Dr kiran Resident in Neurology

1. DEPARTMENT OF NEUROLOGY OSMANIA MEDICAL COLLEGE Dr kiranResident in Neurology

2. American Academy of Neurology Guideline Update 2010 Determining BRAIN DEATH in Adult

3. Coma, from the Greek ‘‘deep sleep or trance,’’ is a state of unresponsiveness in which the patient lies with eyes closed and cannot be aroused to respond appropriately to stimuli even with vigorous stimulation.

4. Three medical considerations emphasize the importance of the concept of brain death: (1) Transplant programs require the donation of healthy peripheral organs for success. The early diagnosis of brain death before the systemic circulation fails allows the salvage of such organs. However, ethical and legal considerations demand that if one is to declare the brain dead, the criteria must be clear and unassailable

5. (2) Even if there were no transplant programs, the ability of modern medicine to keep a body functioning for extended periods often leads to prolonged, expensive, and futile procedures accompanied by great emotional strain on family and medical staff.

6. (3) Critical care facilities; are limited and expensive and inevitably place a drain on other medical resources. Their best use demands that one identify and select patients who are most likely to benefit from intensive techniques, so that these units are not overloaded with individuals who can never recover cerebral function.

7. The THREE clinical findings necessary to confirm irreversible cessation of all functions of the entire brain, including the brain stem: 1. coma (with a known cause) 2. absence of brainstem reflexes, and 3. apnea.

8. 4 Steps in Determining Brain Death • The Clinical Evaluation • The Neurologic Assessment • Ancillary Test • Documentation

9. The Clinical Evaluation A. Establish irreversible and proximate cause of coma. • Exclude the presence of a CNS-depressant drug effect • There should be no recent administration or continued presence of neuromuscular blocking agents • There should be no severe electrolyte, acid-base, or endocrine disturbance

10. The Clinical Evaluation B. Achieve normal core temperature. • Raise the body temperature and maintain a normal or near-normal temperature-36°C

11. The Clinical Evaluation C. Achieve normal systolic blood pressure. • Neurologic examination is usually reliable with a systolic blood pressure 100 mm Hg.

12. The Clinical Evaluation D. Perform 1 neurologic examination • If a certain period of time has passed since the onset of the brain insult to exclude the possibility of recovery, 1 neurologic examination should be sufficient to pronounce brain death.

13. 4 Steps in Determining Brain Death • The Clinical Evaluation • The Neurologic Assessment

14. The Neurologic Assessment A. Coma • Patients must lack all evidence of responsiveness. • Eye opening or eye movement to noxious stimuli is absent. • Noxious stimuli should not produce a motor response other than spinally mediated reflexes.

15. The Neurologic Assessment B. Absence of Brain Stem Reflex • Absence of pupillary response to a bright light is documented in both eyes. • Absence of ocular movements using oculocephalic testing and oculovestibular reflex testing. • Absence of corneal reflex. • Absence of facial muscle movement to a noxious stimulus. • Absence of the pharyngeal and tracheal reflexes.

16. The Neurologic Assessment C. Apnea • Absence of a breathing drive. • Breathing drive is tested with CO2 Challenge. • Prerequisites: 1) normotension 2) normothermia, 3) euvolemia 4) eucapnia (PaCO2 35–45 mm Hg) 5) absence of hypoxia 6) no prior evidence of CO2 retention

17. The CO2 Challenge • Adjust vasopressors to a systolic blood pressure 100 mm Hg. • Preoxygenate for at least 10 minutes with 100% oxygen to a PaO2 200 mm Hg. • Reduce ventilation frequency to 10 breaths per minute to eucapnia. • Reduce positive end-expiratory pressure (PEEP) to 5 cm H2O • If pulse oximetry oxygen saturation remains 95%, obtain a baseline blood gas

18. The CO2 Challenge • Disconnect the patient from the ventilator. • Preserve oxygenation(e.g., place an insufflation catheter through the endotracheal tube and close to the level of the carina and deliver 100% O2 at 6L/min). • Look closely for respiratory movements for 8–10 minutes. • Abort if systolic blood pressure decreases to 90 mm Hg. • Abort if oxygen saturation measured by pulse oximetry is 85% for 30 seconds.

