Delayed hippocampal damage in humans following cardiorespiratory arrest

TLDR

Animal studies show that transient ischemia leads to delayed death of vulnerable hippocampal neurons. The study examined postmortem brain tissue from patients with anoxic‑ischemic encephalopathy after cardiorespiratory arrest to determine whether delayed hippocampal injury occurs in humans. Patients who died within 18 h of arrest had minimal hippocampal damage, whereas those surviving ≥24 h exhibited severe injury in all examined regions, with the hippocampus showing the most pronounced time‑dependent increase, confirming delayed hippocampal damage in humans and indicating a potential therapeutic window.

Abstract

Transient ischemia in animals produces delayed cell death in vulnerable hippocampal neurons. To see if this occurs in humans, we reexamined brain slides from all patients with anoxic-ischemic encephalopathy and a well-documented cardiorespiratory arrest. Eight patients dying 18 hours or less after cardiac arrest had minimal damage in hippocampus and moderate damage in cerebral cortex and putamen. Six patients living 24 hours or more had severe damage in all four regions. The increase in damage with time postarrest was significant only in the hippocampus. Delayed hippocampal injury now documented in humans provides a target for possible therapy that can be initiated after cardiopulmonary resuscitation.