
    1. epidural abscess
    2. meningitis
  3. Bleeding
    1. subarachnoid haemorrhage
    2. epidural haematoma
    3. subdural haematoma
  4. Neuropraxia
    1. cauda equina (infection / bleeding)
    2. back/leg pain
  5. Cranial Nerve VI Palsy
  6. epidermoid tumour

Consent

Preparation

  1. Patient
    1. consented and positioned
    2. lateral decubitus or upright
  2. Area
    1. equipped with oxygen and a monitor
  3. Equipment
    1. LP kit
    2. sprotte/whittaker needle 22-28G
    3. sterile prep/drape/gown/glove/mask/hat
  4. Drugs
    1. midazolam 0.1-0.3mg/kg
    2. fentanyl 0.5-1.5mcg/kg

Performance

  1. procedural sedation with midazolam 0.1-0.2mg/kg and fentanyl 0.5-1mcg/kg if needed.
  2. palpate iliac crests – a line connecting these should traverse L4
    up to 30% adults have spinal cord to body of L2, therefore approach is L2/3 downward, ideally L3/4
  3. maximal lumbar kyphosis to open interspaces
  4. lignocaine & adrenaline to skin, soft tissue and ligaments
  5. midline or oblique approach
  6. ligaments traversed are supraspinous, interspinous, flavum
  7. usually 2/3 depth of LP needle, aside from obese.
  8. measure pressure if in lateral decubitus (normal <20-25)
  9. collect 5-10mL fluid in 3-4 containers
  10. reinsert trochar to withdraw
  11. simple dressing

Disposition & Follow up

  1. no requirement to lay supine for any period of time
  2. PDPH 2-6% of cases with small sprotte needles, advise pt about headache etc and encourage them to return
  3. if clinically indicated steroids then antibiotics may be appropriate
  4. keep until results back (xanthochromia / MC&S)

Documentation