[Energy and amino acid metabolism in the human brain under Disoprivan anesthesia with various paCO2 values].

Propofol like thiopental and etomidate, suppresses cortical electrical activity in a dose-related manner, which leads to a 36% decrease in cerebral oxygen uptake and a 51% decrease in cerebral blood flow after an induction dose of 2 mg/kg followed by a maintenance dose of 0.2 mg/kg per min. In this study, the effects of propofol and varying paCO2 values on cerebral energy and amino acid metabolism were examined. METHODS. Eleven male patients between 49 and 63 years of age who were about to undergo coronary artery bypass surgery were studied. Measurements were performed with the patient awake (I), during steady-state maintenance anesthesia after propofol 2 mg/kg as an induction dose with 0.2 mg/kg per min by infusion with normocapnia (paCO2 39.9 +/- 3.1 mm Hg) (II), during hypocapnia (paCO2 29.9 +/- 2.6 mmHg) (III), and during hypercapnia (paCO2 50.6 +/- 3.3 mmHg) (IV). Cerebral blood flow was measured using the argon wash-in technique. A catheter was advanced into the superior bulb of the right internal jugular vein for measurement of cerebral oxygen, glucose, lactate, and amino acid uptake and release, which were calculated by multiplying the arterial-cerebral venous oxygen and substrate difference by the cerebral blood flow. Lactate/glucose index was calculated from the equation. Formula: see text. where a-vD lactate and a-vD glucose represent the arterial-cerebral venous substrate differences in mmol/l. Cerebral electrical activity was recorded by Fourier analysis of the EEG.(ABSTRACT TRUNCATED AT 250 WORDS)