Mechanisms underlying neurocognitive dysfunction following critical illness: a systematic review

Area of Science:

• Neuroscience
• Critical Care Medicine
• Public Health

Background:

• Cognitive impairment is a global health issue affecting over 150 million people.
• Survivors of critical illness frequently experience long-term neurocognitive dysfunction, with unclear underlying mechanisms.

Purpose of the Study:

• To systematically review and synthesize evidence on potential mechanisms of neurocognitive dysfunction after critical illness.
• To guide future research directions for understanding and addressing this post-critical illness complication.

Main Methods:

• A systematic literature search was conducted for studies published between January 1974 and July 2023.
• Included studies focused on adult critical illness survivors, assessed cognitive impairment, and explored causative mechanisms.
• Study quality and risk of bias were evaluated using the Newcastle-Ottawa scale.

Main Results:

• 37 studies involving 4344 patients were included, with most being single-center and having small sample sizes.
• Long-term cognitive impairment prevalence ranged from 13% to 100% among patients.
• Increased inflammatory cytokines and white matter hyperintensities were the most commonly reported associations with reduced cognition.

Conclusions:

• The pathophysiology of post-critical illness neurocognitive decline remains incompletely understood.
• Mechanisms implicated in neurodegenerative conditions suggest a potential accelerated aging process.
• Large-scale studies are essential to fully elucidate the causes of neurocognitive dysfunction in critical illness survivors.