Anesthesiology
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Randomized Controlled Trial Comparative Study
Intraoperative systolic blood pressure variability predicts 30-day mortality in aortocoronary bypass surgery patients.
Few data support an association between blood pressure variability and clinical outcomes during cardiac surgery. We tested the hypothesis that intraoperative systolic blood pressure variability outside a targeted blood pressure range predicts 30-day mortality in patients undergoing cardiac surgery. ⋯ Intraoperative blood pressure variability is associated with 30-day postoperative mortality in patients undergoing aortocoronary bypass surgery.
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Randomized Controlled Trial Comparative Study
Propofol and remifentanil differentially modulate frontal electroencephalographic activity.
The purpose of this study was to evaluate a new, physiologically inspired method for the analysis of the electroencephalogram during propofol-remifentanil anesthesia. Based on fixed-order autoregressive moving-average modeling, this method was hypothesized to be capable of dissociating the effects that hypnotic and analgesic agents have on brain electrical activity. ⋯ Because Cortical State responds principally to variations in CePROP, it is a potential measure of hypnosis, whereas the dependence of Cortical Input on effect-site remifentanil concentration suggests that it may be useful as a measure of analgesic efficacy and the nociceptive-antinociceptive balance.
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Volume kinetics is a method used for analyzing and simulating the distribution and elimination of infusion fluids. Approximately 50 studies describe the disposition of 0.9% saline, acetated and lactated Ringer's solution, based on repeated measurements of the hemoglobin concentration and (sometimes) the urinary excretion. The slow distribution to the peripheral compartment results in a 50-75% larger plasma dilution during an infusion of crystalloid fluid than would be expected if distribution had been immediate. ⋯ Some of this temporary decrease can be attributed to the anesthesia and probably also to preoperative psychologic stress or dehydration. Crystalloid fluid might be allocated to "nonfunctional" fluid spaces in which it is unavailable for excretion. This amounts to approximately 20-25% during minor (thyroid) surgery.
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Comparative Study
Spinal alpha 2-adrenoceptor-mediated analgesia in neuropathic pain reflects brain-derived nerve growth factor and changes in spinal cholinergic neuronal function.
Spinal alpha2-adrenoceptor stimulation produces analgesia in neuropathic pain states, and this effect in animals is blocked by the inhibitors of brain-derived neurotrophic factor (BDNF) function. In rats, alpha2-adrenoceptor stimulation normally inhibits acetylcholine release, but it excites release after nerve injury. The authors examined the roles of BDNF and excitatory Gs-protein in this change. ⋯ The increased reliance of spinal alpha2 adrenoceptors on cholinergic stimulation to cause analgesia after nerve injury reflects in part a shift from direct inhibition to direct excitation of spinal cholinergic neurons. The authors' results suggest that this shift relies on an interaction with Gs-proteins and BDNF.