Anesthesiology
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Chronic exposure to cigarette smoke produces profound changes in physiology that may alter responses to perioperative interventions and contribute to perioperative morbidity. Because of smoke-free policies in healthcare facilities, all smokers undergoing surgery are abstinent from cigarettes for at least some period of time so that all are in various stages of recovery from the effects of smoke. ⋯ This review examines current knowledge regarding how both short-term (duration ranging from hours to weeks) and long-term smoking cessation affects selected physiology and pathophysiology of particular relevance to perioperative outcomes and how these changes affect perioperative risk. It will also consider current evidence regarding how nicotine replacement therapy, a valuable adjunct to help patients maintain abstinence, may affect perioperative physiology.
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Few studies have examined the use of ultrasound for sciatic nerve localization. The authors evaluated the usefulness of low-frequency ultrasound in identifying the sciatic nerve at three locations in the lower extremity and in guiding needle advancement to target before nerve stimulation. ⋯ These preliminary data show that a curved 2- to 5-MHz ultrasound probe provides good quality sciatic nerve imaging in the gluteal, infragluteal, and proximal thigh locations. Ultrasound-assisted sciatic nerve localization is potentially valuable for clinical sciatic nerve blocks.
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The endocannabinoid system includes G-protein-coupled cannabinoid receptors, the endocannabinoids N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol, and multiple enzymes involved in the biosynthesis and degradation of endocannabinoids, including the anandamide metabolizing enzyme fatty acid amide hydrolase. Endocannabinoids play an important role in the physiologic control of sleep, pain processing, and emesis. The authors therefore investigated the effects of general anesthesia on the endocannabinoid system in humans. ⋯ General anesthesia influences the endocannabinoid system in a drug-dependent way, which may explain side effects of general anesthetics such as psychomimetic and antiemetic properties of propofol and the high incidence of postoperative nausea and vomiting after volatile anesthetics. These findings suggest new targets for anesthetic drug development.
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Comparative Study
Comparative effects of vaporized perfluorohexane and partial liquid ventilation in oleic acid-induced lung injury.
It is currently not known whether vaporized perfluorohexane is superior to partial liquid ventilation (PLV) for therapy of acute lung injury. In this study, the authors compared the effects of both therapies in oleic acid-induced lung injury. ⋯ Although the use of 5% vaporized perfluorohexane permitted the authors to reduce pressures needed to stabilize the lungs and was associated with better histologic findings than were PLV and GV, none of these perfluorocarbon therapies improved gas exchange or lung mechanics as compared with GV.