Anesthesiology
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Comparative Study
Comparison between bispectral index and patient state index as measures of the electroencephalographic effects of sevoflurane.
The Bispectral Index (BIS) and the Patient State Index (PSI) quantify depth of anesthesia by analyzing the electroencephalogram. The authors examined the response of BIS and PSI to sevoflurane anesthesia. ⋯ The BIS reacted faster to changes in sevoflurane concentrations, whereas the PSI made better use of the predefined index range. However, despite major differences in their algorithms and minor differences in their dose-response relations, both PSI and BIS predicted depth of sevoflurane anesthesia equally well.
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Comparative Study
Capsaicin combined with local anesthetics preferentially prolongs sensory/nociceptive block in rat sciatic nerve.
Transient receptor potential vanilloid 1 channels integrate nociceptive stimuli and are predominantly expressed by unmyelinated C-fiber nociceptors, but not low-threshold mechanoreceptive sensory or motor fibers. A recent report showed that the transient receptor potential vanilloid 1 channel agonist capsaicin allows a hydrophilic quaternary ammonium derivative of lidocaine, QX-314, to selectively block C fibers without motor block. The authors tested whether a similar differential block would be produced using amphipathic N-methyl amitriptyline, amitriptyline, bupivacaine, or lidocaine, either alone or together with 0.05% capsaicin, in a rat sciatic nerve block model. ⋯ Both tertiary amine local anesthetics and their quaternary ammonium derivatives can elicit a predominantly sensory/nociceptor selective block when followed by injection of capsaicin. The combined application of transient receptor potential vanilloid 1 channel agonists and various local anesthetics or their quaternary ammonium derivatives is an appealing strategy to achieve a long-lasting differential block in regional analgesia.
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Selective blockade of spinal sigma(1) receptors (Sig-1R) suppresses nociceptive behaviors in the mouse formalin test. The current study was designed to verify whether intrathecal Sig-1R antagonists can also suppress chronic neuropathic pain. ⋯ These results demonstrate that spinal Sig-1Rs play a critical role in both the induction of mechanical allodynia and the activation of spinal N-methyl-d-aspartate receptors in CCI rats and suggest a potential therapeutic role for the use of Sig-1R antagonists in the clinical management of neuropathic pain.
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Comparative Study
Hypercapnic acidosis attenuates lung injury induced by established bacterial pneumonia.
Hypercapnic acidosis protects against lung injury after ischemia-reperfusion, endotoxin-induced and ventilation-induced lung injury. The effects of hypercapnic acidosis in the setting of established pulmonary sepsis are not known. The authors investigated whether hypercapnic acidosis -- induced by adding carbon dioxide to inspired gas -- would be beneficial or deleterious in established Escherichia coli pneumonia in an in vivo model, in the presence and absence of antibiotic therapy. ⋯ Hypercapnic acidosis reduced the magnitude of the lung injury induced by established E. coli pneumonia.