Intracranial electroencephalographic changes in deep anesthesia.

OBJECTIVE: It is well known that electroencephalograms (EEGs) show electrical silence in deep anesthesia as well as brain death. This is the first report on intracranial EEG changes in deep anesthesia. METHODS: We developed a new direct brain monitoring system capable of recording intracranial EEGs. This study included 13 patients with head trauma or cerebrovascular accident under deep anesthesia. RESULTS: The intracranial EEGs showed different patterns of wave activity in depth compared with the cortical surface. In 3 of the cases, the scalp EEG showed a flat tracing at 2.0-2.5% of isoflurane. In two of the cases, the intracranial EEGs showed electrical silence when the scalp EEG was flat. Decreasing the concentration of isoflurane to 1.5%, the intracranial EEG showed single paroxysmal appearance of 'revival' theta waves on the electrocorticogram (ECoG) or electroventriculogram (EVG). The intracranial 'revival' wave was followed by high-voltage burst-waves. In another case, at 2.0-2.5% of isoflurane, the amplitude of the waves was greatest on the EVG. CONCLUSION: There is wave activity difference in the brain depth, which the scalp EEG is unable to show. Intracranial EEGs are able to show the first signs of revival after a nearly flat tracing in deep anesthesia.

[Isoflurane anesthesia with combined use of low dose fentanyl for open heart surgery].

The hemodynamic and respiratory effects of high dose fentanyl anesthesia and those of isoflurane anesthesia with combined use of low dose fentanyl were compared in 40 patients undergoing open heart surgery. Twenty patients (Group Fen) were anesthetized with high dose fentanyl (about 100 micrograms.kg-1), other twenty patients (Group Iso) were anesthetized with isoflurane (inhalation of 1.0-2.0%) combined with low dose fentanyl (about 8 micrograms.kg-1). Between the two groups, there were no significant differences in HR, CI, SVI, MPAP, MRAP, PVRI, RVCWI, LVSWI, DO2I, SvO2, and P/F ratio. In group Iso, there were significant decreases in mean arterial pressure (MAP) and systemic vascular resistance index (SVRI) at the time of sternotomy and before the cardiopulmonary bypass. In group Fen, a significant increase in VO2I occurred at the time of sternotomy. In ICU, catecholamine concentrations were significantly lower, and the duration of its use was significantly shorter in group Iso. Group Iso required significantly less time to awakening and to extubating. Therefore, group Iso shortened the length of ICU stays. In conclusion, isoflurane with combined use of low dose fentanyl anesthesia is an acceptable method of anesthesia for open heart surgery.

Effects on liver and serum lipids of dietary supplements of methionine and excess lysine given to previously-starved rats.

The addition of lysine hydrochloride (50 g/kg) to a diet supplemented with methionine (3 g/kg) had no effect on liver lipids when rats (Wistar and Sprague-Dawley) were fed ad lib. for 14 d. However, refeeding a diet supplemented with methionine and excess lysine hydrochloride to previously-starved rats (Wistar) for 6, 7 or 9 d, but not 3 or 4 d, resulted in liver lipid accumulation, mainly triglycerides, which was prevented by the addition of arginine, citrulline, ornithine, adenine, allopurinol or maize oil, but not by guanine, cytosine, thymine or uracil. The addition of lysine hydrochloride to a methionine-supplemented diet resulted in reduced serum triglyceride levels after refeeding for 3 or 4 d and reduced serum cholesterol levels after refeeding for 3, 4 or 6 d. Serum lipids were unaffected by refeeding the diets for 7 or 9 d. Since hepatic lipid accumulation was preceded by the decline in the level of serum triglycerides, one of the factors responsible for lipid accumulation in the liver might be reduced transport of triglycerides from the liver into the blood. When adenine and allopurinol were added to the diet supplemented with methionine and lysine hydrochloride refed for 4 d, there was an increase in serum triglycerides. However, when this diet was refed for 7 d, with the addition of arginine, citrulline, guanine, pyrimidine bases, allopurinol or maize oil, no effects on serum cholesterol and triglyceride levels were observed.