Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2009
Randomized Controlled Trial Comparative StudyThe median effective dose of bupivacaine, levobupivacaine, and ropivacaine after intrathecal injection in lower limb surgery.
Intrathecal anesthesia is commonly used for lower limb surgery. Bupivacaine, levobupivacaine, and ropivacaine have all been used as intrathecal drugs, but their relative potency in this context has not been fully determined. In this study, we determined the median effective dose (ED(50)) of these three local anesthetics for intrathecal anesthesia in lower limb surgery and hence their relative potencies. ⋯ This study suggests that in intrathecal anesthesia for lower limb surgery, ropivacaine is less potent than levobupivacaine and bupivacaine, whereas the potency is similar between levobupivacaine and bupivacaine.
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Anesthesia and analgesia · Oct 2009
ReviewThe myotonias and susceptibility to malignant hyperthermia.
Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle in which volatile anesthetics trigger a sustained increase in intramyoplasmic Ca(2+) via release from sarcoplasmic reticulum and, possibly, entry from the extracellular milieu that leads to hypermetabolism, muscle rigidity, rhabdomyolysis, and death. Myotonias are a class of myopathies that result from gene mutations in various channels involved in skeletal muscle excitation-contraction coupling and sarcolemmal excitability, and unusual DNA sequence repeats that result in the inability of many proteins, including skeletal muscle channels that affect excitability, to undergo proper splicing. ⋯ We conclude that patients with these myopathies have a risk of developing MH that is equivalent to that of the general population with one potential exception, hypokalemic periodic paralysis. Despite the fact that there are no clinical reports of MH developing in patients with hypokalemic periodic paralysis, for theoretical reasons we cannot be as certain in estimating their risk of developing MH, even though we believe it is low.
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Anesthesia and analgesia · Oct 2009
Randomized Controlled Trial Comparative StudyA comparison of postoperative throat and neck complaints after the use of the i-gel and the La Premiere disposable laryngeal mask: a double-blinded, randomized, controlled trial.
Many supralaryngeal airway devices are available. Because of the absence of an inflatable cuff, we hypothesized that use of the i-gel should produce fewer postoperative throat and neck complaints compared with a standard disposable laryngeal mask (LM). ⋯ In this randomized study, the i-gel supraglottic device resulted in a lower incidence of throat and neck complaints than the La Premiere LM airway.
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Anesthesia and analgesia · Oct 2009
Randomized Controlled Trial Comparative StudyNeuromuscular block differentially affects immobility and cortical activation at near-minimum alveolar concentration anesthesia.
Anesthesia-induced immobility and cortical suppression are governed by anatomically separate, but interacting, areas of the central nervous system. Consequently, larger volatile anesthetic concentrations are required to suppress cortical activation than to abolish movement in response to noxious stimulation. We examined the effect of decreased afferent input, as produced by neuromuscular block (NMB), on immobility and cortical activation, as measured by bispectral index (BIS) of the electrocardiogram, in the presence of noxious stimulation during approximately minimum alveolar concentrations (MACs) of desflurane anesthesia. ⋯ Both succinylcholine and mivacurium enhanced immobility during near-MAC anesthesia. All treatments were associated with a small, although significant, BIS increase in response to noxious stimulation, whereas succinylcholine increased BIS independently of noxious stimulation or EMG(BIS). Mivacurium suppressed autonomic response to a noxious event.
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Anesthesia and analgesia · Oct 2009
ReviewMalignant hyperthermia, coexisting disorders, and enzymopathies: risks and management options.
Clinical episodes and abnormal laboratory tests compatible with a diagnosis of malignant hyperthermia have been observed in patients with a diversity of syndromes, enzymopathies, and coexisting disorders thereby raising the likelihood of causal associations and heightened perioperative risk in others carrying a shared diagnosis. In the present review, we survey available published series, case reports, and the results of contracture testing in patients identified by others to be potentially predisposed to malignant hyperthermia. For most conditions, evidence for a causal relationship with malignant hyperthermia susceptibility is weak. The review concludes with suggestions for clinical management when evidence for or against an association is uncertain.