Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2013
Brief report: leaking esophageal probe may lead to false ventilator settings when guiding positive end-expiratory pressure by transpulmonary pressure.
Esophageal pressure (Pes) is a surrogate for intrapleural pressure. Measuring Pes during mechanical ventilation allows for positive end-expiratory pressure adjustments by transpulmonary pressure (PL), which has been shown to improve oxygenation and outcome in acute respiratory distress syndrome patients. In morbidly obese patients, we saw progressively increasing PL measurements, although airway pressure (Paw), intra-abdominal pressure, and patient position did not change. On further examination, we determined that the gradual increases of PL were artifacts caused by a leak in the pressure probes, which resulted in underestimation of Pes and overestimation of PL as derived from the equation Paw - Pes = PL.
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Anesthesia and analgesia · Sep 2013
Comparative StudyThe myotoxic effect of bupivacaine and ropivacaine on myotubes in primary mouse cell culture and an immortalized cell line.
The 2 local anesthetics (LAs) bupivacaine and ropivacaine have acute cytotoxic effects on different tissues. In this respect, LA-induced myotoxicity has been subject to various studies; however, the exact mechanisms are still not fully understood. Most in vitro studies use immortalized cell lines because of feasibility. Thus, establishing a primary cell line might result in more accurate results. In this study, we examined the effects of immortalization on bupivacaine- and ropivacaine-induced myotoxicity in vitro. ⋯ Primary skeletal muscle cells are more vulnerable to LAs than immortalized cells. The higher myotoxic potential of bupivacaine compared with ropivacaine in vivo can be reproduced in vitro. Incubation time has an influence on cell survival.
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Anesthesia and analgesia · Sep 2013
Glucose use in fasted rats under sevoflurane anesthesia and propofol anesthesia.
We previously reported the marked differences in the effects of sevoflurane anesthesia and propofol anesthesia on glucose use in fed rats; however, we could not elucidate mechanisms underlying the differences. ⋯ Sevoflurane anesthesia attenuates glucose-induced insulin secretion without affecting basic insulin secretion, while propofol anesthesia enhances insulin secretion. Propofol anesthesia exaggerates insulin-resistive conditions, whereas sevoflurane anesthesia dose not impair insulin sensitivity; there may be a possible association of TNF-α with insulin-resistive conditions under propofol anesthesia.
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A well-known complication of peripheral nerve block is peripheral nerve injury, whether from the needle or toxicity of the medication used. In this study, we sought to determine the extent of damage that results from intrafascicular injection of various commonly used local anesthetics (LAs). ⋯ Frequently used LAs at traditional concentrations are toxic to and can injure the peripheral nerve. Any combination of motor and/or sensory sequelae may result due to the varying fascicular topography of a nerve.