Der Anaesthesist
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Evaluation of the patient's medical history and a physical examination are the cornerstones of risk assessment prior to elective surgery and may help to optimize the patient's preoperative medical condition and to guide perioperative management. Whether the performance of additional technical tests (e.g. blood chemistry, ECG, spirometry, chest-x-ray) can contribute to a reduction of perioperative risk is often not very well known or controversial. Similarly, there is considerable uncertainty among anesthesiologists, internists and surgeons with respect to the perioperative management of the patient's long-term medication. ⋯ These recommendations aim to ensure that surgical patients undergo a rational preoperative assessment and at the same time to avoid unnecessary, costly and potentially dangerous testing. The joint recommendations reflect the current state-of-the-art knowledge as well as expert opinions because scientific-based evidence is not always available. These recommendations will be subject to regular re-evaluation and updating when new validated evidence becomes available.
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Randomized Controlled Trial
Spontaneously breathing anesthetized patients with a laryngeal mask airway: positive end-expiratory pressure does not improve oxygen saturation.
Spontaneous ventilation is a popular mode of ventilation for patients with the laryngeal mask airway (LMA). Studies have shown, however, that spontaneous ventilation impairs gas exchange and that assisting or controlling ventilation results in higher oxygen saturation. Atelectasis during general anesthesia is a well described mechanism which impacts on gas exchange. ⋯ The application of a PEEP of +7 cm H₂O with a LMA under spontaneous ventilation cannot be recommended. Limitations of our study were the selection of healthy patients and omitting pre-oxygenation before induction which might have limited the development of atelectasis. In addition arterial partial pressure of oxygen (p(a)O₂) measurements could have revealed subtle changes in oxygenation.
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Opioids are the most potent drugs for treatment of acute and chronic pain. However, accumulating evidence suggests that opioids may paradoxically also enhance pain, often referred to as opioid-induced hyperalgesia. Opioid-induced hyperalgesia is defined as an increased sensitivity to pain or a decreased pain threshold in response to opioid therapy. ⋯ However, it remains unclear whether opioid-induced hyperalgesia develops during continuous chronic application of opioids or on their withdrawal. This review provides a comprehensive summary of clinical research concerning opioid-induced hyperalgesia and the molecular mechanisms of opioid withdrawal and opioid tolerance and other potential mechanisms which might induce hyperalgesia during opioid therapy will be discussed. The status quo of our knowledge will be summarized and the clinical relevance of opioid-induced hyperalgesia will be discussed.
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The new anaesthetic conserving device (ACD) allows the use of isoflurane and sevoflurane without classical anaesthesia workstations. Volatile anaesthetic exhaled by the patient is absorbed by a reflector and released to the patient during the next inspiration. Liquid anaesthetic is delivered via a syringe pump. ⋯ Inhalational sedation with isoflurane has been widely used for more than 20 years in many countries and even for periods of up to several weeks. In the German S3 guidelines for the management of analgesia, sedation and delirium in intensive care (Martin et al. 2010), inhalational sedation is mentioned as an alternative sedation method for patients ventilated via an endotracheal tube or a tracheal cannula. Nevertheless, isoflurane is not officially licensed for ICU sedation and its use is under the responsibility of the prescribing physician.
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The use of extracorporeal membrane oxygenation (ECMO) was established in Germany 25 years ago in specialized centers as an approach for patients suffering from severe life-threatening lung failure. Apart from such indications the inclusion of ECMO as a planned intervention for safety purposes in the postoperative weaning from mechanical ventilation in a 22-year-old woman is described. ⋯ After elective use of veno-venous ECMO the young patient was extubated without risk and lung function was stabilized safely. Extracorporeal lung assist can be indicated apart from rescue management in elective situations for prevention of an airway catastrophe after careful calculation of the harm/benefit ratio.