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Electroconvulsive therapy is a well-established form of treatment for a broad spectrum of severe psychiatric disorders. The treatment, in which a generalized epileptic seizure is provoked by electrical stimulation of the brain, is performed with the patient under anesthesia and muscle relaxation. Therefore, sufficient knowledge of the physiological and pharmacological characteristics is an essential requirement for safe anesthesia. The following review is intended to provide some new aspects of the procedure and management of anesthesia. [ABSTRACT FROM AUTHOR]

Abstract: Super-homogenisation (SPH) factors were generated by a modified version of the code DYN3D for PWR fuel assemblies in hot-zero-power states defined in the OECD MOX/UO2 Benchmark. SPH factors averaged for each pin-material type and factors for each individual pin position were produced. The application of the SPH factors improves the accuracy of DYN3D calculations, especially for configurations with control rods inserted. [Copyright &y& Elsevier]

Abstract: The core model DYN3D which has been developed for three-dimensional analyses of steady states and transients in thermal reactors with quadratic or hexagonal fuel assemblies is based on nodal methods for the solution of the two-group neutron diffusion equation. Loading cores with higher content of MOX fuel, the increase of the fuel cycle length, and the consideration of new reactor types are challenging for these standard methods. A nodal expansion method for solving the equations of the simplified P 3 (SP3) approximation of the multigroup transport equation was developed to improve the accuracy of the DYN3D code. The method described in the paper is verified with pinwise calculations of a steady state of the OECD/NEA and US NRC PWR MOX/UO2 Core Transient Benchmark. The used 16-group cross section library was generated for DORT calculations with homogenized pin cells. Two different approximations of the diffusion coefficient which occurs in the within-group form of the SP3 equations are investigated. Using the transport cross section for the calculation of the diffusion coefficient gives much better results than those obtained with the removal cross section. The improvement of the results in comparison to a pinwise diffusion calculation is shown. The results are compared with the DORT and the heterogeneous reference solution of the code DeCART. Concerning the SP3 calculation using the diffusion coefficient based on the transport cross section (DYN3D-SP3-TR) the deviations of the eigenvalue k eff and the assembly powers from the transport solutions of DORT and DeCART are in the same order as those between the two transport solutions themselves. The improvement of the DYN3D-SP3-TR results in comparison to the diffusion calculation is presented. As the DYN3D-SP3-TR and DORT calculations are performed with homogenized pin cells, the pin powers of the two calculations are closer to each other than to the pin powers of the DeCART solution. To estimate the contribution of higher flux-moments, the ratio of the second flux moment to the zeroth flux moment is investigated along a horizontal row of pins. It is shown that it is low in the fuel assemblies with small peaks at the water channels. Considering the baffle and the water reflector regions higher values are obtained in the fast neutron groups. [Copyright &y& Elsevier]

Abstract: Measurements carried out in an original-size VVER-1000 mock-up (V-1000 facility, Kurchatov Institute, Moscow) were used for the validation of three-dimensional neutron-kinetic codes, designed for VVER safety calculations. The significant neutron flux tilt measured in the V-1000 core, which is caused only by radial-reflector asymmetries, was successfully modeled. A good agreement between calculated and measured steady-state powers has been achieved, for relative assembly powers and inner-assembly pin power distributions. Calculated effective multiplication factors exceed unity in all cases. The time behaviour of local powers, measured during two transients that were initiated by control rod moving in a slightly super-critical core, has been well simulated by the neutron-kinetic codes. [Copyright &y& Elsevier]

