Dexmedetomidine ameliorates memory impairment in sleep-deprived mice.

The selective α2-adrenergic receptor agonist dexmedetomidine acts as an analgesic, sedative, and anesthetic adjuvant. The most common consequence of sleep deprivation is memory impairment. We investigated whether dexmedetomidine can counteract memory impairment caused by sleep deprivation and suppress the production of inflammatory factors. For inducing sleep deprivation, adult male mice were placed inside a water cage containing 15 platforms immersed in water up to 1 cm for 7 days. One day after sleep deprivation, dexmedetomidine at the respective dosage (5, 10, and 20 µg/kg) and α2-adrenoceptor antagonist atipamezole (250 µg/kg) were intraperitoneally injected into the mice, once per day for six days. The step-down avoidance task and the Morris water maze test were performed. Western blot analysis was performed to determine the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB), nuclear transcription factor-κB (NF-κB), inhibitor of κBα (IκBα), and ionized calcium binding adapter molecule I (Iba-1) in the hippocampus. Immunohistochemistry was performed for the determination of Ki-67 and glial fibrillary acidic protein (GFAP) expression in the hippocampal dentate gyrus. Dexmedetomidine ameliorated sleep deprivation-induced deterioration of short-term memory and spatial learning ability. Dexmedetomidine inhibited production of inflammatory mediators caused by sleep deprivation. Dexmedetomidine also prevented the decrease in BDNF, TrkB expression, and cell proliferation induced by sleep deprivation. Dexmedetomidine could be used to counteract the neuropathological effects of sleep deprivation.

Stroke Volume Variation and Stroke Volume Index Can Predict Fluid Responsiveness after Mini-Volume Challenge Test in Patients Undergoing Laparoscopic Cholecystectomy.

Background and Objectives: For using appropriate goal-directed fluid therapy during the surgical conditions of pneumoperitoneum in the reverse Trendelenburg position, we investigated the predictability of various hemodynamic parameters for fluid responsiveness by using a mini-volume challenge test. Materials and Methods: 42 adult patients scheduled for laparoscopic cholecystectomy were enrolled. After general anesthesia was induced, CO2 pneumoperitoneum was applied and the patient was placed in the reverse Trendelenburg position. The mini-volume challenge test was carried out with crystalloid 4 mL/kg over 10 min. Hemodynamic parameters, including stroke volume variation (SVV), cardiac index (CI), stroke volume index (SVI), mean arterial pressure (MAP), and heart rate (HR), were measured before and after the mini-volume challenge test. The positive fluid responsiveness was defined as an increase in stroke volume index ≥10% after the mini-volume challenge. For statistical analysis, a Shapiro-Wilk test was used to test the normality of the data. Continuous variables were compared using an unpaired t-test or the Mann-Whitney rank-sum test. Categorical data were compared using the chi-square test. A receiver operating characteristic curve analysis was used to assess the predictability of fluid responsiveness after the mini-volume challenge. Results: 31 patients were fluid responders. Compared with the MAP and HR, the SVV, CI, and SVI showed good predictability for fluid responsiveness after the mini-volume challenge test (area under the curve was 0.900, 0.833, and 0.909, respectively; all p-values were <0.0001). Conclusions: SVV and SVI effectively predicted fluid responsiveness after the mini-volume challenge test in patients placed under pneumoperitoneum and in the reverse Trendelenburg position.

Effect of Polydeoxyribonucleotide on Lipopolysaccharide and Sevoflurane-Induced Postoperative Cognitive dysfunction in Human Neuronal SH-SY5Y Cells.

PURPOSE: Postoperative cognitive dysfunction (POCD) is a complication of surgery characterized by acute cognitive dysfunction, memory impairment, and loss of attention. The effect of polydeoxyribonucleotide (PDRN) on the POCD environment induced by lipopolysaccharide (LPS) and sevoflurane exposure were investigated in human neuronal SH-SY5Y cells. METHODS: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and WST-8 assays were performed to determine cell viability. Cyclic adenosine-3,5'-monophosphate (cAMP), tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 concentrations were measured using enzyme-linked immunoassay (ELISA). Immunocytochemistry was performed for vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF), and western blotting for TNF-α, IL-1ß, IL-6, and cAMP response element-binding protein (CREB). RESULTS: Induction of the POCD environment reduced cell viability in the MTT and WST-8 assays. PDRN treatment reduced TNF-α, IL-1ß, and IL-6 expression in POCD conditions, and significantly increased cAMP concentrations and the p-CREB/CREB ratio. PDRN treatment activated adenosine A2A receptors and then increased the expression of VEGF and BDNF, which had been reduced by LPS and sevoflurane exposure. CONCLUSION: PDRN treatment showed a therapeutic effect on the LPS and sevoflurane-induced POCD environment. PDRN was shown to have an excellent therapeutic effect on POCD, not only by promoting rapid anti-inflammatory effects in damaged cells, but also by enhancing the expression of BDNF and VEGF.

