MicroRNA-323-5p Involved in Dexmedetomidine Preconditioning Impart Neuroprotection.

Background and Objectives: Cerebral ischemia is one of the major preoperative complications. Dexmedetomidine is a well-known sedative-hypnotic agent that has potential organ-protective effects. We examine the miRNAs associated with preconditioning effects of dexmedetomidine in cerebral ischemia. Materials and Methods: Transient infarcts were induced in mice via reperfusion after temporary occlusion of one side of the middle cerebral artery. A subset of these mice was exposed to dexmedetomidine prior to cerebral infarction and miRNA profiling of the whole brain was performed. We administered dexmedetomidine and miRNA-323-5p mimic/inhibitor to oxygen-glucose deprivation/reoxygenation astrocytes. Additionally, we administered miR-323-5p mimic and inhibitor to mice via intracerebroventricular injection 2 h prior to induction of middle cerebral artery occlusion. Results: The infarct volume was significantly lower in the dexmedetomidine-preconditioned mice. Analysis of brain samples revealed an increased expression of five miRNAs and decreased expression of three miRNAs in the dexmedetomidine-pretreated group. The viability of cells significantly increased and expression of miR-323-5p was attenuated in the dexmedetomidine-treated oxygen-glucose deprivation/reoxygenation groups. Transfection with anti-miR-323-5p contributed to increased astrocyte viability. When miRNA-323-5p was injected intraventricularly, infarct volume was significantly reduced when preconditioned with the miR-323-5p inhibitor compared with mimic and negative control. Conclusions: Dexmedetomidine has a protective effect against transient neuronal ischemia-reperfusion injury and eight specific miRNAs were profiled. Also, miRNA-323-5p downregulation has a cell protective effect under ischemic conditions both in vivo and in vitro. Our findings suggest the potential of the miR-323-5p inhibitor as a therapeutic agent against cerebral infarction.

Development of pre-procedure virtual simulation for challenging interventional procedures: an experimental study with clinical application.

Background: Most pain management techniques for challenging procedures are still performed under the guidance of the C-arm fluoroscope although it is sometimes difficult for even experienced clinicians to understand the modified three-dimensional anatomy as a two-dimensional X-ray image. To overcome these difficulties, the development of a virtual simulator may be helpful. Therefore, in this study, the authors developed a virtual simulator and presented its clinical application cases. Methods: We developed a computer program to simulate the actual environment of the procedure. Computed tomography (CT) Digital Imaging and Communications in Medicine (DICOM) data were used for the simulations. Virtual needle placement was simulated at the most appropriate position for a successful block. Using a virtual C-arm, the authors searched for the position of the C-arm at which the needle was visualized as a point. The positional relationships between the anatomy of the patient and the needle were identified. Results: For the simulations, the CT DICOM data of patients who visited the outpatient clinic was used. When the patients revisited the clinic, images similar to the simulated images were obtained by manipulating the C-arm. Transforaminal epidural injection, which was difficult to perform due to severe spinal deformity, and the challenging procedures of the superior hypogastric plexus block and Gasserian ganglion block, were successfully performed with the help of the simulation. Conclusions: We created a pre-procedural virtual simulation and demonstrated its successful application in patients who are expected to undergo challenging procedures.

A Comparison of Anesthetic Quality between Single and Septum-based Double Injection for Ultrasound-Guided Costoclavicular Block: A Randomized Controlled Trial.

BACKGROUND: In a costoclavicular (CC) approach of an ultrasound (US)-guided infraclavicular brachial plexus block (BPB), a septum between the lateral and the medial/posterior cords can result in an incomplete block. We hypothesized that double injections in each compartment between the septum would result in a higher success rate of BPB than a single injection in the center of the CC space. OBJECTIVES: This study was conducted to confirm the superiority of block quality achieved by septum-based double injections (experimental group; group E) over single injection in the center of the CC space (control group; group C). STUDY DESIGN: A randomized, controlled trialSETTING: Department of Anesthesiology and Pain Medicine, Korea University College of Medicine, Anam Hospital. METHODS: Sixty-eight patients who underwent upper extremity surgery randomly received a single (SI group, n = 34) or a septum-based double injection (DI group, n = 34) using the CC approach. Ten milliliters of 2% lidocaine, 10 mL of 0.75% ropivacaine, and 5 mL of normal saline were used for BPB in each group (total 25 mL). Sensory-motor blockade of the ipsilateral median, radial, ulnar, and musculocutaneous nerves was assessed by a blinded observer at 5-minute intervals for 30 minutes immediately after local anesthesia administration. The assessed variables were the success rate, the rate of all 4 nerves blockade, and onset time. RESULTS: Thirty minutes after the block, the success rate was significantly higher in the DI group than in the SI group (64.7% in the SI group vs 91.2% in the DI group, P = 0.009), and the rate of all 4 nerves blockade also significantly increased in the DI group compared to the SI group (44.1% in the SI group vs 91.2% in the DI group, P = 0). The onset time was significantly shortened in the DI group compared with the SI group (26.3 ± 5.6 min in the SI group vs 21.3 ± 6.2 min in the DI group, P = 0.010). LIMITATIONS: We considered that the location of the septum was always between the lateral cord superficially and the medial/posterior cords below it. In some patients in whom the septum was not visible, a superficial lateral cord was injected first, and then deep medial and posterior cords were injected, assuming that the 2 compartments were divided by the septum. CONCLUSIONS: Compared with the SI, the septum-based DI of CC approach increased the success rate and the rate of all 4 nerves blockade and shortened the onset time.