Diagnosis and confirmation of death


Based on guidance from The Medical Academy of Royal Colleges
For full details read the full document.

Following cardiorespiratory arrest:

Observe the patient for 5 minutes.

Confirm:

  • Absence of pulse on palpation
  • Absence of heart sounds on auscultation
Can supplement above with:
  • Asystole on a continuous ECG display.
  • Absence of pulsatile flow using direct intra-arterial pressure monitoring.
  • Absence of contractile activity using echocardiography.
Any spontaneous return of cardiac or respiratory activity during this period of observation should prompt a further five minutes observation from the next point of cardiorespiratory arrest.

After five minutes of continued cardiorespiratory arrest confirm absence of:
  • Pupillary responses to light
  • Corneal reflexes
  • Motor response to supra-orbital pressure
The time of death is recorded as the time at which these criteria are fulfilled.


Brain stem death

‘Irreversible absence of brainstem function despite artificial maintenance of circulation and gas exchange’.

Preconditions
Apnoeic coma.
Irreversible structural brain damage caused by a disorder which can lead to brain death.

Exclusions
Primary metabolic or endocrine disturbance
Drug intoxication (inc sedatives)
Paralysis from NMBDs or neuromuscular disorder
Abnormal posturing or convulsions

Further Conditions
Drug levels:
  • Thiopentone levels < 5mg/dl
  • Midazolam levels < 10μg/L
Metabolic and CVS:
  • Temperature > 34°C
  • MAP > 60
  • CO2 < 6
  • O2 > 10
  • Ph 7.35 - 7.45
Electrolytes:
  • Sodium 115 -160
  • Potassium > 2
  • Magnesium > 0.5
  • Phosphate levels < 3
  • Glucose > 3

Necessary clinical findings on testing

Absent cranial nerve reflexes
Pupillary light
Corneal
Oculovestibular - slow injection of 50mls ice water into each ear over 1 min with head at 30 degrees to horizontal (unless spinal injury) with no eye movements observed.
Gag - posterior pharynx stimulation..
Cough - suction catheter down to carina
Absent motor responses in cranial nerve distribution to any peripheral stimuli.

Apnoea test:
The apnoea test should be the last brain-stem reflex to be tested and should not be performed if any of the preceding tests confirm the presence of brain-stem reflexes.
Increase FiO2 to 1.0
Check ABG to confirm that the measured PaCO2 and SaO2 correlate with the monitored values.
With oxygen saturation greater than 95%, reduce minute volume by lowering the respiratory rate to allow a slow rise in ETCO2.
Once ETCO2 rises above 6.0KPa, check ABG to confirm that PaCO2 > 6.0KPa and that the pH is < 7.40 (CO2 may need to rise to >6 to get pH <7.4).
If CVS stable, disconnect the patient from the ventilator and attached to an oxygen flow of 5L/min via an endotracheal catheter and observe for 5 mins. If adequate oxygenation proves difficult, then CPAP (and possibly a prior recruitment manoeuvre) may be used.
After 5 mins and no spontaneous respiratory response, confirm with ABG that CO2 has risen >0.5 from starting value.
No respiratory centre activity can be assumed and documented.
The ventilator should be reconnected and the minute volume adjusted to allow a gradual return of the blood gas concentrations to the levels set prior to the commencement of testing.

Who and when?
2 sets of tests by 2 doctors both registered for >5yrs. 1 must be a consultant.
Can be carried out together or separately.
No specific time interval between testing - just long enough to allow CO2 to return to normal is the minimum.
Time of death when 1st set of tests failed.

Limb and trunk movements due to spinal reflexes may still occur after brainstem death.