Dexmedetomidine Ameliorates Sleep Deprivation-Induced Depressive Behaviors in Mice.

PURPOSE: Sleep deprivation induces depressive symptoms. Dexmedetomidine is a α2-adrenoreceptor agonist and this drug possesses sedative, anxiolytic, analgesic, and anesthetic-sparing effect. In this study, the action of dexmedetomidine on sleep deprivation-induced depressive behaviors was investigated using mice. METHODS: For the inducing of sleep deprivation, the mice were placed inside a water cage containing 15 platforms and filled with water up to 1 cm below the platform surface for 7 days. One day after sleep deprivation, dexmedetomidine at the respective dosage (0.5, 1, and 2 µg/kg) was intraperitoneally treated into the mice, one time per a day during 6 days. Then, forced swimming test and tail suspension test were conducted. Immunohistochemistry for tyrosine hydroxylase (TH), 5-hydroxytryptamine (5-HT; serotonin), tryptophan hydroxylase (TPH) and western blot for D1 dopamine receptor were also performed. RESULTS: Sleep deprivation increased the immobility latency in the forced swimming test and tail suspension test. The expressions of TPH, 5-HT, and D1 dopamine receptor were decreased, whereas, TH expression was increased by sleep deprivation. Dexmedetomidine decreased the immobility latency and increased the expressions of TPH, 5-HT, and D1 dopamine receptor, whereas, HT expression was decreased by dexmedetomidine treatment. CONCLUSION: In our results, dexmedetomidine alleviated sleep deprivation-induced depressive behaviors by increasing 5-HT synthesis and by decreasing dopamine production with up-regulation of D1 dopamine receptor.

Correlation between modified LEMON score and intubation difficulty in adult trauma patients undergoing emergency surgery.

Background: Prediction of difficult airway is critical in the airway management of trauma patients. A LEMON method which consists of following assessments; Look-Evaluate-Mallampati-Obstruction-Neck mobility is a fast and easy technique to evaluate patients' airways in the emergency situation. And a modified LEMON method, which excludes the Mallampati classification from the original LEMON score, also can be used clinically. We investigated the relationship between modified LEMON score and intubation difficulty score in adult trauma patients undergoing emergency surgery. Methods: We retrospectively reviewed electronic medical records of 114 adult trauma patients who underwent emergency surgery under general anesthesia. All patients' airways were evaluated according to the modified LEMON method before anesthesia induction and after tracheal intubation; the intubating doctor self-reported the intubation difficulty scale (IDS) score. A difficult intubation group was defined as patients who had IDS scores > 5. Results: The modified LEMON score was significantly correlated with the IDS score (P < 0.001). The difficult intubation group showed higher modified LEMON score than the non-difficult intubation group (3 [2-5] vs. 2 [1-3], respectively, P = 0.017). Limited neck mobility was the only independent predictor of intubation difficulty (odds ratio, 6.15; P = 0.002). Conclusion: The modified LEMON score is correlated with difficult intubation in adult trauma patients undergoing emergency surgery.

Pectoral nerve block (Pecs block) with sedation for breast conserving surgery without general anesthesia.

Most regional anesthesia in breast surgeries is performed as postoperative pain management under general anesthesia, and not as the primary anesthesia. Regional anesthesia has very few cardiovascular or pulmonary side-effects, as compared with general anesthesia. Pectoral nerve block is a relatively new technique, with fewer complications than other regional anesthesia. We performed Pecs I and Pec II block simultaneously as primary anesthesia under moderate sedation with dexmedetomidine for breast conserving surgery in a 49-year-old female patient with invasive ductal carcinoma. Block was uneventful and showed no complications. Thus, Pecs block with sedation could be an alternative to general anesthesia for breast surgeries.

Non-intubated thoracoscopic surgery for decortication of empyema under thoracic epidural anesthesia: a case report.

General anesthesia is the main strategy for almost all thoracic surgeries. However, a growing body of literature has reported successful cases of non-intubated thoracic surgery with regional anesthesia. This alternative strategy not only prevents complications related to general anesthesia, such as lung injury, incomplete re-expansion and intubation related problems, but also accords with trends of shorter hospital stay and lower overall costs. We experienced a successful case of non-intubated thoracoscopic decortication for a 68-year-old man who was diagnosed as empyema while the patient kept spontaneously breathing with moderate sedation under thoracic epidural anesthesia. The patient showed a fast recovery without concerns of general anesthesia related complications and effective postoperative analgesia through thoracic epidural patient-controlled analgesia device. This is the first report of non-intubated thoracoscopic surgery under thoracic epidural anesthesia in Korea, and we expect that various well designed prospective studies will warrant the improvement of outcomes in non-intubated thoracoscopic surgery.