Background: Cardiopulmonary bypass (CPB) induces a systemic inflammatory reaction. Microcirculation-dependent alteration of the gut mucosal barrier with subsequent translocation of endotoxins is a postulated mechanism for this inflammatory response. This study was designed to elucidate whether two different approaches to modulate splanchnic perfusion may influence systemic inflammation to CPB.Methods: We examined 40 patients scheduled for elective coronary bypass surgery in a prospective, randomized study. One group (DPX) received dopexamine (1 micro g. kg-1. min-1) continuously after induction of anesthesia until 18 h after CPB. The control group (CON) received equal volumes of NaCl 0.9% in a time-matched fashion. In a third group (EPI) a continuous epidural infusion of bupivacaine 0.25% [(body height (cm) - 100). 10-1=ml.h-1] was administered for the whole study period. Procalcitonin (PCT), tumor necrosis factor (TNF-alpha), soluble TNF receptor, human soluble intercellular adhesion molecule-1, C-reactive protein (CRP) and leukocyte count were measured as parameters of inflammation.Results: All parameters significantly increased following CPB. Increases of PCT, TNF-alpha and leukocyte count were significantly attenuated in the DPX and EPI groups at different time points. However, neither splanchnic blood flow nor oxygen delivery and consumption were different when compared with the CON-group.Conclusion: These results do suggest that mechanisms other than an improved splanchnic blood flow by DPX and EPI treatment have to be considered for the anti-inflammatory effects. [ABSTRACT FROM AUTHOR]

Background: Nitrous oxide (N2O) has been suggested to contribute to bowel distension, resulting in worsened operating conditions for laparoscopic surgery, and to increase incidence of postoperative nausea and vomiting. Therefore, our objective was to assess the feasibility of two remifentanil-based anaesthetic regimens free from N2O with special regard to recovery profile, postoperative analgesic demand and side effects in patients undergoing laparoscopic cholecystectomy.Methods: Fifty patients (ASA I-II, 23-65 yr) were randomly assigned to receive remifentanil-based anaesthesia in conjunction with propofol (group R/P) or desflurane (group R/D). After standardised induction of anaesthesia, analgesia was continued with remifentanil in all patients. For maintenance of hypnosis, propofol or desflurane were used in concentrations to ensure loss of consciousness, lack of awareness, and maintenance of heart rate and blood pressure within +/- 25% of initial values. At the end of surgery all anaesthetics were discontinued without tapering and early emergence and recovery were recorded. Pain scores were assessed by using a visual analogue scale. Patient-controlled analgesia with i.v. piritramide was used for treatment of postoperative pain and recorded for 90 min in the postanaesthesia care unit (PACU). In addition, side effects were noted.Results: Early emergence from anaesthesia did not differ between the groups. In group R/P, time to eye opening, spontaneous respiration and extubation was 4.4 +/- 2.9 min, 5.2 +/- 3.4 min and 5.5 +/- 3.3 min respectively, compared with 4.7 +/- 2.7 min, 5.3 +/- 2.4 min and 5.7 +/- 2.5 min in group R/D. While pain scores did not differ between both groups on admission to the PACU, patients receiving desflurane required more i.v. piritramide as compared to those receiving propofol, 22.0 +/- 6.5 mg and 17.9 +/- 7.0 mg, respectively (P<0.05). Nausea was less frequent after propofol (16% vs. 48%, P<0.05).Conclusion: In patients undergoing laparoscopic cholecystectomy, remifentanil-based anaesthetic regimens in conjunction with propofol or desflurane are suitable and allow for rapid recovery from anaesthesia. However, the use of propofol results in less postoperative analgesic consumption and nausea as compared to desflurane. [ABSTRACT FROM AUTHOR]

Objective: To compare the onset properties of 0.3 mg/kg rocuronium during co-induction of anaesthesia with desflurane, isoflurane or total intravenous anaesthesia (TIVA) with propofol/remifentanil. Design: A prospective, randomised controlled trial carried out in surgical patients. Patients: 60 adult ASA I-II patients undergoing general anaesthesia for elective surgery were randomised to three groups (n = 20 each) according to the anaesthetic technique: co-induction with desflurane, isoflurane or TIVA. Methods: Neuromuscular transmission was assessed by electromyography (EMG) with Train-of-Four stimulation. In all patients anaesthesia was induced and maintained during the whole study with propofol 2.0 to 2.5 mg/kg intravenously followed by a continuous infusion (4 to 6 mg/kg/h) and 0.25 µg/kg/min remifentanil. After stabilisation of the EMG-response patients received 0.3 mg/kg rocuronium concomitantly with desflurane or isoflurane, both at an inspired concentration of 1 MAC (minimum alveolar concentration), or no volatile anaesthetic (TIVA control-group). Maximum neuromuscular block and onset time of rocuronium-induced neuromuscular blockade were measured. Results: The maximum neuromuscular block after rocuronium 0.3 mg/kg was significantly deeper in the desflurane group compared with isoflurane or TIVA [96% (range 79-100) vs 87% (range 69-97) and 86% (range 65 - 100), respectively; p < 0.01]. Onset time did not differ between the three groups [242s (range 160-380), 252s (range 160-400), and 244s (120-400), respectively; not significant]. Conclusions: Co-induction with desflurane led to a deeper rocuronium-induced neuromuscular block compared with isoflurane or TIVA. Faster uptake and distribution of desflurane may be the main reasons for this early interaction between desflurane and rocuronium. [ABSTRACT FROM AUTHOR]

