LACTATE AND EXCITATORY AMINO-ACIDS MEASURED BY MICRODIALYSIS ARE DECREASED BY PENTOBARBITAL COMA IN HEAD-INJURED PATIENTS

Primary traumatic brain injury and secondary ischemic/hypoxic injury a re being increasingly characterized at the neurochemical level. Neuroc hemical monitoring using microdialysis has shown that these forms of t issue damage share many common features. In particular, anaerobic glyc olysis with increased lactate production and release of excitatory ami no acids into the extracellular space are seen in both conditions. Cli nical microdialysis studies have heretofore focused on methodological issues, establishment of basal analyte values, and clinico-neurochemic al correlation. Here we report the neurochemical consequences of thera peutic intervention in head injury. Specifically, induction of thiopen tal coma to manage severe increased intracranial pressure in seven pat ients was associated with a 37% reduction of lactate, 59% reduction of glutamate, and 66% reduction in aspartate in the extracellular space of the brain.