Un nuevo anestésico intravenoso: propofol : evaluación clínica y experimental en el perro

El propofol es un anestésico intravenoso no relacionado químicamente con ningún otro anestésico conocido. La inducción anestésica con propofol es rápida y el mantenimiento puede realizarse, bien mediante infusión continua, bien con dosis de mantenimiento en «bolus», y no presenta efecto acumulativo como ocurre con el tiopental sódico, anestésico muy similar en cuanto a acción anestésica y que sirve de referencia. Puede complementarse con analgésicos opiáceos u óxido nitroso para proporcionar analgesia. Al ser la recuperación anestésica más rápida en comparación con otros agentes anestésicos intravenosos o intramusculares, se reduce la aparición de complicaciones.Propofol is a new intravenous anaesthetic agent chemically unrelated to any other anaesthetic. When propofol is used, anaesthetic induction is fast and maintenance can be achieved by continuous infusion or by incremental doses in «bolus», without the cumulative effect seen with thiopentone, a well known barbiturate with similar anaesthetic activity and used as a reference drug. Complementation with opioids or nitrous oxide can provide adequate analgesia. Compared to other intravenous or intramuscular anaesthetic agents, anaesthetic recovery is fast, reducing the complications associated with more prolonged recoveries

Virtual synchronous-machine control of voltage-source converters in a low-voltage microgrid

In order to facilitate the further integration of distributed renewable generation into existing power systems, enhanced control schemes for grid-tied power electronic converters are necessary to ensure non-synchronous power sources can provide power and support to the grid. The virtual-synchronous-machine concept proposes the use of control schemes to enable static generators to operate with the dynamics of rotating synchronous generators. In this paper, a control scheme is presented based on the principle of active-power synchronization to regulate the active power of a grid-tied voltage-source converter based on an emulation of the synchronous-machine swing equation. Design of a cascaded inner-loop voltage and resonant current control is presented to regulate the output voltage as specified via the outer-loop virtual-machine control scheme responsible for power regulation. The performance of this control scheme is investigated within the context of microgrid operation for the provision of active and reactive power to the system, and microgrid frequency support. Experimental validation is provided via the use of a 15 kVA three-phase VSC in a 90 kVA 400V microgrid