Abstract: Plant-measured data provided by the OECD/NEA VVER-1000 coolant transient benchmark programme were used to validate the DYN3D/RELAP5 and DYN3D/ATHLET coupled code systems. Phase 1 of the benchmark (V1000CT-1) refers to an experiment that was conducted during the commissioning of the Kozloduy NPP Unit 6 in Bulgaria. In this experiment, the fourth main coolant pump was switched on whilst the remaining three were running normal operating conditions. The experiment was conducted at 27.5% of the nominal level of the reactor power. The transient is characterized by a rapid increase in the primary coolant flow through the core, and as a consequence, a decrease of the space-dependent core inlet temperature. The control rods were kept in their original positions during the entire transient. The coupled simulations performed on both DYN3D/RELAP5 and DYN3D/ATHLET were based on the same reactor model, including identical main coolant pump characteristics, boundary conditions, benchmark-specified nuclear data library and nearly identical nodalization schemes. In addition to validation of the coupled code systems against measured data, a code-to-code comparison between simulation results has also been performed to evaluate the respective thermal hydraulic models of the system codes RELAP5 and ATHLET. [Copyright &y& Elsevier]

On the basis of methods developed recently for square-fuel-assembly reactor cores, discontinuity factors for hexagonal VVER (Russian PWR) control absorbers and reflector nodes have been derived. Partial currents from heterogeneous multi-group transport calculations are used for the determination of the discontinuity factors. As shown by suitable benchmark calculations, the application of these quantities in the two-group nodal diffusion code DYN3D clearly improves the results of assembly-power predictions. The advantage of reflector diffusion parameters, including discontinuity factors, over conventional albedos has been demonstrated. [Copyright &y& Elsevier]

There is an ongoing debate as to whether propofol exhibits pro- or anticonvulsant effects, and whether it should be used in patients with epilepsy. We prospectively assessed the occurrence of seizure-like phenomena and the effects of intravenous propofol on the electroencephalogram (EEG) in 25 children with epilepsy (mean (SD) age: 101 (49) months) and 25 children with learning difficulties (mean (SD) age: 52 (40) months) undergoing elective sedation for MRI studies of the brain. No child demonstrated seizure-like phenomena of epileptic origin during and after propofol sedation. Immediately after stopping propofol, characteristic EEG changes in the epilepsy group consisted of increased beta wave activity (23/25 children), and suppression of pre-existing theta rhythms (11/16 children). In addition, 16 of 18 children with epilepsy and documented EEG seizure activity demonstrated suppression of spike-wave patterns after propofol sedation. In all 25 children with learning difficulties an increase in beta wave activity was seen. Suppression of theta rhythms occurred in 11 of 12 children at the end of the MRI study. In no child of either group was a primary occurrence or an increase in spike-wave patterns seen following propofol administration. The occurrence of beta wave activity (children with learning difficulties and epilepsy group) and suppression of spike-wave patterns (epilepsy group) were transient, and disappeared after 4 h. This study demonstrates characteristic, time-dependent EEG patterns induced by propofol in children with epilepsy and learning difficulties. Our data support the concept of propofol being a sedative-hypnotic agent with anticonvulsant properties as shown by depression of spike-wave patterns in children with epilepsy and by the absence of seizure-like phenomena of epileptic origin. [ABSTRACT FROM AUTHOR]