Cortical death __ whole brain death.pptx

Seminar for forensic medicine

1. Cortical Death And Whole Brain Death

2. Death Thanatology- (Gk Thanatos, the God of Death) is that branch of science that studies death in all its aspects. S.46 IPC- death denotes death of a human being unless the contrary appears from the context. Registration Of Births And Deaths Act, Sec. 2(b)- defines death as permanent disappearance of all evidence of life at any time after livebirth has taken place. Types of death Somatic death- it is complete any irreversible stoppage of the circulation, respiration and brain functions, but there is no legal definition of death Molecular death- it means the death of cells and tissues individually, which takes place usually one or two hours after the stoppage of the vital functions.

3. The Moment Of Death Death is not an event, it is an process. Historically ( medically and legally) the concept of death was that of ‘heart and respiration death’, i.e. spontaneous stoppage of heart and lung functions. However have changed this medically in favour of a new concept of ‘brain death’ , that is, irreversible loss of cerebral function.

4. Brain Death It is of three types- Cortical or cerebral death Brain stem death Whole brain death

5. Cortical Death Cortical or cerebral death with an intact brain stem. This produces a vegetative state in which respiration continues, but there is total loss of power of perception by the senses. It involves the irreversible destruction of the cerebral cortex while the brainstem and other vital functions may be still be intact. This state of deep coma can be produced by cerebral hypoxia, toxic conditions or widespread brain injury.

6. Whole Brain Death Whole brain death that is permanent cessation of functions of cerebrum, cerebellum and brain stem. Brain stem- the tissue in the floor of the aqueduct, between the third and fourth ventricles of the brain contains ascending reticular activating system. Which extends throughout the brainstem from the spinal cord to the subthalamus, determines arousal. Damage to the ascending reticular activating substance or damage to areas of the cerebral hemispheres results in disturbance in normal consciousness. If this area is death, the person is irreversibly unconscious and apnoeic ( incapable of breathing).

7. Functions Of Brain Stem A properly functioning paramedian tegmental area of the brain stem is a precondition for full consciousness which enables the cerebral hemispheres to work in an integrated way. Lesions of this part are associated with profound coma. The brain stem is also responsible for the respiratory drive, and in large measure (but not exclusively) for the maintenance of blood pressure. All motor output from the brain travel through the brainstem. Apart from vision and smell, all the sensory traffic coming into the brain arrives through the brainstem. The brainstem also mediates the cranial nerve reflexes.

8. Various Criteria For Determining Brain Death Philadelphia protocol (1969) – It determined death on the basis of (a ) lack of responsiveness to internal and external environment. Absence of spontaneous breathing movements for 3 mins, in the absence of hypocarbia and while breathing room air. No muscular movements with generalized flaccidity and no evidence of postural activity or shivering Reflexes and responses (a) pupils fixed, dilated, and non reactive to strong stimuli. (b) absence of corneal reflexes (c) supraorbital or other pressure responses absent (both pain response and decerebrate posturing). (d) absence of snouting and sucking responses. (e) no reflex response to upper and lower airway stimulation. (f) no ocular response to ice-water stimulation of inner ear (g) no superficial and deep tendon reflexes. (h) no plantar responses. Falling arterial pressure without support by drugs or other means. Isoelectric EEG (in the absence of hypothermia, anaesthetic deaths, and drug intoxication) recorded spontaneously during auditory and tactile stimulation.

9. These criteria shall have been present for at least 2 hours and two physicians other than the physician of a potential organ recipient should certify death. As the protocol insists on a two hour delay, this precludes the use of any organs for transplantation.

10. Harvard criteria of Brain Death (1968) In 1968 the Harvard Criteria of the moment of death were developed. Laid stress on determining the activity of only the brain to determine death. The criteria suggested that the activity of the heart and lung are important not by themselves, but as a sign of brain activity

11. Harvard Criteria Of The Moment Of Death

12. Unreceptivity and unresponsivity The patient is totally unaware of the externally applied stimuli (unreceptivity). Even the most intensely painful stimuli evoke no vocal or other response, not even a groan, withdrawal of a limb, or quickening of respiration (unresponsivity). No movements or breathing There should be no spontaneous muscular movements, or any breathing movements for at least one continuous hour. The breathing movements are to be observed by turning off the respirator for 3 minutes and observing closely whether there is any effort on the part of subject to breathe spontaneously. No reflexes The pupil should be fixed and dilated, and unresponsive to bright light. Ocular movement [to head turning and to irrigation of the ears with ice water] should be absent. Corneal and pharyngeal reflexes are absent. Spinal reflexes [e.g. knee jerk] are also absent

13. Flat electro-encephalogram Flat or iso-electric EEG [at 5µV/mm] is of great confirmatory value. Repetition of tests All tests should be repeated again after 24 hours with no change. Respirator must be put back on during the intervening period. It can only be taken off after the patient has been declared dead. This was done to offer legal protection to physicians, otherwise, it could be argued that they turned off respirator on a living patient

14. Minnesota criteria of Brain stem death (1971) No spontaneous movement No spontaneous respiration when tested for a period of 4 minutes at a time Absence of 5 major brain stem reflexes. EEG not mandatory. All the above findings must remain unchanged for at least 12 hours.

15. Differences Between 2 Major Criteria Of Death

16. Indian Law On Brain Stem Death S.2(d) of The Transplantation of Human Organs and Tissues Act, 1994. S.3(5) of the same Act - “where any human organ is to be removed from the body of a deceased person, the doctor must confirm that- life is extinct in such body or where it appears to be a case of brain-stem death, such death has been certified under section 3(6). S.3(6) of the same Act – Where any human organ is to be removed from the body of a person in the event of his brain-stem death, no such removal shall be undertaken unless such death is certified by a Board of medical experts consisting of ( i ) the registered medical practitioner, in charge of the hospital in which brain-stem death has occurred (ii) an independent specialist nominated by the doctor specified in clause [ i ] (iii) a neurologist or a neurosurgeon to be nominated by the registered medical practitioner specified in clause [ i ] and (iv) the registered medical practitioner treating the person whose brain-stem death has occurred .

17. Medico Legal Considerations Of Brain Death For legal and medical purposes, an individual who has sustained an irreversible cessation of functioning of brain, including the brain stem, is dead. A determination of death must be made in accordance with the criteria outlined earlier. Another aspect that deserves consideration is the criteria to be followed in switching of the heart-lung apparatus. Sustaining life by artificial maintenance of circulation and respiration inherits some legal implications. Considering the death to be a permanent and irreversible cessation of functions of the 3 independent vital systems of the body- the nervous, the circulatory and the respiratory systems- will not help in deciding as to when the artificial aids should be stopped as these systems are functionally inter-linked. It is obvious that artificial aids may be applied in the hope that natural circulation or respiration may be resumed after the aids are continued for sometime. But natural respiration may not be resumed even after the use of artificial aids for considerable periods. Therefore where lies the line of demarcation i.e. when the artificial aids to be stopped so that the doctor may not get involved in the offence of culpable homicide not amounting to murder or one of rush and negligent act, if he has removed the aids indiscriminately.

18. In such crucial affair, the decision for permanent withdrawal of the artificial aids should be preferably be taken after consultation with another doctor. Ordinarily, it is sufficient to wait for 10-15 minutes. If no evidence of spontaneous functioning of respiration /circulation is available for such a continuous period, the doctor(s) is/are justified in disconnecting the artificial aids because the serious permanent impairment of brain cells can occur with only 4-6 minutes of oxygen deprivation and total loss of function generally supervenes when the deprivation exceeds 10 minutes.

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