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Revising a dogma: ketamine for patients with neurological injury?
Sabine Himmelseher1, Marcel E Durieux
1*Klinik fuer Anaesthesiologie, Klinikum rechts der Isar, Technische Universität, München, Germany; and †Department of Anesthesiology, University of Virginia Health System, Charlottesville, Virginia.
Unlabelled:
We evaluated reports of randomized clinical trials in the perioperative and intensive care setting concerning ketamine's effects on the brain in patients with, or at risk for, neurological injury. We also reviewed other studies in humans on the drug's effects on the brain, and reports that examined ketamine in experimental brain injury. In the clinical setting, level II evidence indicates that ketamine does not increase intracranial pressure when used under conditions of controlled ventilation, coadministration of a gamma-aminobutyric acid (GABA) receptor agonist, and without nitrous oxide. Ketamine may thus safely be used in neurologically impaired patients. Compared with other anesthetics or sedatives, level II and III evidence indicates that hemodynamic stimulation induced by ketamine may improve cerebral perfusion; this could make the drug a preferred choice in sedative regimes after brain injury. In the laboratory, ketamine has neuroprotective, and S(+)-ketamine additional neuroregenerative effects, even when administered after onset of a cerebral insult. However, improved outcomes were only reported in studies with brief recovery observation intervals. In developing animals, and in certain brain areas of adult rats without cerebral injury, neurotoxic effects were noted after large-dose ketamine. These were prevented by coadministration of GABA receptor agonists.
Implications:
Ketamine can be used safely in neurologically impaired patients under conditions of controlled ventilation, coadministration of a {gamma}-aminobutyric acid receptor agonist, and avoidance of nitrous oxide. Its beneficial circulatory effects and preclinical data demonstrating neuroprotection merit further animal and patient investigation.
Insights
Ketamine is safe for neurologically impaired patients when administered with controlled ventilation and specific co-therapies. This anesthetic may improve cerebral perfusion and offers neuroprotective benefits, warranting further study.
Area of Science:
- Neuroscience
- Anesthesiology
- Critical Care Medicine
Background:
- Ketamine's effects on the brain in patients with neurological injury are under investigation.
- Understanding ketamine's safety and efficacy in neurocritical care is crucial.
Purpose of the Study:
- To evaluate ketamine's effects on the brain in patients with or at risk for neurological injury.
- To review clinical and experimental data on ketamine's neurobiological impact.
Main Methods:
- Systematic review of randomized clinical trials in perioperative and intensive care settings.
- Inclusion of human studies on ketamine's brain effects and experimental brain injury models.
Main Results:
- Level II evidence suggests ketamine does not increase intracranial pressure under controlled ventilation with GABA agonist coadministration and without nitrous oxide.
- Ketamine may improve cerebral perfusion due to hemodynamic stimulation, potentially benefiting patients post-brain injury.
- Preclinical studies show ketamine possesses neuroprotective and S(+)-ketamine neuroregenerative effects, even when given post-insult.
Conclusions:
- Ketamine is safe for neurologically impaired patients under specific conditions (controlled ventilation, GABA agonist, no nitrous oxide).
- Its hemodynamic and neuroprotective properties suggest potential as a preferred agent in brain injury settings.
- Further animal and patient research is warranted to explore ketamine's benefits.
