Abstract
Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, introduced into clinical practice
six decades ago, has often been the worst fear of a neuroanesthesiologist due to its
concerns of causing a rise in intracranial pressure and increasing cerebral blood
volume. However, the recent literature clarifies that it may have a beneficial role,
even in neurosurgical patients, because of its propensity to cause neuroprotection
through antiglutamatergic action on the NMDA receptors in the ischemic brain. Apart
from having an anticonvulsive role in refractory status epilepticus, its inherent
property of increasing blood flow to the ischemic areas offers protection to the penumbral
zone, thus preventing secondary brain injuries. Also, it has been widely used as an
analgesic at subanesthetic doses post spine surgeries. Recently, enough scientific
evidence has been published in favor of ketamine establishing the fact that it does
not cause a rise in intracranial pressure when the patient is mechanically ventilated
and normocarbia is maintained. It has also been used during evoked potential monitoring
as it amplifies signals even under general anesthesia and proves to be quite effective
during neuromonitoring. However, its adverse effects of increasing muscle tone, excessive
salivation, emergence delirium, agitation, and “out of body” experiences with long-term
psychomimetic effects and potential to cause addiction have precluded its widespread
use.
This review on ketamine summarizes the benefits of using it in neurosurgical anesthesia
with the aim of removing the fears we had in the past, which did not seem to be evidence
based.
Keywords
N-methyl-D-aspartate antagonist - excitotoxicity - neuroprotection - neuroinflammation
