Karnataka PGET Medicine MCQ Answer 06

The correct answer is C

In many countries death is defined as the irreversible cessation of circulatory and respiratory functions or the irreversible cessation of all functions of the “entire brain, including the brain stem”. Brain death is defined as the irreversible cessation of the whole brain functions. In India (The Transplantation of Human Organ Act 1994) the law recognizes “brain stem” death as human death and it is defined based on irreversible cessation of brain stem functions. Japanese law introduces two alternative definitions for human death and gives opportunity to the individuals to choose the definition of death either traditional definition or brain-based definition based on their own views.

The testing of all the following is considered sufficient

1. Both pupils are fixed in diameter and do not respond to changes in the intensity of light.
   

2. Corneal reflex is absent in both eyes.
   

3. The vestibulo-ocular reflex is absent.
1. This is absent when no eye movement occurs in both eyes during or after the slow injection of at least 20ml of ice-cold water into at least one external auditory meatus, or preferably into each external auditory meatus in turn.
2. Clear access to the tympanic membrane should be established by direct inspection. This test may be contraindicated on one or other side by local trauma.
   

4. No motor responses within the cranial nerve distribution can be elicited by adequate painful stimulation of any somatic area.
   

5. There is no gag reflex.
   

6. There is no cough reflex.
   

7. Apnoea test should be done last. No respiratory movements occur when the patient is disconnected from the mechanical ventilator for long enough to ensure that the arterial carbon dioxide tension rises above the threshold for stimulating respiration.
1. The PaCO₂ must be greater than 8.0kPa and arterial pH less than 7.30. Blood-gas analysis must be available for this test to be performed. If the test is not available the patient must be moved to a facility where this test is routinely available.
2. These patients may be moderately hypothermic (35^oC-37^oC), flaccid, and with a depressed metabolic rate, so that PaCO₂ rises only slowly in apnoea (about 0.27kPa/min). They should be disconnected from the mechanical ventilator when their PaCO₂ is close to normal.
3. Hypoxaemia during disconnection should be prevented by preoxygenation and administration of oxygen during the test, e.g. by delivering oxygen through a catheter into the trachea.

The following observations are compatible with the diagnosis of brain death

1. Movements of limbs in response to a stimulus outside the distribution of cranial nerves.
2. Sweating, blushing, tachycardia.
3. Normal blood pressure without pharmacological support.
4. Absence of diabetes insipidus (normal osmolar control mechanism)
5. Deep tendon reflexes.
6. Extensor planter reflex.

Category: Karnataka PGET 2007 MCQs