26 Aug 08

Chronic “brain death”

Posted in Brain death at 20:42 by Laci

By D A Shewmon

Neurology 1998;51:1538-1545

One rationale for equating “brain death” (BD) with death is that it reduces the body to a mere collection of organs, as evidenced by purported imminence of asystole despite maximal therapy. To test this hypothesis, cases of prolonged survival were collected and examined for factors influencing survival capacity.

Formal diagnosis of BD with survival of 1 week or longer. More than 12,200 sources yielded approximately 175 cases meeting selection criteria; 56 had sufficient information for meta-analysis. Diagnosis was judged reliable if standard criteria were described or physicians made formal declarations. Data were analyzed by means of Kaplan-Meier curves, with treatment withdrawals as “censored” data, compared by log-rank test.

Survival probability over time decreased exponentially in two phases, with initial half-life of 2 to 3 months, followed at 1 year by slow decline to more than 14 years. Survival capacity correlated inversely with age. Independently, primary brain pathology was associated with longer survival than were multisystem etiologies. Initial hemodynamic instability tended to resolve gradually; some patients were successfully discharged on ventilators to nursing facilities or even to their homes.

The tendency to asystole in BD can be transient and is attributable more to systemic factors than to absence of brain function per se. If BD is to be equated with death, it must be on some basis more plausible than loss of somatic integrative unity.

18 Mar 07

When is dead really dead – on the legitimacy of using neurologic criteria to determine death

Posted in Brain death at 9:56 by Laci

By L M Whetstine

Critical Care 2007, 11:208

This review explores the legitimacy of the whole brain death (WBD) criterion. I argue that it does not fulfill the traditional biologic definition of death and is, therefore, an unsound clinical and philosophical criterion for death. I dispute whether the clinical tests used to diagnose WBD are sufficient to prove all critical brain functions have ceased, as well as examine the sets of brain functions that persist in many WBD patients. I conclude that the definition of death must be modified from a biologic to an ontologic model if we intend to maintain the WBD criterion.

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