10-23-2007, 06:27 PM
Unresponsiveness: The patient is completely unresponsive to external visual, auditory, and tactile stimuli and is incapable of communication in any manner.
Absence of cerebral and brain stem function: Pupillary responses are absent, and eye movements cannot be elicited by the vestibulo-ocular reflex or by irrigating the ears with cold water. The corneal and gag reflex are absent, and there is no facial or tongue movement. The limbs are flaccid, and there is no movement, although primitive withdrawal movements in response to local painful stimuli, mediated at a spinal cord level, can occur.
Apnea Test: An apnea test should be performed to ascertain that no respirations occur at a PCO2 level of at least 60 mmHg. The patient oxygenation should be maintained with giving 100% oxygen by a cannula inserted into endotracheal tube as the PCO2 rises. The inability to develop respiration is consistent with medullary failure.
Nature of coma must be know: Known structural disease or irreversible systemic metabolic cause that can explain the clinical picture. Some causes must be ruled out. Body temperature must be above 32 C to rule out hypothermia. No chance of drug intoxication or neuromuscular blockade. Patient is not in shock
Persistence of brain dysfunction; Six hours with a confirmatory isoelectric EEG or electrocerebral silence, performed according to the technical standards of the American Electroencephalographic Society OR Twelve hours without a confirmatory EEG OR Twenty-four hours for anoxic brain injury without a confirmatory isoeletric EEG
Confirmatory tests (are not necessary to diagnose brain death)
EEG with no physiologic brain activity
No cerebral circulation present on angiographic examination
Brain stem-evoked responses with absent function in vital brain stem structures
Absence of cerebral and brain stem function: Pupillary responses are absent, and eye movements cannot be elicited by the vestibulo-ocular reflex or by irrigating the ears with cold water. The corneal and gag reflex are absent, and there is no facial or tongue movement. The limbs are flaccid, and there is no movement, although primitive withdrawal movements in response to local painful stimuli, mediated at a spinal cord level, can occur.
Apnea Test: An apnea test should be performed to ascertain that no respirations occur at a PCO2 level of at least 60 mmHg. The patient oxygenation should be maintained with giving 100% oxygen by a cannula inserted into endotracheal tube as the PCO2 rises. The inability to develop respiration is consistent with medullary failure.
Nature of coma must be know: Known structural disease or irreversible systemic metabolic cause that can explain the clinical picture. Some causes must be ruled out. Body temperature must be above 32 C to rule out hypothermia. No chance of drug intoxication or neuromuscular blockade. Patient is not in shock
Persistence of brain dysfunction; Six hours with a confirmatory isoelectric EEG or electrocerebral silence, performed according to the technical standards of the American Electroencephalographic Society OR Twelve hours without a confirmatory EEG OR Twenty-four hours for anoxic brain injury without a confirmatory isoeletric EEG
Confirmatory tests (are not necessary to diagnose brain death)
EEG with no physiologic brain activity
No cerebral circulation present on angiographic examination
Brain stem-evoked responses with absent function in vital brain stem structures