Annales françaises d'anesthèsie et de rèanimation
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During regional anaesthesia, sedation can be used to obviate any discomfort which is unrelated to a technical insufficiency of the block or a particular anxiety of the patient. Sedation increases the acceptability of the technique by the patient. The main characteristics of propofol are its short onset time of action, and the rapid reversibility of its effects after the end of its administration. ⋯ Maintenance is best achieved with a continuous infusion, at a rate of 3 to 4 mg.kg-1.h-1. Titration of propofol allows the ideal stage of sedation to be reached (MacKenzie Grade 3), followed by a fast recovery. Close monitoring of the patient is mandatory and should include clinical supervision and pulse oximetry in all cases.
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Ann Fr Anesth Reanim · Jan 1994
[Pollution and retro-pollution by the distribution system of medical gases].
The anaesthetic machine, the recovery room or the ICU ventilator as well as any other simple oxygenation device can be accidentally supplied with a "wrong" gas, or a mixture of "wrong" and "true" gases, or a gas containing chemical impurities, as a result of one of the following causes: a) the source of the medical gas pipeline supply contains a "wrong" gas or impurities; b) the gas pipeline is polluted by a "wrong" gas or solvents, introduced during the installation or maintenance of the pipeline; c) the pipeline is polluted by a wrong gas at a point of inter-connection or cross-connection of two pipelines; d) supply of a "wrong" gas through wrong quick couplers connected to the pipeline; e) back flow of a gas in another pipeline supply through a defective gas mixer, which is today the most common cause of pipeline contamination or retropollution. It occurs with some types of mixers in case of absence or malfunction of non-return valves, associated with a pressure difference between the two gas lines. The means of prevention, recognition and emergency treatment of these events include: a) systematic removal of mixers and flowmeter-mixers from supplies when not in use; b) periodical checking of these devices for an accidental communication between the gases to be mixed; c) systematic use of an oxygen analyser for a continuous measurement of FIO2, especially when the machine is connected to the N2O pipeline supply; d) the presence of a reserve cylinder of oxygen connected to every anaesthetic machine.
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Ann Fr Anesth Reanim · Jan 1994
[Arguments for the addition of an oxygen reserve container to the anesthetic equipment].
In France, the presence of an emergency oxygen cylinder as part of every the anaesthetic machine is not made compulsory by an official regulation. This article provides arguments in favour of such a presence, as recommended by the French Society of Anaesthesia and Intensive care (SFAR).
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Ann Fr Anesth Reanim · Jan 1994
[Dysfunction of vaporizers and nitrous oxide: solubility or viscosity?].
Sudden switch of carrier gas from O2 to the N2O/O2 mixture results in an acute decrease in vapour output for a variable delay of time. This has been attributed to the dissolution of N2O in the volatile anaesthetic liquid. The final vapour concentration at steady state had been previously reported to be lower than the concentration dial setting: this was attributed to vaporizer design and to viscosity of carrier gas. ⋯ To test the solubility hypothesis, the same enflurane Dräger Vapor 19 vaporizer was emptied, dried, saturated with enflurane, emptied and then filled with either 10 or 100 mL of liquid enflurane. To test the viscosity hypothesis, a model of a vaporizer was devised, in which the gas movements are described with the Poiseuille's law. In this model, the delivered concentration F depends on the vapour pressure, the input pressure of the gas flow, the viscosity of the carrier gas and the viscosity of the agent saturated gas.(ABSTRACT TRUNCATED AT 250 WORDS)
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The laryngeal mask ensures a better control of the airway than the face mask, without the disadvantages of an endotracheal tube. Moreover, it provides an effective and simple solution to many problems of difficult intubation and therefore it has a place amongst the equipment required for difficult intubations. The laryngeal mask will most probably become more widely used, provided that its contra-indications are taken into account. ⋯ Many studies have shown that propofol is suitable for use with the laryngeal mask. However, it should be noted, that there is, as yet, no conclusive evidence of the superiority of propofol over other induction agents. In anaesthesia for day-case surgery, the combination of the laryngeal mask and propofol could prove beneficial.