Der Anaesthesist
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Randomized Controlled Trial Clinical Trial Controlled Clinical Trial
[Low-flow anesthesia with desflurane].
Due to its low solubility and negligible metabolism, desflurane is assumed to be especially suitable for application by low-flow anaesthetic techniques. The aim of this clinical investigation was the development of a standardised dosing scheme for low-flow and minimal-flow desflurane anaesthesia. ⋯ The pharmacokinetic properties of desflurane, resulting in especially low individual uptake, and the wide output range of the vaporizer facilitate the use of low-flow anesthetic techniques in routine clinical practice. Even in minimal-flow anesthesia, the duration of the initial high-flow phase can be shortened to min. If the flow is reduced to 1 l/min, the inspired desflurane concentration achieved in the initial high-flow phase can be maintained without any alteration of the vaporizer setting. In minimal-flow anesthesia, however, with flow reduction to 0.5 l/min, the fresh gas concentration has to be increased to a value 1%-2% higher than the inspired nominal value. Due to the wide dialing range of the desflurane vaporizer, the amount of vapour delivered into the breathing system can be increased to about 110 ml/min even at a flow of 0.5 l/min. The large amount of agent that can be delivered into the system even under low-flow conditions, together with the very low individual uptake, results in a time-constant that is sufficient short for the clinically required rapid increase in inspired desflurane concentrations. The short time-constant of low-flow desflurane anaesthesia improves the control of the anaesthetic concentration. If all measures are taken to safely avoid inadvertent drying out of the soda lime, there is no evidence that low-flow anaesthesia with desflurane is liable to increase the risk of accidental carbon monoxide poisoning. (ABSTRACT TRUNCATED)
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Thirty years ago, cardiopulmonary resuscitation (CPR) was primarily developed for otherwise healthy individuals who experienced sudden cardiac arrest. Today, CPR is widely viewed as an emergency procedure that can be attempted on any person who undergoes a cessation of cardiorespiratory function. Therefore, the appropriateness of CPR has been questioned as a matter of the outcome, the patient's preferences, and the cost. The objective of this article is to analyse ethical issues in prehospital resuscitation. ⋯ The standard of care remains the prompt initiation of CPR. However, ethical principles such as beneficence, nonmaleficence, autonomy, and justice have to be applied in the unique setting of emergency medicine. Physicians have to consider the therapeutic efficacy of CPR, the potential risks, and the patient's preferences.
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Patients have the right to make decisions concerning their health care. The right to consent to or refuse treatment is based on the ethical principle of autonomy. Respecting a patient's autonomy has emerged as one of the leading principle in medical ethics in the last years. ⋯ I believe that defining accepted and refused interventions in advance is not an appropriate approach to DNR orders during anaesthesia and surgery, as it will be difficult to find a definition of what constitutes resuscitation in this context. Communication with the patient and exchange of information are essential factors promoting ethical decisions. Knowing the individual patient's preferences and fears, a more suitable approach seems to be the perioperative suspension of the DNR order for a limited period of time, with the assurance that therapeutic procedures instituted during surgery will be discontinued postoperatively in reconsideration of the DNR order and if the underlying disease process turns out to be non-reversible.