Articles: general-anesthesia.
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Anesthesia progress · Jan 2005
ReviewPreemptive analgesia and local anesthesia as a supplement to general anesthesia: a review.
General anesthesia (GA) and local anesthesia (LA) evolved on separate tracks. Procedures that could not be performed under LA were typically conducted under GA. Decoding of afferent linkage of peripheral noxious stimuli has provided important understanding that may change the way we traditionally treat surgical pain. ⋯ General anesthetics can be given in lower minimal alveolar concentration when combined with LA, and recovery characteristics are superior. Increasing evidence suggests that the combined use of GA and LA may reduce the afferent barrage of surgery, and that preemptive analgesia may reduce postoperative pain and should be used in patient care. This article reviews the evidence supporting the combined use of LA or analgesics with GA or sedation to provide improved pain management after surgery.
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Remifentanil (Ultiva), a fentanyl derivative, is an ultra-short acting, nonspecific esterase-metabolised, selective mu-opioid receptor agonist, with a pharmacodynamic profile typical of opioid analgesic agents. Notably, the esterase linkage in remifentanil results in a unique and favourable pharmacokinetic profile for this class of agent. ⋯ Remifentanil is efficacious in combination with intravenous or volatile hypnotic agents, with these regimens generally being at least as effective as fentanyl- or alfentanil-containing regimens in terms of attenuation of haemodynamic, autonomic and somatic intraoperative responses, and postoperative recovery parameters. The rapid offset of action and short context-sensitive half-time of remifentanil, irrespective of the duration of the infusion, makes the drug a valuable opioid analgesic option for use during balanced general inhalational or total intravenous anaesthesia where rapid, titratable, intense analgesia of variable duration, and a fast and predictable recovery are required.
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The neural correlates of consciousness must be identified, but how? Anesthetics can be used as tools to dissect the nervous system. Anesthetics not only allow for the experimental investigation into the conscious-unconscious state transition, but they can also be titrated to subanesthetic doses in order to affect selected components of consciousness such as memory, attention, pain processing, or emotion. A number of basic neuroimaging examinations of various anesthetic agents have now been completed. ⋯ Whereas network interactions have yet to be investigated with ketamine, a thalamocortical and corticocortical disconnection effect during unconsciousness has been found for both suppressive anesthetic agents and for patients who are in the persistent vegetative state. Furthermore, recovery from a vegetative state is associated with a reconnection of functional connectivity. Taken together these intriguing observations offer strong empirical support that the thalamus and thalamocortical reverberant network loop interactions are at the heart of the neurobiology of consciousness.
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There can be few more daunting challenges for the emergency physician than an infant or small child in shock or cardiac arrest. At the best of times, the combination of small veins and abundant subcutaneous tissue makes vascular access difficult or impossible, even in experienced hands. For these situations, the intraosseous vascular access is an easy, rapid and safe alternative. ⋯ Access should be obtained with a commercially available intraosseous needle. All emergency drugs and infusion fluids for intravenous usage can safely be infused via the intraosseous route (except hypertonic solutions) and it is not necessary to adjust drug dosage compared to the intravenous route. To avoid complications caused by the intraosseous needle, such as osteomyelitis, it should be replaced within 2 h by a conventional vascular access.