Mollart and Goulon first coined the term 'coma depasse,' meaning a state beyond coma, for brain death. The Conference of Royal Medical Colleges in 1976 came to the consensus that brainstem death constitutes brain death. The revised memorandum in 1979 correlated brainstem death with death itself. The American Academy of Neurology (AAN) has postulated brain death as a “coma, absence of brainstem reflexes, and apnea.” Academy of Medical Royal Colleges Working Party has defined brainstem death as 'the irreversible loss of the capacity for gaining consciousness, and the capacity to spontaneously breathe.'
Persistent vegetative state- loss of only cortical functions with intact brain stem functions
Brain-stem death- absent brain stem reflexes but the presence of few cortical as well as hypothalamic integrity such as osmoregulation
Whole Brain death- biological death with absent cortical and brainstem functions
Death- Whole-brain death along with the cardiopulmonary arrest
However, following confounding factors that can impede upon correct evaluation of the brainstem function must first be ruled out:
If the patient fulfills the above criteria and evaluation reveals the absence of brainstem reflexes, the clinician should perform apnea testing per the AAN recommendation. 
The test is terminated in instances wherein there is hypotension, hypoxemia, or cardiac arrhythmias.
The absence of brainstem reflexes and an apnea test negative for spontaneous respirations validate the brain death of the patient.
Ancillary tests that can be used to diagnose brain death include:
These tests are only justified when apnea testing is inconclusive, or patients are too unstable to proceed with apnea testing, or when brainstem reflexes cannot be carried out (vestibulo-ocular reflex in cervical spine injuries).
Brainstem death is a clinical diagnosis made by an examiner. Ancillary tests are not essential for confirming brain death.
Brainstem death has to be certified by certified board members, which include:
Members from the organ donation or the transplantation team cannot be involved in this certification.
The clinical diagnosis of brain death should take place in three steps:
However, when planning for organ donation, separate complete examinations by two physicians is recommended.
Ethical morality - justifying the use of limited medical resources, adding up the financial burden, and maximizing emotional toll to relatives in a hopeless clinical scenario
The whole-brain death concept- It is more prudent for the application of brainstem death rather than the whole brain death concept. It requires emphasis that though the brain stem is dead, there may still be some cortical and the hypothalamic functions (osmoregulation) intact in the patient. It is also distinct from cortical death (persistent vegetative state) wherein the brainstem functions are intact.
Concerns with the apnea test- There are inherent confounding clinical factors that can invalidate the apnea test, such as hypoxia, hypotension, cervical cord injuries. Moreover, hypercarbia by causing cerebral vasodilation can further impede upon the cascade of impending cerebral herniation, thereby further complication the clinical scenario.
Public belief in brain death and organ procurement- There can be a significant concern among the relatives and the public that organ donation occurs when the patient heart is still beating, and the person is not entirely dead. There can be looming fear that death will be declared prematurely for the sake of organ and tissue retrieval.
The diagnosis of brain death is primarily derived clinically.
The first step in determining brainstem death is to notify the next of kin about the process.
The interval observation period of 6 hour period is usually considered sufficient in adults and children over one year age. A reliable interval period has not been established for children less than seven days old. For children between 7 days to two months, two examinations and electroencephalograms (EEGs) should be separated by at least 48 hours. In contrast, in children between two months to one year, two examinations and EEGs should be separated by at least 24 hours.
Repeat the clinical assessment of brain stem reflexes.
The steps and all examinations require full documentation.
Confirmatory testing should only take place out when deemed necessary and include:
Electroencephalography: absent electrical activity during at least 30 minutes of recording
Nuclear brain scan: the absence of uptake of isotope (“hollow skull phenomenon”)
Somatosensory evoked potentials: Brain death confirmed by the bilateral absence of N20-P22 response with median nerve stimulation.
Transcranial doppler ultrasonography: small systolic peaks confirm brain death in early systole without diastolic flow or reverberating flow.
Medical Record Documentation should include:
Etiology and irreversibility of coma
Absent motor response to pain
Absent brainstem reflexes during two separate examinations separated by at least 6 hours
Absent respiration with pCO2 greater than or equal to 60 mmHg
Justification for, and result of, confirmatory tests if applicable
Clinical instances that can be observed but compatible with the diagnosis of brain death :
Because of differences in the definition of death owing to different cultural and religious grounds, it is challenging to obtain equivocal consensus for declaring brainstem death. The diagnosis of brainstem death requires meticulous and verifiable testing and evaluation. In most intensive care settings the initial examination is performed by the critical care provider. The critical care nurse assists the clinician to make this diagnosis by verifying and documenting the neurological status of the patient before and during the brainstem evaluation. The critical care nurse also assists the medical team by monitoring the patient, especially during the apnea testing, to ensure the test is terminated if unstable vital signs develop. The bedside nurse, social worker, and the clinical providers can educate the family about the process of brainstem death evaluation and the meaning of the results to help the family understand this difficult concept. A collaborative interprofessional team can help accurately and efficiently diagnose the patient with brainstem death. This will help avoid unnecessary testing and provide timely family support when the diagnosis is confirmed. [Level 5]
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