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:
- Indications
- Contraindications
- Complications
- Consent
- Preparation
- Performance
- Disposition & Follow up
- Documentation
Let’s go through these, with an example procedure; Lumbar Puncture.
Lumbar Puncture
Indications
- Diagnostic
- Analysis of CSF in meningitis, SAH, MS, GBS, Carcinomatosis
- Therapeutic
- Intrathecal administration of medications
- Removal of CSF in benign ICH
Contraindications
- Absolute
- Infection at intended puncture site
- Relative
- Risk of cerebellar tonsillar herniation
- Known increased ICP from a space occupying lesion
- Reduced level of consciousness
- Focal neurological deficits eg unilateral CN III palsy
- seizures
- Risk of Bleeding
- Uncontrolled bleeding diathesis
- Thrombocytopaenia <40
- Heparin >10,000 u per day
- Prior spinal surgery at the intended level
- Risk of cerebellar tonsillar herniation
Complications
- Post-dural-puncture headache
- Infection
- epidural abscess
- meningitis
- Bleeding
- subarachnoid haemorrhage
- epidural haematoma
- subdural haematoma
- Neuropraxia
- cauda equina (infection / bleeding)
- back/leg pain
- Cranial Nerve VI Palsy
- epidermoid tumour
Consent
Preparation
- Patient
- consented and positioned
- lateral decubitus or upright
- Area
- equipped with oxygen and a monitor
- Equipment
- LP kit
- sprotte/whittaker needle 22-28G
- sterile prep/drape/gown/glove/mask/hat
- Drugs
- midazolam 0.1-0.3mg/kg
- fentanyl 0.5-1.5mcg/kg
Performance
- procedural sedation with midazolam 0.1-0.2mg/kg and fentanyl 0.5-1mcg/kg if needed.
- 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 - maximal lumbar kyphosis to open interspaces
- lignocaine & adrenaline to skin, soft tissue and ligaments
- midline or oblique approach
- ligaments traversed are supraspinous, interspinous, flavum
- usually 2/3 depth of LP needle, aside from obese.
- measure pressure if in lateral decubitus (normal <20-25)
- collect 5-10mL fluid in 3-4 containers
- reinsert trochar to withdraw
- simple dressing
Disposition & Follow up
- no requirement to lay supine for any period of time
- PDPH 2-6% of cases with small sprotte needles, advise pt about headache etc and encourage them to return
- if clinically indicated steroids then antibiotics may be appropriate
- keep until results back (xanthochromia / MC&S)
Documentation