Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Cardiac outcome after peripheral vascular surgery. Comparison of general and regional anesthesia.
Despite evidence that regional anesthesia may be associated with fewer perioperative complications than general anesthesia, most studies that have compared cardiac outcome after general or regional anesthesia alone have not shown major differences. This study examines the impact of anesthetic choice on cardiac outcome in patients undergoing peripheral vascular surgery who have a high likelihood of associated coronary artery disease. ⋯ The choice of anesthesia, when delivered as described, does not significantly influence cardiac morbidity and overall mortality in patients undergoing peripheral vascular surgery.
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Randomized Controlled Trial Clinical Trial
Hemodynamic responses to intravascular injection of epinephrine-containing epidural test doses in adults during general anesthesia.
Epidural anesthesia is sometimes initiated during general anesthesia, yet few data exist concerning efficacy of epinephrine-containing test doses. ⋯ Hemodynamic responses to intravascular injection of test doses vary with dose of epinephrine and depth and type of general anesthetic used. Thus, the 15 micrograms epinephrine contained in the standard test dose may not be sufficient during all anesthetic conditions.
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Randomized Controlled Trial Comparative Study Clinical Trial
Propofol fails to attenuate the cardiovascular response to rapid increases in desflurane concentration.
A rapid increase in desflurane concentration to greater than 1 MAC transiently increases heart rate, arterial blood pressure, and circulating catecholamine concentration. Because propofol decreases sympathetic outflow, it was hypothesized that propofol would blunt these responses. ⋯ Although able to blunt the increase in epinephrine concentration, propofol 2 mg.kg-1 propofol does no attenuate the transient cardiovascular response to a rapid increase in desflurane concentration to greater than 1 MAC.
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Comparative Study
Intravenous opioids stimulate norepinephrine and acetylcholine release in spinal cord dorsal horn. Systematic studies in sheep and an observation in a human.
Opioids produce analgesia by direct effects as well as by activating neural pathways that release nonopioid transmitters. This study tested whether systematically administered opioids activate descending spinal noradrenergic and cholinergic pathways. ⋯ These results support functional studies that indicate that systematically administered opioids cause spinal norepinephrine and acetylcholine release by a naloxone-sensitive mechanism. Idazoxan blockade of morphine's effects on cerebrospinal fluid norepinephrine was unexpected, and suggests that both norepinephrine and acetylcholine release in the spinal cord may be regulated by alpha 2-adrenoceptors. Microdialysis experiments suggest increased norepinephrine and acetylcholine levels in cerebrospinal fluid resulted from intravenous morphine-induced activation of bulbospinal pathways.
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Comparative Study
New ultrathin-walled endotracheal tube with a novel laryngeal seal design. Long-term evaluation in sheep.
A new endotracheal tube (ETT) was fabricated and tested in sheep. It had no tracheal cuff; airway seal was achieved at the level of the glottis through a no-pressure seal made of "gills"; the laryngeal portion was oval-shaped; and the wall thickness was reduced to 0.2 mm. ⋯ The novel, no-pressure seal design of the new ETT is highly effective in preventing air leak and aspiration. It causes no significant tracheal injury.