Anesthesiology
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Randomized Controlled Trial Clinical Trial
An evaluation of the effect of anesthetic technique on reproductive success after laparoscopic pronuclear stage transfer. Propofol/nitrous oxide versus isoflurane/nitrous oxide.
Laparoscopic pronuclear stage transfer (PROST) is the preferred method of embryo transfer after in vitro fertilization in many infertility programs. There are scant data to recommend the use or avoidance of any particular anesthetic agent for use in women undergoing this procedure. The authors hypothesized that propofol would be an ideal anesthetic for laparoscopic PROST because of its characteristic favorable recovery profile that includes minimal sedation and a low incidence of postoperative nausea and vomiting. The purpose of the study was to compare propofol and isoflurance with respect to postanesthetic recovery and pregnancy outcomes after laparoscopic PROST. ⋯ Propofol/nitrous oxide anesthesia was associated with lower clinical and ongoing pregnancy rates compared with isoflurane/nitrous oxide anesthesia.
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Clinical Trial Controlled Clinical Trial
Distribution of cerebral blood flow during anesthesia with isoflurane or halothane in humans.
Halothane and isoflurane have been shown to induce disparate effects on different brain structures in animals. In humans, various methods for measuring cerebral blood flow (CBF) have produced results compatible with a redistribution of CBF toward deep brain structures during isoflurane anesthesia in humans. This study was undertaken to examine the effects of halothane and isoflurance on the distribution of CBF. ⋯ There is a difference in the human rCBF distribution between halothane and isoflurane with higher relative flows in subcortical regions during isoflurane anesthesia. However, despite this redistribution, isoflurane anesthesia resulted in a lower mean CBFxenon than did anesthesia with halothane.
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Hospitalized patients outside of the operating room frequently require emergency airway management. This study investigates complications of emergency airway management in critically ill adults, including: (1) the incidence of difficult and failed intubation; (2) the frequency of esophageal intubation; (3) the incidence of pneumothorax and pulmonary aspiration; (4) the hemodynamic consequences of emergent intubation, including death, during and immediately following intubation; and (5) the relationship, if any, between the occurrence of complications and supervision of the intubation by an attending physician. ⋯ In critically ill patients, emergency tracheal intubation is associated with a significant frequency of major complications. In this study, complications were not increased when intubations were accomplished without the supervision of an attending physician as long as the intubation was carried out or supervised by an individual skilled in airway management. Mortality associated with emergent tracheal intubation is highest in patients who are hemodynamically unstable and receiving vasopressor therapy before intubation.
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Numerous classes of anesthetic agents have been shown to enhance the effects mediated by the postsynaptic gamma-aminobutyric acid A (GABAA) receptor-coupled chloride channel in the mammalian central nervous system. However, presynaptic actions of anesthetics potentially relevant to clinical anesthesia remain to be clarified. Therefore, in this study, the effects of intravenous and volatile anesthetics on both the uptake and the depolarization-evoked release of GABA in the rat striatum were investigated. ⋯ These results indicate that most of the intravenous but not the volatile anesthetics inhibit the specific high-affinity 3H-GABA uptake process in vitro in striatal nerve terminals. However, this action was observed at clinically relevant concentrations only for propofol and etomidate. In contrast, the depolarization-evoked 3H-GABA release was not affected by anesthetics. Together, these data suggest that inhibition of GABA uptake, which results in synaptic GABA accumulation, might contribute to propofol and etomidate anesthesia.
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Both halothane and isoflurane evoke cerebral vasodilation. One of the potential mechanisms for arterial vasodilation is enhanced K+ efflux resulting from an increased opening frequency of membrane K+ channels. The current study was designed to determine the effects of volatile anesthetics on K+ channel current in single vascular smooth muscle cells isolated from dog cerebral arteries. ⋯ Halothane and isoflurane suppress the activity of K+ channels in canine cerebral arterial cells. These results suggest that mechanisms other than K+ channel opening likely mediate volatile anesthetic-induced vasodilation.