Determination of Brain Death

1. Determination of Brain Death Donn Dexter, MD, FAAN Douglas T. Miller Symposium April 29, 2011

2. Disclosures Full time physician at Luther-Midelfort Mayo Heath System, Eau Claire, Wisconsin. No financial relationships or interests that pertain to organ donation.

6. Outline • What is Brain Death? • How Do You Declare Brain Death? • Clinical Evaluation • Neurologic Evaluation • Apnea Test • Ancillary Tests • Conclusion

7. Determination of Brain Death • Uniform Determination of Death Act (UDDA). • An individual who has sustained either: 1) irreversible cessation of circulatory and respiratory function or 2) irreversible cessation of all function of the entire brain, including brain stem, is dead. • A determination of death must be made with acceptable medical standards.

8. Determination of Brain Death • The American Academy of Neurology (AAN) delineated the medical standards for brain death in 1995. • This practice parameter was reviewed in 2010 (Neurology 74, June 8, 2010).

9. Determination of Brain Death • Question for the 2010 AAN review: Are there patients who fulfill the criteria of brain death who recover brain function? • In adults, the recovery of brain function has not been reported after clinical declaration of brain death using the 1995 AAN brain death criteria.

10. Determination of Brain Death • Determination of Brain Death – 4 Steps 1) Establish irreversible and proximate cause of coma. 2) Achieve normal core temperature. 3) Achieve normal systolic blood pressure. 4) Perform neurologic examination.

11. The Clinical Evaluation • Establish Irreversible and Proximate Cause of Coma • Usually obvious. • Exclude drugs (including alcohol above legal limit). • No recent or persistent neuromuscular blocking agents (train of 4 twitches to nerve stimulation). • No severe electrolyte, acid-base, or endocrine disturbance (ABGs, lytes, chem panel).

12. The Clinical Evaluation (cont.) • Achieve Normal Core Temperature • Core body temperature > 36 degrees C. • Important for apnea test. • Warming blanket and warmed IV fluids may be required.

13. The Clinical Evaluation (cont.) • Achieve Normal Systolic Blood Pressure • Neurologic examination usually reliable with systolic BP > 100 mmHg. • UW-OPO requires systolic BP > 100 mmHg. • May require vasopressors to maintain adequate BP (dopamine and neosynephrine often preferred).

14. The Clinical Evaluation (cont.) • Perform Neurologic Examination • One examination is sufficient. • Examiner should be intimately familiar with brain death criteria. • Most commonly a critical care specialist, neurologist, or neurosurgeon. • Varies by state. Outside WI check with state statute.

15. The Neurologic Examination • Coma • No evidence of responsiveness. • No eye opening to noxious stimuli. • No motor response to noxious stimuli other than spinally mediated reflexes (may require expertise to distinguish).

16. The Neurologic Examination (cont.) • Absence of Brainstem Reflexes • No pupillary response to bright light (typically fixed @ 4-9 mm). • Absent corneal reflex. • Absent facial muscle movement to noxious stimulus. • Absent pharyngeal and tracheal reflexes (gag and deep suction).

17. The Neurologic Examination (cont.) • Absent Brainstem Reflexes (cont.) • Absent eye movements to oculocephalic testing (doll’s eyes test); integrity of cervical spine must be certain. • Oculovestibular testing (cold water calorics) – Head of bed 30 degrees, 50 mL ice water irrigation of each patent ear canal with 5 minutes observation and 5 minutes between tests.

18. The Apnea Test • Preconditions • Normothermia. • Systolic BP > 100 mm Hg. • Euvolemia (positive fluid balance). • Eucapnia (PaCO2 35-45 mmHg). • No evidence for CO2 retention (COPD, severe obesity, severe OSA).

19. The Apnea Test (cont.) • Preoxygenate for 10 minutes to PaO2 >200 mm Hg. • Reduce ventilation frequency to 10 bpm and PEEP to 5 cm H2O. • If pulse oximetry remains > 95%, check baseline ABG. • Disconnect ventilator and preserve oxygenation with 100% O2 @ 6-10 lpm via catheter through the ET at level of carina.

20. The Apnea Test (cont.) • Watch closely for respiratory movements (abdominal or chest excursions). • If no respiratory efforts, draw ABGs at 3-5 minutes and again at 7-10 minutes. • If arterial PaCO2 is 60 mm Hg or greater or if >20 mmHg over baseline, the test is positive. • If inconclusive, may extend to 10-15 minutes if clinically stable.

21. The Apnea Test (cont.) • Abort Apnea Test for: • Spontaneous respiratory effort. • Significant cardiac ectopy. • Pulse oximetry <90%. • Systolic blood pressure < 90 mmHg.

22. Ancillary Testing • EEG, TCD, CTA, MRI/MRA, cerebral angiography, and nuclear scans have all been used to confirm brain death. • Used when standard testing impossible or inconclusive (i.e. aborted apnea test). • EEG, cerebral angiography, and nuclear scan preferred.

23. Documentation • Follow checklist closely! • Time of death is the time PaCO2 reached target. • If apnea test aborted, the time of death is the time ancillary test is interpreted.

24. Conclusion • Have a clear and available protocol for the determination of brain death at your institution (UW-OPO has a good one). • Review it regularly; test it formally. • Follow it closely.