Intraoperative high-dose remifentanil increases post-anaesthetic shivering.

BACKGROUND: Remifentanil is associated with increased incidence of post-anaesthetic shivering (PAS). The aim of this study was to compare the effects of intraoperative high and low doses of remifentanil on PAS. METHODS: We investigated 50 consecutive patients, aged <60 yr, who underwent gynaecological laparotomy. Patients who underwent prolonged surgery (>4 h) were excluded from the study. Anaesthesia throughout surgery was maintained with i.v. propofol and remifentanil, and epidural ropivacaine, and no nitrous oxide was used. Fifty patients were randomly assigned to receive intraoperative remifentanil at 0.1 microg kg(-1) min(-1) (low-dose group, n=25) or 0.25 microg kg(-1) min(-1) (high-dose group, n=25) until the end of surgery. Intraoperative analgesia was achieved by a fixed infusion rate of remifentanil and titrated epidural ropivacaine. PAS was evaluated by nursing stuff over the first hour after surgery. RESULTS: PAS occurred more frequently in the high-dose group than in the low-dose group (60% vs 20%, P=0.009). None of the patients complained of pain during the observation period due to epidural analgesia. There were no significant differences in rectal or palm skin temperature after extubation between the two dose groups. CONCLUSIONS: Remifentanil-induced PAS is not a phenomenon of intraoperative hypothermia. The higher incidence of PAS with higher doses of remifentanil probably reflects acute opioid tolerance and stimulation of N-methyl-d-aspartate receptors, similar to hyperalgesia. We conclude that patients administered high doses of remifentanil are sensitive to shivering after sudden drug withdrawal.

Analysis of postrevascularization syndrome after orthotopic liver transplantation: the experience of an Australian liver transplantation center.

BACKGROUND/PURPOSE: We investigated the causes and examined patient outcomes following the postrevascularization syndrome (PRS) during orthotopic liver transplantation (OLTx). METHODS: PRS was defined as a fall in the mean arterial pressure at 5 min after revascularization to less than 70% of the baseline and lasting for 5 min. Data from 100 adult patients who underwent OLTx between January 1998 and September 2000 were analyzed. Analyzed data included donor and recipient demographic data, recipient operative and postoperative courses, and recipient outcome. RESULTS: Twenty-nine patients (29%) exhibited PRS during OLTx (PRS group). There was a higher incidence of older donors (>50 years) in the PRS group (48% vs 23%; P < 0.05). Postrevascularization hyperkalemia and metabolic acidosis were observed in both the PRS and non-PRS groups. Transaminase and lactate levels after revascularization were significantly higher in the PRS group ( P < 0.05). Alkaline phosphatase and gamma-glutamyl transpeptidase levels on day 7 tended to be higher in the PRS group; although the difference was not significant (p > or = 0.05). Serum creatinine was significantly elevated on day 7 in the PRS group ( P < 0.01). CONCLUSIONS: Our results indicate that PRS following OLTx tended to be more common in liver allografts from older donors and was associated with posttransplantation liver and renal dysfunction.

Gas Sensing Based on a Nonlinear Response: Discrimination between Hydrocarbons and Quantification of Individual Components in a Gas Mixture.

A novel sensing system is proposed based on the multidimensional information contained in a dynamic nonlinear response. A sinusoidal temperature change was applied to a SnO(2) semiconductor gas sensor, and the resulting output conductance of the sensor was analyzed by fast Fourier transformation (FFT). The higher harmonics of the FFT characterized the nonlinear properties of the response. The amplitudes of the higher harmonics of the FFT exhibit characteristic changes which depend on the chemical structure, concentration, and the kinetics of adsorption and the reaction of hydrocarbon gases and aromatic vapors on the sensor surface. In addition, it is possible to distinguish between gases in a gaseous mixture with a single detector using this dynamic nonlinear response. Nonlinear responses are discussed in relation to the kinetics of the reaction at the sensor surface and the temperature-dependent barrier potential of the semiconductor.

Induction of the fundic mucosa-specific glycolipid with dimethylformamide in gastric-cancer cell lines.

We have previously reported that a glycolipid GalNAc beta 1-4[NeuAc alpha 2-3]Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc-Cer named NGM-1 is present specifically in the human gastric fundic mucosa, but not in other organs. In gastric-cancer tissue and cancer cell lines, this glycolipid completely disappears. These findings imply that NGM-1 is expressed only in well-differentiated fundic mucosa. The purpose of this study is to examine the expression of NGM-1 as a differentiation-related molecule. A gastric cell line AZ521 was cultured in the medium with various reagents which had been reported to induce differentiation in cancer cells. The growth of AZ521 was suppressed by the addition of 0.8% dimethylformamide (DMF) to the medium, but not by addition of dimethylsulfoxide (DMSO), retinoic acid or butyric acid. In the ganglioside fraction of the cells cultured with DMF, a glycolipid regarded as NGM-1 which had not been present before treatment was detected using a monoclonal antibody. Suppression of the proliferation of AZ521 by eliminating the serum from the medium could not induce the expression of NGM-1. A colonic cell line treated with DMF also failed to express the glycolipid. The synthase activity of NGM-1 was elevated in the AZ521 cells treated with DMF, but not with DMSO. These results demonstrate that the expression of NGM-1 is induced by DMF specifically in gastric-cancer cells, and suggest the possibility that NGM-1 is a differentiation-related molecule.