Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2014
Comparative StudyChanges in plasma orexin-a levels in sevoflurane-remifentanil anesthesia in young and elderly patients undergoing elective lumbar surgery.
Delayed emergence from general anesthesia frequently occurs in elderly patients, but the reason is not clear. Orexin has been shown to be involved in arousal from general anesthesia. In this study, we examined plasma orexin-A levels in both elderly and young patients during the anesthesia arousal cycle. ⋯ Plasma orexin-A levels are not responsible for the delayed emergence from general anesthesia in elderly patients.
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Anesthesia and analgesia · Apr 2014
Intrathecal Injection of JWH015 Attenuates Remifentanil-Induced Postoperative Hyperalgesia by Inhibiting Activation of Spinal Glia in a Rat Model.
Hyperalgesia and neuroinflammation are associated with glia, which consists of macroglia and microglia. In this study, we used a selective cannabinoid receptor type 2 (CB2) agonist JWH015 to investigate remifentanil-induced postoperative hyperalgesia. ⋯ The activation of glia, the production of proinflammatory cytokines, and the expression of CB2 and p-NR2B in the spinal dorsal horn increase significantly during the process of remifentanil-induced hyperalgesia. These changes can be regulated by pretreatment with JWH015, which may be the main mechanism underlying the antihyperalgesia effects of JWH015.
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Anesthesia and analgesia · Apr 2014
A decrease in spatially resolved near-infrared spectroscopy-determined frontal lobe tissue oxygenation by phenylephrine reflects reduced skin blood flow.
Spatially resolved near-infrared spectroscopy-determined frontal lobe tissue oxygenation (ScO2) is reduced with administration of phenylephrine, while cerebral blood flow may remain unaffected. We hypothesized that extracranial vasoconstriction explains the effect of phenylephrine on ScO2. ⋯ These findings suggest that a phenylephrine-induced decrease in ScO2, as determined by INVOS-4100 near-infrared spectroscopy, reflects vasoconstriction in the extracranial vasculature rather than a decrease in cerebral oxygenation.
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Anesthesia and analgesia · Apr 2014
Intraneural and Perineural Inflammatory Changes in Piglets After Injection of Ultrasound Gel, Endotoxin, 0.9% NaCl, or Needle Insertion without Injection.
Ultrasound gel nerve inflammation has been reported. We evaluated the extent and nature of inflammation after gel injection with endotoxin (positive), saline, or dry needle puncture (negative) controls after peripheral blocks in piglets. ⋯ Perineural gel injections cause significant inflammation. The lack of cytokines suggests injectate-related changes rather than mechanical trauma.
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Anesthesia and analgesia · Apr 2014
When does apparatus dead space matter for the pediatric patient?
Physiologic dead space is defined as the volume of the lung where gas exchange does not occur. Apparatus dead space increases dead space volume, causing either increased PaCO2 or the need to increase minute ventilation to maintain normocapnia. Children are especially vulnerable because small increases in apparatus dead space can significantly increase dead space to tidal volume ratio (Vd/Vt). ⋯ Similarly, RR required to maintain PaCO2 of 40 mm·Hg increased exponentially with increasing dead space. Increasing apparatus Vd can lead to exponential increases in PaCO2 and/or RR required to maintain normal PaCO2. The effect on PaCO2 is less as patient weight increases, but these data suggest it can be significant for typical circuit components up to at least 17 kg or aged 36 months.