A red flag for diagnosing brain death: decompressive craniectomy of the posterior fossa

Abstract

Purpose: Brain death/death by neurologic criteria (BD/DNC) may be determined in many countries by a clinical examination that shows coma, brainstem areflexia, and apnea, provided the conditions causing reversible loss of brain function are excluded a priori. To date, accounts of recovery from BD/DNC in adults have been limited to noncompliance with guidelines.

Clinical features: We report the case of a 72-yr-old man with a combined primary infratentorial (hemorrhagic) and secondary global (anoxic) brain lesion in whom decompressive craniectomy of the posterior fossa and six-hour therapeutic hypothermia (33-34°C) followed by 8-hour rewarming to ≥ 36°C were conducted. Thirteen hours later, clinical findings of brain function loss were documented in addition to guideline-compliant exclusion of reversible causes (arterial hypotension, intoxication, depressant drug effects, relevant metabolic or endocrine disequilibrium, chronic hypercapnia, neuromuscular disorders, and administration of a muscle relaxant). Since a primary infratentorial brain lesion was present, German guidelines required further ancillary testing. Doppler ultrasonography revealed some preserved cerebral circulation, and BD/DNC was not diagnosed. Approximately 24 hr after rewarming to ≥ 36°C, the patient exhibited respiratory efforts. He continued with assisted respiration until final asystole/apnea, without regaining additional brain function other than mild signs of hemispasticity. Follow-up computed tomography showed partial herniation of the cerebellum through the craniectomy gap of the posterior fossa, alleviating caudal brain stem compression.

Conclusions: Therapeutic decompressive craniectomy of the posterior fossa may allow for delayed reversal of apnea. In these patients, proof of cerebral circulatory arrest should be mandatory for diagnosing BD/DNC.

Keywords: Doppler ultrasonography; brain death; cerebellar hematoma; cessation of brain function; computed tomography angiography; electroencephalography.

Fig. 1

Diagram showing the timeline of core temperature and clinical events. Body core temperatures measured with a urinary bladder thermometer are displayed (•). The duration of medical measures/clinical events is shown by colored bands: targeted temperature management using a core cooling device (dark blue), administration of a cumulative dose of 13 mg·kg⁻¹ propofol iv (light green), administration of a cumulative dose of 0.50 µg·kg⁻¹ sufentanil iv (dark green), gradual rewarming to normothermia ≥ 36°C (light blue), clinical investigation and Doppler ultrasonography according to the guideline for diagnosing brain death (red), assisted spontaneous breathing (orange), and terminal asystole/apnea (black) (Color figure online).

Fig. 2

Cerebral computed tomography (CCT) findings 33.5 hr after cardiopulmonary resuscitation. A–C, F) Nonenhanced CCT images showing partial herniation of the cerebellum through the craniectomy gap of the posterior fossa (C: white arrow; F: black arrow), alleviating brain stem compression by some amount. D, E) Contrast-enhanced CT angiography, obtained with a standardized protocol for proof of cerebral circulatory arrest, contradicted arrest of cerebral circulation, with opacification of the left middle and anterior cerebral arteries (D), weak opacification of the right middle and anterior cerebral arteries (D), and weak opacification of the basilar artery (E; arrow) by the contrast medium.