Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2012
The volatile anesthetic isoflurane prevents ventilator-induced lung injury via phosphoinositide 3-kinase/Akt signaling in mice.
Mechanical ventilation leads to ventilator-induced lung injury in animals, and can contribute to acute lung injury/acute respiratory distress syndrome in humans. Acute lung injury/acute respiratory distress syndrome currently causes an unacceptably high rate of morbidity and mortality among critically ill patients. Volatile anesthetics have been shown to exert anti-inflammatory and organ-protective effects in vivo. We investigated the effects of the volatile anesthetic isoflurane on lung injury during mechanical ventilation. ⋯ Inhalation of isoflurane during mechanical ventilation protects against lung injury by preventing proinflammatory responses. This protection is mediated via phosphoinositide 3-kinase/Akt signaling.
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Dead space is the portion of a tidal volume that does not participate in gas exchange because it does not get in contact with blood flowing through the pulmonary capillaries. It is commonly calculated using volumetric capnography, the plot of expired carbon dioxide (CO(2)) versus tidal volume, which is an easy bedside assessment of the inefficiency of a particular ventilatory setting. ⋯ Therefore, the results obtained by Bohr's and Enghoff's formulas have different physiological meanings and clinicians must be conscious of such differences when interpreting patient data. In this article, we describe the rationale of dead space measurements by volumetric capnography and discuss its main clinical implications and the misconceptions surrounding it.
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Anesthesia and analgesia · Apr 2012
Intravenous lipid emulsion only minimally influences bupivacaine and mepivacaine distribution in plasma and does not enhance recovery from intoxication in pigs.
The reported successful use of IV lipid emulsions in local anesthetic intoxications is thought to be due to lipid sequestration of local anesthetics. However, controlled efficacy studies were lacking, and other mechanisms of action have also been suggested. We investigated the effect of lipid infusion on plasma concentrations and cardiovascular effects of 2 local anesthetics differing in lipophilicity, bupivacaine, and mepivacaine. ⋯ Lipid emulsion neither had any measurable effect on the disposition of the studied local anesthetics in plasma, nor did it improve the rate of recovery from intoxication by either local anesthetic as measured by hemodynamic variables.