Anesthesiology
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Randomized Controlled Trial Clinical Trial
Epidural neostigmine produces analgesia but also sedation in women after cesarean delivery.
Intrathecal neostigmine produces analgesia but also nausea, limiting its utility. In contrast, epidural administration of neostigmine has been suggested to produce postoperative analgesia without nausea in nonpregnant patients. The purpose of this study was to examine the dose range for efficacy and side effects of epidural neostigmine in women at cesarean delivery receiving combined spinal-epidural anesthesia. ⋯ Epidural neostigmine produced modest analgesia in women after cesarean delivery. In contrast with previous reports, which focused primarily on nausea, these data suggest that epidural neostigmine can also produce mild sedation for several hours. These data suggest a limited role for single bolus-administration epidural neostigmine for analgesia after cesarean delivery. They also support future study of epidural neostigmine for obstetric analgesia.
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Randomized Controlled Trial Clinical Trial
Epidural anesthesia, hypotension, and changes in intravascular volume.
The most common side effect of epidural or spinal anesthesia is hypotension with functional hypovolemia prompting fluid infusions or administration of vasopressors. Short-term studies (20 min) in patients undergoing lumbar epidural anesthesia suggest that plasma volume may increase when hypotension is present, which may have implications for the choice of treatment of hypotension. However, no long-term information or measurements of plasma volumes with or without hypotension after epidural anesthesia are available. ⋯ Thoracic epidural anesthesia per se does not lead to changes in blood volumes despite a reduction in blood pressure. When fluid is infused, there is a dilution, and the fluid initially seems to be located centrally. Because administration of hydroxyethyl starch and ephedrine has similar hemodynamic effects, the latter may be preferred in patients with cardiopulmonary diseases in which perioperative fluid overload is undesirable.
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Randomized Controlled Trial Clinical Trial
An investigation to dissociate the analgesic and anesthetic properties of ketamine using functional magnetic resonance imaging.
Anatomic sites within the brain, which activate in response to noxious stimuli, can be identified with the use of functional magnetic resonance imaging. The aim of this study was to determine whether the analgesic effects of ketamine could be imaged. ⋯ The analgesic effect can be measured within a more global effect of ketamine as shown by auditory and motor tasks, and the analgesia produced by ketamine occurs with a smaller degree of cortical processing in pain-related regions.
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Clinical Trial
Mixed-effects modeling of the intrinsic ventilatory depressant potency of propofol in the non-steady state.
Despite the ubiquitous use of propofol for anesthesia and conscious sedation and numerous publications about its effect, a pharmacodynamic model for propofol-induced ventilatory depression in the non-steady state has not been described. To investigate propofol-induced ventilatory depression in the clinically important range (at and below the metabolic hyperbola while carbon dioxide is accumulating because of drug-induced ventilatory depression), the authors applied indirect effect modeling to Paco2 data at a fraction of inspired carbon dioxide of 0 during and after administration of propofol. ⋯ Propofol at common clinical concentrations is a potent ventilatory depressant. An indirect response model accurately described the magnitude and time course of propofol-induced ventilatory depression. The indirect response model can be used to optimize propofol administration to reduce the risk of significant ventilatory depression.