Anesthesiology
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Randomized Controlled Trial Clinical Trial
Duration of anesthesia before muscle relaxant injection influences level of paralysis.
Dosage guidelines for muscle relaxants are based on dose-response studies, normally performed after several minutes of stable nitrous oxide (N O)-opioid anesthesia. However, relaxants are used immediately after induction of anesthesia. The study was designed to determine the influence of the duration of anesthesia and N O on the onset time at the adductor pollicis (AP) and the corrugator supercilii (CS) muscles of maximum neuromuscular blockade after mivacurium. ⋯ Duration of anesthesia and N O before mivacurium injection affect intensity of neuromuscular blockade but not onset time. Neuromuscular blockade obtained at the AP after several minutes of stable anesthesia with N O is greater than immediately after induction. This explains in part the discrepancy between the measured ED and the intubating dose.
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Comparative Study
Comparing clinical productivity of anesthesiology groups.
Intergroup comparisons of clinical productivity are important for strategic planning and evaluation of clinical and business operations. However, in a preliminary study, comparisons of two anesthesiology groups using "per full-time equivalent" measurements were confounded by different concurrencies or staffing ratios, whereas measurements based on "per operating room (OR) site," "per case," and "billed American Society of Anesthesiologists (ASA) units per hour of care" permitted meaningful comparisons despite differing concurrencies. The purpose of this study was to determine whether these measurements would allow for meaningful comparisons when applied to multiple groups. ⋯ This study demonstrates a method of comparing departmental clinical productivity between anesthesiology groups. Private-practice groups provided care for cases of shorter duration than academic groups. This difference was evident in several productivity measurements.
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Local anesthetics were suggested to have a potential for neurotoxicity in both clinical reports and laboratory experiments. Growing neurons have been shown to be susceptible to the toxic effects of local anesthetics in culture. These findings have generated the interest in factors that would rescue the neurons affected by the neurotoxicity of local anesthetics. ⋯ The NTFs-brain-derived neurotrophic factor, glial-derived neurotrophic factor, and neurotrophin 3-were demonstrated to support the reversibility of lidocaine-induced growth cone collapse in primary cultured sensory neurons, an effect that was concentration- and time-dependent. Because similar effects were observed after tetracaine washout, the supporting effects of NTFs may not be specific to lidocaine.
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Bupivacaine produces skeletal muscle damage in clinical concentrations. It has been suggested that this may be caused by an increased intracellular level of [Ca2+]. Therefore, the aim of this study was to investigate direct intracellular effects of bupivacaine on Ca2+ release from the sarcoplasmic reticulum (SR), on Ca2+ uptake into the SR, and on Ca2+ sensitivity of the contractile proteins. ⋯ These data reveal that bupivacaine does not only induce Ca2+ release from the SR, but also inhibits Ca2+ uptake by the SR, which is mainly regulated by SR Ca2+ adenosine triphosphatase activity. It also has a Ca2+ -sensitizing effect on the contractile proteins. These mechanisms result in increased intracellular [Ca2+] concentrations and may thus contribute to its pronounced skeletal muscle toxicity.