Current opinion in anaesthesiology
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Surgical trauma and anaesthetics may cause immune suppression, predisposing patients to postoperative infections. Furthermore, stress such as surgery and pain per se is associated with immune suppression which, in animal models, leads to an increased susceptibility to infection and tumour spread. Thus, by modulating the neurohumoral stress response, anaesthesia may indirectly affect the immune system of surgical patients. ⋯ There is a striking body of evidence that long-term exposure to certain sedatives is paralleled by infectious complications. On the other hand, anti-inflammatory effects of anaesthetics may be therapeutically beneficial in distinct situations such as those involving ischaemia/reperfusion injury or the systemic inflammatory response syndrome. Consequently, sedatives should be administered with careful regard to their respective potential immunomodulatory properties, the clinical situation, and the immunity status of the critically ill patient.
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Recently, there has been considerable interest in regional anaesthetic techniques, particularly in peripheral nerve blockade, for orthopaedic limb surgery. Many traditional nerve-block techniques have been significantly modified to improve their role in both in-patient and out-patient surgery. The introduction of long-acting local anaesthetic with a better safety profile as well as better equipment for continuous nerve blockade has further increased the use of such techniques in the provision of postoperative analgesia. The recent developments described in this review are likely to result in wider use of these techniques in years to come.
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Clonidine is a partial alpha 2 adrenergic agonist that has a variety of different actions including antihypertensive effects as well as the ability to potentiate the effects of local anesthetics. It can provide pain relief by an opioid-independent mechanism. It has been shown to result in the prolongation of the sensory blockade and a reduction in the amount or concentration of local anesthetic required to produce perioperative analgesia. ⋯ In another study, the effects of clonidine used for intra-articular administration in combination with morphine were investigated. These authors found a significantly higher rate of satisfaction in the group of patients receiving clonidine plus morphine. Although several recent studies have shown certain benefits from the use of clonidine for regional anesthesia, further investigations are necessary to clarify its role.
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The cancer patient presents special challenges to the anesthesiologist. Cancer may have multiple effects including those due to the primary tumor, metastases, the effects and toxicity of cancer therapy, associated paraneoplastic and physiologic responses to the tumor and the strong psychological responses elicited by cancer. ⋯ Patient education and reassurance regarding issues of safety, pain control and respect for patient preferences are important goals as well. This review provides the anesthesiologist with both general and specific information important to the systematic and complete preoperative evaluation of the patient with cancer.
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Preemptive analgesia studies have provided mixed results, some showing benefit and others no benefit, whereas others have shown small differences that are probably not clinically useful. There is no consensus yet about whether preemptive analgesia is a clinically useful tool. ⋯ A new definition of preemptive analgesia is proposed that accommodates the need for a broader definition. Recently published trials confirm that confusion exists about what preemptive analgesia is, how to distinguish it from simple analgesia, and how to design trials that truly assess preemptive analgesia, defined as analgesia that is capable of modifying the central excitatory responses.