Anaesthesiologie und Reanimation
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Anaesthesiol Reanim · Jan 1997
Review Comparative Study[Local anesthetics--maximum recommended doses].
"Maximum doses" determined up to now do not take account of such important pharmacokinetic and toxicological data as: 1) the dependence of blood levels measured on the technique of regional anaesthesia, 2) and the raised toxicity of a local anaesthetic solution containing adrenaline following inadvertent intravascular (intravenous) injection. A maximum dose recommendation differs according to the technique of local anaesthesia for A: subcutaneous injection, B: injection in regions of high absorption, C: single injection (perineural, e.g. plexus), D: protracted injection (catheter, combined techniques), E: injection into vasoactive regions (near to the spinal cord, spinal, epidural, sympathetic). This sequential categorization also underscores the need to select appropriate techniques as well as concomitant monitoring according to the technique of administration and to the expected and possible plasma level curve. ⋯ They must be varied individually depending on the body weight and condition of the patient. Recommended maximum doses are of orientative significance, they do not constitute a maximum dose. There is no quantitative limit for ropivaccine because the recommended techniques do not allow higher volumes of this long acting local anaesthetic.
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Anaesthesiol Reanim · Jan 1997
Review[Ventilation modes and strategies in intensive care medicine].
Advances in ventilator technology and recent findings in pathophysiological mechanisms have resulted in a remarkable decrease in classical volume controlled and pressure controlled ventilation modes as treatment for severe acute respiratory insufficiency. New modes of ventilatory support enabling and encouraging patients' spontaneous breathing, such as Biphasic Positive Airway Pressure (BIPAP) and Airway Pressure Release Ventilation (APRV), make it possible to adapt ventilatory support better and more easily to suit patients' needs than conventional modes of controlled ventilation. Preservation and support of patients' spontaneous breathing improves pulmonary gas exchange and reduces stress imposed by mechanical ventilation. ⋯ Through this, the need for sedation and analgesia is considerably reduced and this may minimize systemic side-effects and complications from analgo-sedation and mechanical ventilation. The drugs should be administered in an adequate, individually adapted manner. Routinely-ordered and fixed combinations of drugs administered continuously are not adequate adequate as they further carry the risk of overdosing a different single drug with the corresponding side-effects (depression of respiratory drive, gut motility, etc.).
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Anaesthesiol Reanim · Jan 1997
Review Comparative Study[Critical evaluation of the new inhalational anesthetics desflurane and sevoflurane].
New anaesthetic agents are being continuously developed to find the ideal agent. The most commonly used inhaled anaesthetic in adults is isoflurane and in children halothane. The need for, and the value of the new agents desflurane and sevoflurane depend on a comparison of the properties of a theoretically ideal agent with those of isoflurane, halothane and the new agents. ⋯ Desflurane has a major advantage over sevoflurane: it is not biotransformed nor does it interact with carbon dioxide absorbents. However, desflurane is associated with troublesome cardiovascular stimulation involving tachycardia and both pulmonary and systemic hypertension. Sevoflurane appears to be advantageous for three reasons: firstly, because of its pleasant odour and consequent suitability for induction by inhalation, particularly in paediatric anaesthesia; secondly, it can be used with currently employed vaporizers, and thirdly, surgical demands can be met by lower doses, because its potency is higher.
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Anaesthesiol Reanim · Jan 1997
Review[Pharmacokinetics from the viewpoint of the clinical anesthetist].
Pharmacokinetics describes the time-depend course of plasma concentration of a drug. Pharmacodynamics describes the pharmacological effect of the substance. Both together form the pharmacological model used in clinical practice. ⋯ The main clinical use of pharmacokinetics is to sustain dosing schemes based on scientific data. It also may be helpful in creating new administration schemes especially for continuous infusion of intravenous hypnotics or analgetics. New developments such as Target-Controlled Infusion (TCI) are based on pharmacokinetic data and computations and may be an improvement for the clinically working anaesthetist.
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Anaesthesiol Reanim · Jan 1997
Review[Artificial humidification of inspired gas--status of knowledge and technique].
Artificial humidification of inspired air serves to maintain or restore physiological heat and moisture conditions in the bronchial system in intubated or tracheotomized patients. The need to condition the respiratory gases in these patients is undisputed. The present paper reviews the pathophysiology and methods of the artificial active and passive humidifying of inspired gases. ⋯ Present-day medical knowledge indicates that passive artificial humidifying of respiratory gases (heat and moisture exchanger, HME) is adequate to meet most requirements for warming and moistening the inspiratory air in patients whose upper airways are devoid of natural conditioning of respiratory gases in consequence of intubation and tracheotomy. This applies to artificial ventilation in prehospital situations, artificial ventilation in anaesthesia and long-term artificial ventilation on the intensive care unit. With appropriate restrictions, the respiratory air of patients who breathe spontaneously via an artificial air vent (e.g. tracheal cannula) can also be conditioned by HME.