Minerva anestesiologica
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Minerva anestesiologica · Oct 2016
Case ReportsWhole-exome sequencing of a family with local anesthetic resistance.
Local anesthetics (LA) work by blocking sodium conductance through voltage-gated sodium channels. Complete local anesthetic resistance is infrequent, and the cause is unknown. Genetic variation in sodium channels is a potential mechanism for local anesthetic resistance. A patient with a history of inadequate loss of sensation following LA administration underwent an ultrasound-guided brachial plexus nerve block with a complete failure of the block. We hypothesized that LA resistance is due to a variant form of voltage-gated sodium channel. ⋯ We identified a genetic variant that is associated with LA resistance in the gene encoding for Nav1.5. We also demonstrate that Nav1.5 is present in human peripheral nerves to support the plausibility that an abnormal form of the Nav1.5 protein could be responsible for the observed local anesthetic resistance.
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Minerva anestesiologica · Oct 2016
Observational StudyEffects of passive leg raising on microvascular venous compartment in critically ill patients.
Even though fluid loading is thought to improve organ perfusion, the way in which it does so remains unclear. We assessed how the microvascular bed in skeletal muscle reacts to passive leg raising in patients with and without sepsis or septic shock. ⋯ Our study provides evidence that macrocirculatory parameters are unreliable to derive measurements of stressed and unstressed volumes. Our results indicate that in septic shock, the enlargement of the unstressed volume associated with passive leg raising induces loss of fluids to the interstitium, thus leaving organ perfusion unchanged or worse.