19. The CO2 Challenge • If no respiratory drive is observed, repeat blood gas after 8 minutes. • If respiratory movements are absent and arterial PCO2 is 60 mm Hg (or 20 mm Hg increase in arterial PCO2 over a baseline normal arterial PCO2), the apnea test result is POSITIVE. • If the test is inconclusive but the patient is hemodynamically stable during the procedure, it may be repeated for a longer period of time (10–15 minutes) after the patient is again adequately preoxygenated.

20. 4 Steps in Determining Brain Death • The Clinical Evaluation • The Neurologic Assessment • Ancillary Test

21. Ancillary Tests • In clinical practice, EEG, cerebral angiography, nuclear scan, TCD, CTA, and MRI/MRA are currently used ancillary tests in adults. • Ancillary tests can be used when uncertainty exists about the reliability of parts of the neurologic examination or when the apnea test cannot be performed.

22. “In adults, ancillary tests are not needed for the clinical diagnosis of brain death and cannot replace a neurologic examination.”

23. 4 Steps in Determining Brain Death • The Clinical Evaluation • The Neurologic Assessment • Ancillary Test • Documentation

24. Documentation • Time of death is the time the arterial PCO2 reached the target value (60). • In patients with an aborted apnea test, the time of death is when the ancillary test has been officially interpreted.

25. Mechanism of Cerebral Death ICP>MAP is incompatible with life Increased Intracranial Pressure

27. Conditions Distinct From Brain Death • Persistent Vegetative State • Locked-in Syndrome • Minimally Responsive State

28. Persistent Vegetative State • Normal Sleep-Wake Cycles • No Response to Environmental Stimuli • Diffuse Brain Injury with Preservation of Brain Stem Function

29. Minimally Responsive State Static Encephalopathy • Diffuse or Multi-Focal Brain Injury • Preserved Brain Stem Function • Variable Interaction with Environmental Stimuli

30. Locked-in Syndrome Ventral Pontine Infarct • Complete Paralysis • Preserved Consciousness • Preserved Eye Movement

32. Brain Death Neurological Examination Clinical Prerequisites: • Known Irreversible Cause • Exclusion of Potentially Reversible Conditions • Drug Intoxication or Poisoning • Electrolyte or Acid-Base Imbalance • Endocrine Disturbances • Core Body temperature > 32° C

33. Brain Death Neurological Examination • Coma • Absent Brain Stem Reflexes • Apnea

34. Coma No Response to Noxious Stimuli • Nail Bed Pressure • Sternal Rub • Supra-Orbital Ridge Pressure

35. Absence of Brain Stem Reflexes • Pupillary Reflex • Eye Movements • Facial Sensation and Motor Response • Pharyngeal (Gag) Reflex • Tracheal (Cough) Reflex

36. Pupillary Reflex Pupils dilated with no constriction to bright light

37. Eye Movements Occulo-Cephalic Response “Doll’s Eyes Maneuver”

39. Eye Movements Oculo-Vestibular Response “Cold Caloric Testing”

41. Facial Sensation and Motor Response • Corneal Reflex • Jaw Reflex • Grimace to Supraorbital or Temporo-Mandibular Pressure

42. Apnea Testing Prerequisites • Core Body Temperature > 32° C • Systolic Blood Pressure ≥ 100 mm Hg • Normal Electrolytes • Normal PCO2

43. Apnea Testing 1. Pre-Oxygenation • 100% Oxygen via Tracheal Cannula • PO2 = 200 mm Hg 2. Monitor PCO2 and PO2 with pulse oximetry 3. Disconnect Ventilator 4. Observe for Respiratory Movement until PCO2 = 60 mm Hg 5. Discontinue Testing if BP < 90, PO2 saturation decreases, or cardiac dysrhythmia observed

44. Confounding Clinical Conditions • Facial Trauma • Pupillary Abnormalities • CNS Sedatives or Neuromuscular Blockers • Hepatic Failure • Pulmonary Disease

45. Observations Compatible with Brain Death • Sweating, Blushing • Deep Tendon Reflexes • Spontaneous Spinal Reflexes- Triple Flexion • Babinski Sign

46. Confirmatory Testing Recommended when the proximate cause of coma is not known or when confounding clinical conditions limit the clinical examination

47. Confirmatory Testing EEG Normal Electrocerebral Silence

48. Confirmatory Testing Cerebral Angiography Normal No Intracranial Flow

49. Confirmatory Testing Technetium-99 Isotope Brain Scan