Der Anaesthesist
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It is a strange contradiction that increasingly sophisticated anaesthesia machines are developed meeting all requirements for rebreathing techniques and the highest safety standards, but the usual anaesthetic management is still based on the use of fresh gas flows that preclude substantial rebreathing. The advantages of rebreathing can only be realised if low-flow anesthesia techniques are adopted. Increasing acceptance of these methods is due to the availability of comprehensive anaesthetic gas monitoring. ⋯ The use of new inhalational anaesthetics such as desflurane that require comparatively high concentrations, or even xenon, will motivate to sparing use. Increasingly stringent health and safety regulations as well as sharpened ecological awareness will prompt anaesthetists to minimise all anaesthetic gas emission according to the possibilities of available equipment. Last but not least, the demand for economical working methods will be an argument for applying low-flow anaesthesia techniques.
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Review Comparative Study
[Sufentanil. An alternative to fentanyl/alfentanil?].
The introduction of the new opioid, sufentanil, into clinical practice should focus on the following questions: (1) What are the pharmacokinetic features of sufentanil that make it different from the well-established congeners alfentanil and fentanyl and open the way to new perspectives? and (2) Does sufentanil offer any particular advantages for specialised surgical procedures that make it the drug of first choice? Pharmacokinetics. Sufentanil is a potent analgesic with a very high receptor affinity and specificity, high lipid solubility, marked protein binding, and a shorter elimination half-life than fentanyl. Due to the high hepatic extraction ratio, metabolic degradation and elimination depend more on hepatic perfusion than on enzyme activity or renal clearance. ⋯ Epidural application of 10-50 micrograms sufentanil provides rapid and effective pain relief within 5-7 min for a period of 3-7 h. Doses of more than 50 micrograms seem to increase the risk of respiratory depression without further improvement of analgesia. Analgesia may be enhanced by combination with local anaesthetics or clonidine.(ABSTRACT TRUNCATED AT 400 WORDS)
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The laryngeal mask (LM) was developed by A. Brain to overcome the disadvantages of the face mask (impractical) and the tracheal tube (invasive). Today this new instrument is applied on a broad scale in Great Britain and with growing interest in continental Europe. ⋯ Apart from anaesthesia, the LM can be used for bronchoscopy in children, for difficult intubations and as a preliminary airway in cases of resuscitation. Two studies performed in Great Britain have evaluated the LM for resuscitation. The investigations should be confirmed in German-speaking countries.
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It is the purpose of this review to outline the principles of biometric methods in clinical research. Several study designs such as cohort studies, case-control studies or randomized controlled trials are explained in detail, and their problems and their interpretation are discussed. It is demonstrated that observational studies may yield valuable information about associations between exposure and outcome variables but that only properly designed randomized clinical trials of adequate sample size make it possible to answer research questions about causal relationships. It is emphasized that good clinical research depends on properly designed studies more than on complicated statistical procedures.