Diagnosis of death
Patients frequently present to the emergency department in severe distress and expire, making diagnosis of death a critical skill for the EM physician. Pronouncing a patient dead has historically changed as medical technology has advanced, requiring more clarification. The definition or classification of death can also change based on the setting the patient is present in as well. For example in a mass casualty setting triaging a patient as "black" or dead, is done purely on the basis of responsiveness and spontaneous circulation and ventilation.  Interestingly there is not much training within medical education about pronouncing patients early in medical training, where one study cites only 30% of new interns know what is needed for pronunciation.  There is also significant pressure and weight on getting this final diagnosis right, and so missing any other potential etiologies that may masquerade as death is high stakes.
Note there is a distinction between pronouncing and certifying death. The former means assessing the patient and diagnosing death, whereas certifying death typically involves stating the cause of death as well.
- Brain death
- Drug overdose
- Persistent Vegetative State
- Electrolyte derangement
- Acidosis or Alkalosis
- Evaluation of the patient depends on the clinical setting the patient is in, as above, triage in settings of mass casualty changes the evaluation of death.
- The two main categories for diagnosis of death are cardiorespiratory and neurological.
- Cardiorespiratory: No spontaneous respiratory effort accompanied with 5 minutes of asystole- causing inadequate cerebral perfusion for long enough to cause neurologic compromise.
- Neurological: Two separate doctors must successfully declare the patient brain dead, preferably physicians skilled in neurological management, i.e. a neurologist or neurosurgeon.
- Patient in question needs to be uncoscious, apneic , and artificially ventilated.
- Clear etiology of severe brain injury.
- Consider all reversible causes of coma (differential above)
- Test brainstem reflexes, and demonstration they are absent
- Apnea testing 
Take care to acknowledge family needs.
- Tintinalli's Emergency Medicine