The effect of
barbiturate coma upon regional cerebral blood flow (RCBF) and ultimate neurologic outcome was examined after total
cerebral ischemia (TCI). TCI was induced in dogs using a relatively noninvasive double-occlusion balloon technique; cardiopulmonary protection was provided during the period of
ischemia. RCBF was measured using 15-mu radioactively labeled
microspheres. A reproducible pattern of impaired reperfusion of the central nervous system (CNS) was observed in control animals after the restoration of cerebral perfusion pressure after TCI. This pattern was accentuated by the administration of
pentothal to induce
barbiturate coma. The additional depression in RCBF in those animals receiving
pentothal was most prominent in cortical gray matter and brainstem structures at 3 and 6 h after TCI. It was also observed in cortical white matter. No untreated animal surviving TCI achieved a neurologic functional level better than persistent vegetative (decerebrate) survival over 1 wk of observation. Animals receiving 90 mg/kg
body weight of
pentothal post-TCI demonstrated irreversible
cardiogenic shock related to the
myocardial depressant effect of the
drug. Animals receiving 40 to 60 mg/kg of
pentothal post-TCI demonstrated a survival rate similar to that of untreated animals. Although this study did not establish the possible effectiveness of
barbiturate coma in improving residual neurologic damage after TCI, the data do demonstrate that any possible effectiveness in this model is not associated with any improvement in the markedly decreased cerebral perfusion after TCI.