Induced barbiturate coma: methods for evaluation of patients.

Seven patients treated with deep sustained barbiturate narcosis to protect the brain and control intracranial hypertension underwent extensive monitoring. The epidural intracranial pressure (EDP) and arterial blood pressure (BP) were recorded continuously; serial records of the EEG, somatosensory evoked potential (SEP) and internal carotid artery (ICA) flow velocities by pulsed Doppler technique were obtained. Serum barbiturate levels leading to full suppression of the EEG did not change the central conduction time nor the configuration of the evoked responses. Monitoring the intracranial pressure (ICP), BP, and thereby, the cerebral perfusion pressure (CPP) gave valuable information on the patients' state and served as a guide for dosage and timing of barbiturate therapy, and facilitated supervision of adequate ventilation. Recording of EEG and SEP, monitoring of the CPP and ICA Doppler investigation offer prognostic information in these cases. When clinical deterioration occurs, these methods can predict and, in combination, give ample evidence for development of brain tamponade. Premature as well as unnecessarily deferred 4-vessel angiography, therefore, can be avoided.