Postnatal Treadmill Exercise Alleviates Prenatal Stress-Induced Anxiety in Offspring Rats by Enhancing Cell Proliferation Through 5-Hydroxytryptamine 1A Receptor Activation.

PURPOSE: Stress during pregnancy is a risk factor for the development of anxiety-related disorders in offspring later in life. The effects of treadmill exercise on anxiety-like behaviors and hippocampal cell proliferation were investigated using rats exposed to prenatal stress. METHODS: Exposure of pregnant rats to a hunting dog in an enclosed room was used to induce stress. Anxiety-like behaviors of offspring were evaluated using the elevated plus maze test. Immunohistochemistry for the detection of 5-bromo-2ʹ- deoxyuridine and doublecortin (DCX) in the hippocampal dentate gyrus and 5-hydroxytryptamine 1A receptors (5-HT1A) in the dorsal raphe was conducted. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) levels in the hippocampus were evaluated by western blot analysis. RESULTS: Offspring of maternal rats exposed to stress during pregnancy showed anxiety-like behaviors. Offspring also showed reduced expression of BDNF, TrkB, and DCX in the dentate gyrus, decreased cell proliferation in the hippocampus, and reduced 5-HT1A expression in the dorsal raphe. Postnatal treadmill exercise by offspring, but not maternal exercise during pregnancy, enhanced cell proliferation and expression of these proteins. CONCLUSIONS: Postnatal treadmill exercise ameliorated anxiety-like behaviors in offspring of stressed pregnant rats, and the alleviating effect of exercise on these behaviors is hypothesized to result from enhancement of cell proliferation through 5-HT1A activation in offspring rats.

Time course of end-tidal desflurane concentration during delivery and elimination according to the type and location of filters in a semi-closed circuit system.

BACKGROUND: The aim of this study was to determine whether the end-tidal concentration of desflurane would be affected by a breathing circuit system filter attached at two different positions in anesthetic breathing circuit systems. METHODS: An artificial lung was ventilated under five different conditions. The first group was without any filter or desflurane (n = 5, sham), the second was with desflurane but without any filter (n = 10, control), the third group had a bacterial filter on the expiratory limb (n = 10), and the fourth and fifth groups had a viral/bacterial filter added on the expiratory limb (n = 10) or at the Y-piece of the breathing circuit (n = 10), respectively. In all groups except the sham, administration of 10% desflurane was performed for 5 minutes and then stopped for 5 minutes. RESULTS: The mean (SD) end-tidal concentration of desflurane for the groups described above peaked at 0 (0), 9.8 (0.1), 9.8 (0.1), 8.5 (0.1), and 6.7% (0.1) (P < 0.001), respectively. There was no difference in the desflurane concentrations and the expired tidal volume over time between the control and bacterial group, but there was a significant difference between the control and the fourth and fifth groups (P < 0.001). CONCLUSIONS: Filters can affect the expiratory desflurane concentration during anesthesia.

The comparison of monitored anesthesia care with dexmedetomidine and spinal anesthesia during varicose vein surgery.

PURPOSE: The purpose of this study was to investigate the effectiveness and safety of monitored anesthesia care (MAC) using dexmedetomidine for its sedative and analgesic effect during varicose vein surgery. METHODS: Forty-two patients, who underwent varicose vein surgery, were divided into the MAC group (n = 20) or the spinal anesthesia group (n = 22) for randomized clinical trial. In the MAC group, dexmedetomidine was administered by a loading dose of 1 µg/kg for 10 minutes, followed by a maintenance infusion of 0.2-1.0 µg/kg/hr. Ketamine was used for intermittent injection. In the spinal anesthesia group, midazolam was used for sedation. Intraoperative vital signs, the number of adverse events, and the satisfaction of patients and surgeons concerning the anesthetic condition were compared between the two groups. RESULTS: Systolic blood pressure was intraoperatively significantly different over time between the two groups. The groups had statistical differences in the change in heart rate with regard to time. In the postanesthetic care unit, patients and surgeons in the MAC group had a lower satisfaction score, compared to patients and surgeons in the spinal anesthesia group. However, in the recovery period, patients had a positive perception concerning MAC anesthesia. In addition, without significant adverse events, the MAC group had a shorter time to possible ambulation, which indicated an early recovery. CONCLUSION: We believe that MAC using dexmedetomidine in combination with ketamine may be an alternative anesthetic technique for varicose vein surgery with regard to a patient's preference and medical condition.