Journal of anesthesia
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Journal of anesthesia · Mar 1994
Subanesthetic sevoflurane does not affect sympathetic or parasympathetic function.
To evaluate the effects of subanesthetic enflurane and sevoflurane on the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS), the blood level of norepinephrine (NE) and fluctuations in the R-R intervals were measured on electrocardiogram in humans given either 0.5 MAC enflurane or sevoflurane. Enflurane suppressed circulating plasma NE and elevated coefficients of variation (CV) of R-R intervals after 20 and 30 min of inhalation. ⋯ Sevoflurane lowered the CV to 84% of control after 30 min of inhalation. These results indicate that subanesthetic concentrations of sevoflurane are unlikely to perturb sympathetic and parasympathetic activities in humans without surgical stimulation when compared with enflurane.
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Journal of anesthesia · Mar 1994
Sevoflurane reduced but isoflurane maintained hepatic blood flow during anesthesia in man.
The indocyanine green (ICG) clearance rate (K) and estimated total hepatic blood flow (THBF) were studied by the single injection technique. The THBF was estimated from the calculated circulating blood volume and the fixed extraction rate. The blood concentration of ICG was determined by the finger piece technique. ⋯ ICG (0.5 mg·kg-1) was administered intravenously and K was determined three times following the injection. The K value in the halothane and sevoflurane groups decreased significantly 1 h after induction of anesthesia: from 0.188±0.048 to 0.142±0.029 in the halothane group and from 0.178±0.027 to 0.155±0.021 in the sevoflurane group. There was no significant change in the K value in the isoflurane group throughout the study.
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Journal of anesthesia · Mar 1994
Local cerebral blood flow measured by stable xenon CT during fentanyl-diazepam anesthesia.
We assessed the local cerebral blood flow (LCBF) in 40 patients under fentanyl-diazepam anesthesia. The measurement of LCBF was made using 50%-70% stable xenon with 20 min of inhalation interval and a shuttle method for computed tomography imaging. All patients were anesthetized with 5.95±1.76 μg·kg-1 fentanyl and 0.22±0.07 mg·kg-1 diazepam under mechanical ventilation during CBF measurement. ⋯ The cerebral carbon dioxide reactivity, expressed as percentage change in LCBF per unit change in arterial carbon dioxide partial pressure, was 5.39±1.07, and there were no significant differences of reactivity among regions studied. In conclusion, we showed reference values of LCBF and carbon dioxide reactivity, measured by stable xenon-enhanced computed tomography, in patients under fentanyl-diazepam anesthesia. Carbon dioxide reactivity was preserved in all regions including gray matter, white matter, and basal ganglia.