The effect of Ketamine on brain the Ketamine is traditionally considered to increase cerebral blood flow and CMRO2 however, positron emission tomography shows that subanesthetic doses of racemic ketamine increase cerebral blood flow with a minor increase in regional CBV but do not affect oxygen consumption significantly.
The most profound changes in regional CBF with Ketamine on brain were observed in structures related to pain processing. Langsjo et al have shown that there is relative increase in regional glucose metabolism rate in the frontal, temporal, and parietal cortices.
However, this increase is seemed to parallel Ketamine on brain induced increases in cerebral blood flow. Though 5-ketamine is considered to be neuroprotective, however, in another study, Langsjo et al reported an increase in whole brain CBF by 36.4% without any effect on whole brain CMRO2 or GMR with Sketamine.
Ketamine can be administered to anesthetized and mechanically ventilated patients with mildly increased ICP without adverse effect of Ketamine on brain in altering cerebral hemodynamics due to its features and advantages.
Prior administration of thiopental, propofol, diazepam, or midazolam has been shown to blunt ketamine induced increases in cerebral blood flow and ICP on patients who are at risk.
In mechanically ventilated preterm neonates, ante-fontanelle pressure decreases with effect of Ketamine on brain after administration of 2 mg/kg IV.
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