The Efficacy and Safety of Dexmedetomidine for Procedural Sedation in Patients Receiving Local Anesthesia Outside the Intensive Care Unit: A Prospective, Double-Blind, Randomized Clinical Phase III Trial in Japan

Background: Few studies (in other countries than the US) have reported on the efficacy and safety of dexmedetomidine for sedation of patients undergoing surgical or medical procedures under local anesthesia without intubation outside the intensive care unit. We performed a randomized, double-blind study in Japan. Methods: Adult patients were randomly allocated to receive placebo, dexmedetomidine 0.5 μg/kg (DEX 0.5 group), or dexmedetomidine 1.0 μg/kg (DEX 1.0 group) over 10 min. Then, both dexmedetomidine groups received dexmedetomidine 0.2–0.7 μg/kg/h for maintaining an Observer’s Assessment of Alertness/Sedation Scale (OAA/S) score of ≤ 4; however, propofol was administered to rescue patients whose score exceeded this value. The primary endpoint was the percentage of patients who did not require rescue propofol to achieve and maintain an OAA/S score of ≤ 4. Results: In total, 162 patients were included in the placebo (n = 53), DEX 0.5 (n = 53), and DEX 1.0 (n = 56) groups. Propofol was not required in significantly more patients in the dexmedetomidine 0.5 and 1.0 μg/kg groups (52.8% and 57.1%, respectively) compared with the placebo group (1.9%) (P < 0.001 for both). Common adverse events were protocol-defined hypotension, respiratory depression and bradycardia. The incidence of bradycardia was significantly higher in the DEX 0.5 (26.4%) and DEX 1.0 (30.4%) groups than in the placebo group (9.4%) (P = 0.041 and P = 0.008, respectively). Conclusion: We concluded that a loading dose of 0.5 or 1.0 μg/kg dexmedetomidine followed by infusion at a rate of 0.2–0.7 μg/kg/h provided effective and welltolerated sedation in patients undergoing surgical or medical procedures under local anesthesia without intubation. Clinical trials.gov identifier: NCT0143893

Microsomal prostaglandin E synthase-1 is a critical factor of stroke-reperfusion injury

Although augmented prostaglandin E(2) (PGE(2)) synthesis and accumulation have been demonstrated in the lesion sites of rodent transient focal ischemia models, the role of PGE(2) in neuronal survival has been controversial, showing both protective and toxic effects. Here we demonstrate the induction of microsomal PGE synthase 1 (mPGES-1), an inducible terminal enzyme for PGE(2) synthesis, in neurons, microglia, and endothelial cells in the cerebral cortex after transient focal ischemia. In mPGES-1 knockout (KO) mice, in which the postischemic PGE(2) production in the cortex was completely absent, the infarction, edema, apoptotic cell death, and caspase-3 activation in the cortex after ischemia were all reduced compared with those in wild-type (WT) mice. Furthermore, the behavioral neurological dysfunctions observed after ischemia in WT mice were significantly ameliorated in KO mice. The ameliorated symptoms observed in KO mice after ischemia were reversed to almost the same severity as WT mice by intracerebroventricular injection of PGE(2) into KO mice. Our observations suggest that mPGES-1 may be a critical determinant of postischemic neurological dysfunctions and a valuable therapeutic target for treatment of human stroke