Anesthesiology
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Chronic pain conditions may result from peripheral nerve injury, chronic peripheral inflammation, or sensory ganglia inflammation. However, inflammatory processes may also contribute to peripheral nerve injury responses. To isolate the contribution of local inflammation of sensory ganglia to chronic pain states, the authors previously developed a rat model in which long-lasting pain is induced by inflaming sensory ganglia without injuring the neurons. This results in prolonged mechanical pain, local increases in proinflammatory cytokines, increased neuronal hyperexcitability, and abnormal spontaneous activity. ⋯ Neuronal inflammation per se, in the absence of nerve injury, causes large increases in Na channel density and enhanced excitability. The unusual finding of increased K current may reflect regulation of excitability in the face of such large increases in Na current.
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Randomized Controlled Trial Multicenter Study
Skin reactions to intradermal neuromuscular blocking agent injections: a randomized multicenter trial in healthy volunteers.
Numerous reports confirm the performance of intradermal tests for the diagnosis of anaphylaxis during anesthesia; however, there is controversy over their diagnostic value regarding the newer neuromuscular blocking agents (NMBAs). ⋯ The aminosteroidal NMBAs pancuronium, vecuronium, and rocuronium and the benzylisoquinoline cisatracurium have a similar potency to induce a nonspecific skin reactivity. If the criteria for positivity and the maximal concentrations of the commercially available compounds recommended by French practice guidelines are used, the risk of false-positive results is limited, and only minor modifications of these recommendations could be suggested. A slight reduction in the maximal concentration used for rocuronium from 1:100 to 1:200 and an increase from 1:1,000 to 1:200 for mivacurium can be proposed.
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To eliminate the influence of hydrostatic pressure, proper transducer positions for central venous pressure and pulmonary artery wedge pressure are at the uppermost blood levels of right atrium (RA) and left atrium (LA). This study was performed to investigate accurate reference levels of central venous pressure and pulmonary artery wedge pressure in the supine position. ⋯ In the supine position, a central venous pressure transducer should be positioned approximately 4.6 cm higher than a pulmonary artery wedge pressure transducer. The external reference level for central venous pressure seems to be at approximately four fifths of the AP diameter of the thorax from the back, and that for pulmonary artery wedge pressure seems to be at approximately three fifths of the AP diameter.
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Comparative Study
Resuscitation with recombinant hemoglobin rHb2.0 in a rodent model of hemorrhagic shock.
Hemoglobin solutions combine volume effect, oxygen-carrying capacity, and vasoactive properties, the latter facilitating restoration of global hemodynamics but endangering microvascular resuscitation. Hemoglobin-evoked vasoconstriction probably is due to nitric oxide scavenging, which can be reduced by genetic modifications of the heme pocket. This study compares resuscitation with a nonhemoglobin colloid and two recombinant hemoglobin solutions with wild-type and reduced nitric oxide-scavenging capacity. ⋯ After resuscitation with rHb1.1, arteriolar vasoconstriction quickly restored MAP, but this was achieved at the expense of FCD. In contrast, after resuscitation with rHb2.0, the recovery of MAP could be translated into a significantly improved FCD.
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QX-314 is a quaternary lidocaine derivative considered to be devoid of clinically useful local anesthetic activity. However, several reports document that extracellular QX-314 application affects action potentials. Hence, the authors tested the hypothesis that QX-314 could produce local anesthesia in animal models in vivo. ⋯ In a randomized, controlled laboratory study, the quaternary lidocaine derivative, QX-314, concentration-dependently and reversibly produced long-lasting local anesthesia with a slow onset in animal models in vivo. The authors' results raise the possibility that quaternary ammonium compounds may produce clinically useful local anesthesia of long duration in humans and challenge the conventional notion that these agents are ineffective when applied extracellularly.