The Efficacy and Safety of Dexmedetomidine for Sedation During Surgery Under Epidural or Spinal Anesthesia: A Randomized, Double-Blind, Placebo-Controlled Study

Background: Only a few studies have been reported on the use of dexmedetomidine for sedating surgical patients requiring epidural or spinal anesthesia. We conducted a randomized, double-blind, placebo-controlled, parallel-group study at 12 hospitals in Japan. Methods: Adult patients were randomly allocated to receive an intravenous administration of placebo or dexmedetomidine at 0.067, 0.25, 0.5 or 1.0 μg/kg over 10 min after epidural or spinal anesthesia. All dexmedetomidine groups received dexmedetomidine 0.2–0.7 μg/kg/h to maintain an Observer’s Assessment of Alertness/Sedation Scale (OAA/S) score of ≤ 4; however, propofol was administered to rescue patients who exceeded this score. Surgery was then started 15 min after study drug infusion in patients with OAA/S score of ≤ 4. The primary endpoint was the percentage of patients not requiring rescue propofol to achieve and maintain an OAA/S score of ≤ 4. Results: Of the 120 enrolled and randomized patients, 119 were treated the study: 22 received placebo and 97 received dexmedetomidine (23–25 patients per dose). Significantly more patients did not require propofol in the dexmedetomidine 0.5 and 1.0 μg/kg groups (68.0% and 80.0%, respectively) compared to the placebo group (22.7%) (P = 0.003 and P < 0.001, respectively). Common adverse events (AEs) were protocol-defined respiratory depression, bradycardia and hypotension. There was no significant difference in the incidence of AEs between the dexmedetomidine and the placebo groups. Conclusion: We concluded that loading doses of 0.5 and 1.0 μg/kg dexmedetomidine, followed by an infusion at a rate of 0.2–0.7 μg/kg/h, provide effective and well-tolerated sedation for surgical patients during epidural or spinal anesthesia. Clinical trials.gov identifier: NCT0143895

A local anesthetic, ropivacaine, suppresses activated microglia via a nerve growth factor-dependent mechanism and astrocytes via a nerve growth factor-independent mechanism in neuropathic pain

<p>Abstract</p> <p>Background</p> <p>Local anesthetics alleviate neuropathic pain in some cases in clinical practice, and exhibit longer durations of action than those predicted on the basis of the pharmacokinetics of their blocking effects on voltage-dependent sodium channels. Therefore, local anesthetics may contribute to additional mechanisms for reversal of the sensitization of nociceptive pathways that occurs in the neuropathic pain state. In recent years, spinal glial cells, microglia and astrocytes, have been shown to play critical roles in neuropathic pain, but their participation in the analgesic effects of local anesthetics remains largely unknown.</p> <p>Results</p> <p>Repetitive epidural administration of ropivacaine reduced the hyperalgesia induced by chronic constrictive injury of the sciatic nerve. Concomitantly with this analgesia, ropivacaine suppressed the increases in the immunoreactivities of CD11b and glial fibrillary acidic protein in the dorsal spinal cord, as markers of activated microglia and astrocytes, respectively. In addition, epidural administration of a TrkA-IgG fusion protein that blocks the action of nerve growth factor (NGF), which was upregulated by ropivacaine in the dorsal root ganglion, prevented the inhibitory effect of ropivacaine on microglia, but not astrocytes. The blockade of NGF action also abolished the analgesic effect of ropivacaine on neuropathic pain.</p> <p>Conclusions</p> <p>Ropivacaine provides prolonged analgesia possibly by suppressing microglial activation in an NGF-dependent manner and astrocyte activation in an NGF-independent manner in the dorsal spinal cord. Local anesthetics, including ropivacaine, may represent a new approach for glial cell inhibition and, therefore, therapeutic strategies for neuropathic pain.</p

Pattern Recognition Analysis of Proton Nuclear Magnetic Resonance Spectra of Brain Tissue Extracts from Rats Anesthetized with Propofol or Isoflurane

BACKGROUND: General anesthesia is routinely used as a surgical procedure and its safety has been endorsed by clinical outcomes; however, its effects at the molecular level have not been elucidated. General anesthetics influence glucose metabolism in the brain. However, the effects of anesthetics on brain metabolites other than those related to glucose have not been well characterized. We used a pattern recognition analysis of proton nuclear magnetic resonance spectra to visualize the changes in holistic brain metabolic phenotypes in response to the widely used intravenous anesthetic propofol and the volatile anesthetic isoflurane. METHODOLOGY/PRINCIPAL FINDINGS: Rats were randomized into five groups (n = 7 each group). Propofol and isoflurane were administered to two groups each, for 2 or 6 h. The control group received no anesthesia. Brains were removed directly after anesthesia. Hydrophilic compounds were extracted from excised whole brains and measured by proton nuclear magnetic resonance spectroscopy. All spectral data were processed and analyzed by principal component analysis for comparison of the metabolite profiles. Data were visualized by plotting principal component (PC) scores. In the plots, each point represents an individual sample. The propofol and isoflurane groups were clustered separately on the plots, and this separation was especially pronounced when comparing the 6-h groups. The PC scores of the propofol group were clearly distinct from those of the control group, particularly in the 6-h group, whereas the difference in PC scores was more subtle in the isoflurane group and control groups. CONCLUSIONS/SIGNIFICANCE: The results of the present study showed that propofol and isoflurane exerted differential effects on holistic brain metabolism under anesthesia

Worse ECOG-PS Is Associated with Increased 30-Day Mortality among Adults Older than 90 Years Undergoing Non-Cardiac Surgery: A Single-Center Retrospective Study

journal articl

The Need for an Adult Intensive Care Unit Boot Camp for Residents and Fellows: A Cross-Sectional Survey among Intensive Care Unit Directors

journal articl