The electroencephalogram in the determination of brain death

Taking the pulse of brain death: A meta-analysis of the natural history of brain death with somatic support

BACKGROUND AND PURPOSE

The conceptualization of brain death (BD) was pivotal in the shaping of judicial and medical practices. Nonetheless, media reports of alleged recovery from BD reinforced the criticism that this construct is a self-fulfilling prophecy (by treatment withdrawal or organ donation). We meta-analyzed the natural history of BD when somatic support (SS) is maintained.

METHODS

Publications on BD were eligible if the following were reported: aggregated data on its natural history with SS; and patient-level data that allowed censoring at the time of treatment withdrawal or organ donation. Endpoints were as follows: rate of somatic expiration after BD with SS; BD misdiagnosis, including "functionally brain-dead" patients (FBD; i.e. after the pronouncement of brain-death, ≥1 findings were incongruent with guidelines for its diagnosis, albeit the lethal prognosis was not altered); and length and predictors of somatic survival.

RESULTS

Forty-seven articles were selected (1610 patients, years: 1969-2021). In BD patients with SS, median age was 32.9 years (range = newborn-85 years). Somatic expiration followed BD in 99.9% (95% confidence interval = 89.8-100). Mean somatic survival was 8.0 days (range = 1.6 h-19.5 years). Only age at BD diagnosis was an independent predictor of somatic survival length (coefficient = -11.8, SE = 4, p < 0.01). Nine BD misdiagnoses were detected; eight were FBD, and one newborn fully recovered. No patient ever recovered from chronic BD (≥1 week somatic survival).

CONCLUSIONS

BD diagnosis is reliable. Diagnostic criteria should be fine-tuned to avoid the small incidence of misdiagnosis, which nonetheless does not alter the prognosis of FBD patients. Age at BD diagnosis is inversely proportional to somatic survival.

Analytic Reviews : The Diagnosis of Brain Death in the Adult Patient

The biological tenet upon which brain death is founded is absolute. The brain's inability to undergo cellular divi sion ensures that once individual neurons die they can not be replaced. Extrapolating this to the total brain, once the entire brain is dead no recovery can occur, and the patient's family can be guaranteed of that fact. The clinician, therefore, is faced primarily with a diagnostic challenge in determining that brain death is indeed pres ent. The components, procedures, and limitations of that diagnostic process in the adult patient are the sub jects of this discussion.

Prognosis of deeply comatose patients on ventilators

Although the concept of brain death has been widely accepted, the criteria required for making the diagnosis remain controversial. This prospective study was undertaken to examine the reliability of a set of clinical criteria adopted in Taiwan. One hundred and forty deeply comatose patients (101 men, 39 women; mean age 49.5 (SD 17.6) years) requiring ventilation were studied. Seventy three patients met the clinical criteria for brainstem death; all developed cardiac asystole (97% within seven days) despite continued full cardiorespiratory support. Brainstem death was diagnosed in only two of the 21 patients with hypoxic or ischaemic insults. This stresses the rarity of hypoxic or ischaemic encephalopathy as a cause of brainstem death. The results show that if strict attention is paid to preconditions and exclusions, brainstem death can be reliably diagnosed on clinical grounds alone.