Teruko Sameshima

Identification and Quantitative Determination of Fentanyl Metabolites in Patients by Gas Chromatography-Mass Spectrometry

Although fentanyl has been used widely as a short-acting narcotic analgesic, its metabolism in humans has not been clarified. In this study, three fentanyl metabolites were identified in the urine of eight surgical patients receiving 0.3-0.5 mg of fentanyl intravenously. The metabolites 4-N-(N-propionylanilino)piperidine, 4-N-(N-hydroxypropionylanilino)piperidine and 1-(2-phenethyl)-4-N-(N-hydroxypropionylanilino)piperidine, and unchanged fentanyl were identified by GC-mass spectrometry in urine collected 6 h after administration. Fentanyl and its main metabolite, 4-N-(N-propionylanilino)piperidine, were determined quantitatively in the urine of five additional patients receiving 0.5 mg fentanyl intravenously. Urinary excretion of fentanyl and 4-N-(N-propionylanilino)-piperidine during the first 12 h after injection accounted for 0.3-4.0% and 26 to 55% of the dose, respectively.

The effects of sevoflurane anesthesia on insulin secretion and glucose metabolism in pigs.

We investigated the effects of two different concentrations of sevoflurane, 0.4 minimum alveolar anesthetic concentration (MAC) and 1.0 MAC, on insulin secretion before, during, and after sevoflurane anesthesia using three successive intravenous glucose tolerance tests (IVGTT) in pigs with indwelling catheters. We also investigated changes in the levels of plasma glucose, catecholamines (epinephrine [E], norepinephrine [NE]), and cortisol (Cor). The pigs were grouped as awake, 0.4 MAC, or 1.0 MAC. Sevoflurane decreased the ratio of insulin/glucose (INS/GLU) in the basal condition (P < 0.05 awake versus 1.0 MAC) and during IVGTT (P < 0.01 awake versus 1.0 MAC and 0.4 MAC). These decreases were quickly reversible (control levels were regained within 2 h of the end of anesthesia), were probably dose-related, appeared not to be mediated by E, NE, or Cor. In addition, the INS/GLU ratio 2.5-4 h after the end of anesthesia was significantly higher in the anesthetized groups than in the awake group. We conclude that sevoflurane anesthesia has a rapidly reversible inhibitory effect on basal and glucose-stimulated insulin secretion, as do other inhaled anesthetics, and might induce insulin resistance. (Anesth Analg 1997;84:1359-65)

Comparison between sevoflurane and isoflurane anesthesia in pig hepatic ischemia-reperfusion injury

AbstractPurpose. Sevoflurane and isoflurane have been reported to exert protective effects against ischemia-reperfusion injury (IRI) in various organs. To compare the effect of sevoflurane anesthesia on liver IRI with that of isoflurane anesthesia, we performed the present study in pigs. Methods. Nineteen pigs were assigned to either the sevoflurane (n = 9) or the isoflurane group (n = 10). Hepatic warm ischemia was produced by 30-min hepatic artery and portal vein clamping beginning 90 min after the start of the inhalation anesthesia; this was followed by a 240-min reperfusion. To extend our evaluation, we evaluated the degree of IRI using various parameters (plasma α-glutathione-S-transferase [α-GST], lipid peroxide, and lactate concentrations), in addition to the conventionally used liver damage markers. Results. The lactate level was significantly higher under isoflurane than under sevoflurane at 120 min after reperfusion (4.0 ± 0.4 mmol·l−1vs 2.5 ± 0.3 mmol·l−1; P < 0.05). How-ever, this difference had disappeared after 240 min of reperfusion. No significant differences between the two groups were observed in values for α-GST, lipid peroxides, aspartate aminotransferase, alanine aminotransferase, or lactic dehydrogenase. Conclusion. The extent of the hepatic IRI seen under sevoflurane anesthesia in pigs did not differ significantly from that seen under isoflurane, as judged from measurements of a number of parameters over a 240-min reperfusion period.