Dexmedetomidine (DEX), a highly selective α2-adrenergic receptor agonist, is the newest agent introduced for sedation in intensive care unit (ICU). The sedation strategy for critically ill patients has stressed light sedation with daily awakening and assessment for neurologic, cognitive, and respiratory functions, since Society of Critical Care Medicine (SCCM) guidelines were presented in 2002. The traditional GABAergic agents, including benzodiazepines and propofol, have some limitations for safe sedatives in this setting, due to an unfavorable pharmacokinetic profile and to detrimental adverse effects (such as lorazepam associated propylene glycol intoxication and propofol infusion syndrome). DEX produces it's sedative, analgesic and cardiovascular effects through α2 receptors on the locus ceruleus (LC). Activities of LC, the tuberomammillary nucleus (TMN) are depressed and activity of the ventrolateral preoptic nucleus (VLPO) is increased during DEX sedation, which is similar in features to normal non-REM (NREM) sleep. At the same time, perifornical orexinergic activity is maintained, which might be associated with attention. This mechanism of action produces a normal sleep-like, cooperative sedation. The characteristic feature of sedation, together with a concomitant opioid sparing effect, may decrease the length of time spent on a ventilator, length of stay in ICU, and prevalence and duration of delirium, as the evidence shown from several comparative studies. In addition, DEX has an excellent safety profile. In conclusion, DEX is considered as a promising agent optimized for sedation in ICU.

MicroRNA (miRNA) pathways have been implicated in stem cell regulation. This study investigated the molecular effects of propofol on adipocyte stem cells (ASCs) by analyzing RNA expression arrays. Human ASCs were isolated by use of a liposuction procedure. ASCs were treated with saline, 50 µM propofol, or 100 µM propofol in culture media for 3 hours. After the isolation of total RNA, the expression of 76 miRNAs was evaluated with peptide nucleic acid-miRNA array analysis through denaturation and hybridization processes. Treatment with 50 µM propofol resulted in significant down-regulation of expression of 18 miRNAs and upregulation of expression of 25 miRNAs; 100 µM propofol resulted in significant downregulation of expression of 14 miRNAs and upregulation of expression of 29 miRNAs. The lowest expression was seen for miR-204, which was 0.07-fold with 50 µM propofol and 0.18-fold with 100 µM propofol. The highest expression was seen for miR-208b, which was 11.23-fold with 50 µM propofol and 11.20-fold with 100 µM propofol. Expression patterns of miRNAs were not significantly different between 50 µM and 100 µM propofol treatment. The results of this study suggest that propofol is involved in altering the miRNA expression level in human ASCs. Additional research is necessary to establish the functional effect of miRNA alteration by propofol.

BackgroundMany disinfectants have been used clinically in both single and combination applications, but there have been few studies on disinfective power according to sterilization sequence when using a combination of disinfectants. The purpose of this study was to evaluate the disinfective power of a combination of 70% isopropyl alcohol and 10% povidone-iodine (PVP-I) according to sterilization sequence.MethodsTwo hundred healthy volunteers were recruited. Subjects were disinfected with a combination of 70% isopropyl alcohol and 10% PVP-I on both forearms, in varying sequence. The AP group included disinfections on the left forearm with isopropyl alcohol first followed by 10% PVP-I, while the PA group included disinfections on the right forearm with same disinfectants in reverse order. Skin cultures were obtained using cotton swabs 3 min after application of each disinfectant, and then were inoculated on blood agar plates for bacterial culture. Cultures were incubated at 37℃ under aerobic conditions for 48 hours.ResultsThere was no significant difference in the number of positive cultures after the 1st disinfection (AP, 45; PA, 36, P = 0.262) or the 2nd disinfection (AP, 6; PA, 13, P = 0.157), suggesting that there is no relationship between disinfective power and the sequence of the disinfectants used. The number of positive cultures significantly decreased after the 2nd disinfection (P < 0.01), however.ConclusionsThere was no significant difference in disinfective power according to sterilization sequence with 70% isopropyl alcohol and 10% PVP-I in healthy volunteers. The combination of 70% isopropyl alcohol and 10% PVP-I was more effective than disinfection with a single agent regardless of sterilization sequence.

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Background: Lidocaine blocks sodium channels in nerve membranes, which inhibits sodium influx and prevents development of an action potential. For epidural anesthesia, we usually use lidocaine diluted in normal saline or distilled water. However, diluents containing sodium ions may affect lidocaine activity.Methods: Fifty patients, ASA physical status class I or II, scheduled for elective epidural anesthesia were randomly divided into two groups. For epidural anesthesia, we used 14 ml of 2% lidocaine solution made with 7 ml of 4% lidocaine plus an equivalent of distilled water (Group DW) or normal saline (Group NS). In the right lateral decubitus position, a 19 G Arrow catheter was inserted 3 cm in the cephalad direction in the L3-4 intervertebral space. In the supine position, 3 ml of 2% lidocaine was injected as a test dose, and the remaining 11 ml of lidocaine was injected 2 minutes later. We used a pinprick test for evaluation of sensory block levels and a Bromage grade for degrees of motor block every 2 minutes during the first 30 minutes.Results: Levels of sensory block were higher in Group DW than Group NS at 12, 14 and 30 minutes. The degree of motor block was also higher in Group DW at 12 and 14 minutes.Conclusions: Diluent containing sodium ions reduces sensory and motor block compared to sodium-free solution in epidural anesthesia.