Anesthesiology
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Randomized Controlled Trial Multicenter Study
Effect of patient-controlled perineural analgesia on rehabilitation and pain after ambulatory orthopedic surgery: a multicenter randomized trial.
Efficacy of continuous perineural and patient-controlled ropivacaine infusion at home after orthopedic surgery was compared with patient-controlled intravenous morphine for functional recovery and postoperative analgesia in a multicenter randomized trial. ⋯ After ambulatory orthopedic surgery, 0.2% ropivacaine delivered as a perineural infusion using a disposable elastomeric pump with patient-controlled anesthesia bolus doses optimizes functional recovery and pain relief while decreasing the consumption of rescue analgesics and ropivacaine, and the number of adverse events.
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Vasopressin, synthesized in the hypothalamus, is released by increased plasma osmolality, decreased arterial pressure, and reductions in cardiac volume. Three subtypes of vasopressin receptors, V1, V2, and V3, have been identified, mediating vasoconstriction, water reabsorption, and central nervous system effects, respectively. Vasopressin and its analogs have been studied intensively for the treatment of states of "relative vasopressin deficiency," such as sepsis, vasodilatory shock, intraoperative hypotension, and cardiopulmonary resuscitation. ⋯ Bolus application of 1 mg terlipressin, the V1 agonist, reverses refractory hypotension in anesthetized patients and has been studied in patients with septic shock and chronic liver failure. During cardiopulmonary resuscitation, a 40-U bolus dose of vasopressin may be considered to replace the first or second bolus of epinephrine regardless of the initial rhythm. The side effects of vasopressin and its analogs must be further characterized.
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The skin microcirculation may be evaluated noninvasively by laser Doppler flowmetry and iontophoresis with acetylcholine and sodium nitroprusside. Wavelet transform of the perfusion signal shows periodic oscillations of five characteristic frequencies in the interval 0.0095-1.6 Hz. The aim of the current study was to investigate alterations in skin microcirculation induced by brachial plexus block, with emphasis on the periodic oscillations. ⋯ Alterations in skin microcirculation induced by brachial plexus block can be evaluated by wavelet transform of the laser Doppler flowmetry signal. Brachial plexus block reduces the oscillatory components within the 0.0095- to 0.021- and 0.021- to 0.052-Hz intervals of the perfusion signal. These alterations are related to inhibition of sympathetic activity and a possible impairment of endothelial function.
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Anesthetic and ischemic preconditioning share similar signal transduction pathways. The authors tested the hypothesis that the beta1-adrenergic signal transduction pathway mediates anesthetic and ischemic preconditioning in vivo. ⋯ The results demonstrate that anesthetic preconditioning is mediated by the beta1-adrenergic pathway, whereas this pathway is not essential for ischemic preconditioning. These results indicate important differences in the mechanisms of anesthetic and ischemic preconditioning.