I. Prerequisites for determination
1.Clear cause of coma.
2.Reversible coma of various causes is excluded.
Second, clinical determination
1. Deep coma.
2.Disappearance of brainstem reflexes.
3, no voluntary respiration: maintained by ventilator, no voluntary respiration confirmed by the voluntary respiratory excitation test.
All the above three must be present.
Confirmation test
1, Short latency somatosensory evoked potentials (SLSEP) of the median nerve showing the presence of N9 and/or N13 and the disappearance of P14, N18 and N20.
2. electroencephalogram (EEG) showing electrostatic resting.
3, transcranial Doppler ultrasound (TCD) showed oscillatory waves, small sharp systolic waves or loss of blood flow signal in the anterior and posterior intracranial circulation.
At least two of the above three are positive.
IV. Determination time
Brain death can be determined for the first time if both clinical judgment and confirmation test results meet the criteria for determining brain death. If the results still meet the criteria for determining brain death after 12 hours of the first determination, brain death can be finally confirmed.
1.Definition of brain death.
Brain death is the irreversible loss of whole brain function, including brain stem, i.e. death.
2.The prerequisites for determining brain death are
(1) The cause of coma is clear
Coma caused by primary brain injury includes craniocerebral trauma, cerebrovascular disease, etc.; coma caused by secondary brain injury is mainly due to cardiac arrest, anesthesia accident, drowning, asphyxia and other hypoxic encephalopathy. Those with unclear causes of coma cannot implement brain death determination.
(2) Excluding reversible coma of various causes
Including acute poisoning (such as carbon monoxide poisoning, alcohol poisoning, sedative-hypnotic poisoning, narcotic poisoning, antipsychotic poisoning, muscle relaxant poisoning, etc.), hypothermia (anal temperature ≤ 32℃), serious electrolyte and acid-base balance disorders, serious metabolic and endocrine disorders (such as hepatic encephalopathy, uremic encephalopathy, hypoglycemic or hyperglycemic encephalopathy), etc.
3.Clinical determination
(1) Deep coma.
Thumbs are strongly compressed on both sides of the patient’s supraorbital notch or pinprick the face respectively, and there should not be any facial muscle activity. The Glasgow Coma Scale (GCS) score is 3.
(2) Loss of brainstem reflexes.
If all five reflexes, such as pupil-to-light reflex, corneal reflex, cephalo-ocular reflex, vestibulo-ocular reflex and cough reflex, are absent, it can be judged that the brainstem reflex is absent. If there are items in the five brainstem reflexes that cannot be determined, additional confirmation test items should be added.
(3) Absence of voluntary respiration.
Brain dead people have no autonomic breathing and must rely on the ventilator to maintain ventilation, but to determine the cessation of autonomic breathing, in addition to the visual determination of the presence of respiratory movements in the chest and abdomen, it must also be verified by the autonomic respiratory excitation test.
4.Confirmation test.
The order of preference for confirmation tests is SLSEP, EEG, and TCD in that order.
At least 2 of the confirmation tests should meet the criteria for determining brain death.
5.Determination steps
In the first step, the clinical determination of brain death is performed, and those who meet the determination criteria will enter the next step.
In the second step, brain death confirmation test should be performed, and those who meet the criteria for brain death should enter the next step.
The third step is to conduct the brain death autonomic respiration stimulation test to verify the disappearance of autonomic respiration.
Brain death was confirmed when all the above three steps met the criteria for determining brain death.