Computerized Transverse Axial Tomography in Epilepsy

The effects of hypotension induced by trimethaphan (TMP) or nitroprusside (NTP) together with controlled hemorrhage on cerebral electrical activity, cerebrospinal fluid pressure and systemic circulatory and metabolic variables were measured in 10 mongrel dogs anesthetized with halothane (end-tidal, 0.88±0.03%). Induced hypotension was maintained at cerebral perfusion pressure of 45 mmHg for 45 min and then at 30 mmHg for 45 min. In 5 TMP dogs, there were signicant decreases in EEG-power and slowing of peak power frequency from the frontal area, but not from the occipital area. The cerebrospinal fluid pressure did not change significantly except for an increase during induction stage of hypotension. In 5 NTP dogs, there were no significant changes in EEG-power and peak power frequency throughout the study from both frontal and occipital areas, but cerebrospinal fluid pressure increased significantly. With both drugs, an increase in glucose, lactate and lactate pyruvate ratio, and a decrease in Pao_2 were more pronounced at 30 mmHg than 45mmHg. With NTP, there were sustained increases in lactate and lactate pyruvate ratio even after restoration of arterial pressure. The same magnitude and duration of decrease in cerebral perfusion pressure induced by either TMP or NTP produced different effects on cerebral and systemic function.

Epilesy

EEG