Brain Death Hot Case

GENERAL APPROACH

Brain death definition

• Brain death is the irreversible loss of all functions of the brain, including the brainstem
• The three essential findings in brain death are coma (unresponsiveness), absence of brainstem reflexes, and apnoea

Approach

• underlying diagnosis (e.g. SAH, TBI, severe hypoxic brain injury)
• duration of current neurological state
• exclude reversible causes
• perform brain death examination
• neuroimaging

INTRODUCTION

CUBICLE

INFUSIONS

• no sedation
• last dose of NMB?
• nimodipine (likely SAH)

VENTILATOR

• no spontaneous breaths

MONITOR

• raised ICP
• bradycardia and hypertension (Cushing’s response)
• exclude hypothermia

EQUIPMENT

• ICP monitor and duration (calibration drift after 5 days)
• EVD with blood-stained CSF
• cooling blanket or cooling machine (suggests post-cardiac arrest; could also be TBI with ICP management)
• high urine output (DI)

QUESTION SPECIFIC EXAMINATION

• note requirements (4h observation, then independent examination by 2 experienced clinicians)
• check preconditions
• request equipment
  • torch
  • cotton bud
  • tongue depressor
  • otoscope
  • ice cold water and 20mL syringe
  • peripheral nerve stimulator
  • Mapleson C ciruit (apnea testing, allow PEEP and observe for respiratory effort) or oxygen catheter
  • laryngoscope (test gag with direct vision)
• perform ‘train of four’ at 40 mV (likely will be told result)
• perform GCS
• test pain response
  • supra-orbital ridges (CN5), TMJ (CN5), sternal rub (trunk) and a nail bed on each limb
  • look for grimace (CN7)
  • note that spinal reflexes do not preclude brain death
• test pupil response to light (CN2 and CN3)
• test corneal reflex (CN5 and CN7)
• test vestibulo-ocular reflex: (CN3,6,8): check ear canals, assistant holds eyelids open, 20 mL cold water into each ear canal with towel and kidney dish, observe for 60 seconds (oculo-cephalic reflex not part of Australian brain death testing)
• test gag with laryngoscope and cough with suction catheter (CN9, 10)
• test for spontaneous ventilation — FiO2 1.0 then passive oxygenation with Mapleson C circuit or O2 catheter in ETT with 2L/min; allow CO2 to rise to 60 mmHg with pH <7.3 (or 20 mmHg above baseline if COPD); expect rise of 3 mmHg/min in PCO2 unless high O2 flow

RELEVANT INVESTIGATIONS

• 24 hour urine output (DI)
• UEC, ABG (normal electrolyte and metabolic state?)
• recent CT Head
• other neuro-imaging e.g. 4 vessel cerebral angiogram

Questions

• temperature?
• irreversible cause for coma?
• duration of neurological state?
• last dose of sedation or NMB?
• possibility of toxic cause?
• normal metabolic and endocrine status?

OPENING STATEMENT

• “This person is brain because…” or
• “This person does not meet the preconditions for brain death testing…” or
• ” this person is not brain dead…

DISCUSSION

• DDX of fixed dilated pupils
• requirements for certification of brain death
• diagnosis of brain death in presence of cervical spine or severe facial injuries
• when to order a 4-vessel angiogram and role of radio-isotope imaging
• difference between brain death and similar states (e.g. locked-in syndrome, persistent vegetative state)
• how to discuss organ donation with the family
• management problems of the organ donor prior to donation

References And Links

• CCC — Brain Death
• CCC — Changes in Brain Death Consensus Statement
• CCC — Observations Compatible and Incompatible with Brain Death
• CCC — Coma-like syndromes
• CCC — Management of the organ donation patient