Historically, when it came to brain injury, ketamine had a bad rap. Much of that dogma was dispelled in the last decade, and ketamine is now frequently used as an induction agent in acute brain injury, especially traumatic brain injury, due to it’s favorable effects on haemodynamics.
However a new application of ketamine is now being explored - whether ketamine may be able to reduce secondary brain injury.
9. Potential benefits of Ketamine
• Sedative and analgesic sparing
• Alternative mechanism of action to GABA agonists
• Cardiovascular stability from infusion and bolus
• Potential for amelioration of excitotoxic secondary brain injury
Ketamine sedation in acute brain injury
11. • Repeated waves of Glutamate
mediated mass depolarisation of
cortical tissue
• Occur abundantly in
TBI/SAH/Ischaemic and
Haemorrhagic stroke
• Associated with poor outcome in
TBI
• Release high volumes of Glutamate
- ?vehicle of excitotoxic brain injury
• Cause tissue stress,
vasoconstriction, local
hypoglycaemia
Cortical Spreading Depolarisation
Dreier J (2011) The role of spreading depression, spreading depolarisation
and spreading ischaemia in neurological disease. Nature Medicine Vol. 17 (4) 439-447
18. • Ketamine sole anaesthetic agent in healthy volunteers
• PET scans
• Regional increase cerebral blood flow and net increase
• Regional increase CMRO2 - nil net increase
• Regional increase in GMR - nil net increase
Ketamine and cerebral haemo-dynamics
Ketamine sedation in acute brain injury
29. Ketamine in Brain Injury (KIBI)
• Pilot feasibility study - 1mg/kg/hr, safety efficacy, feasibility, ICP, auto regulation
• Multi-centre feasibility study
• Larger trial of sedatives in TBI and SAH