on Kyu Cho

Midazolam protects B35 neuroblastoma cells through Akt-phosphorylation in reactive oxygen species derived cellular injury

Background Soman, a potent irreversible acetylcholinesterase (AChE) inhibitor, induces delayed neuronal injury by reactive oxygen species (ROS). Midazolam is used in patients with pathologic effects of oxidative stresses such as infection, hemodynamic instability and hypoxia. We investigated whether midazolam protects the Central Nervous System (CNS) from soman intoxication. The present study was performed to determine whether midazolam protects B35 cells from ROS stress for the purpose of exploring an application of midazolam to soman intoxication. Methods Glucose oxidase (GOX) induced ROS stress was used in a B35 neuroblastoma cell model of ROS induced neuronal injury. To investigate the effect of midazolam on cell viability, LDH assays and fluorescence activated cell sorting (FACS) analysis was performed. Western blotting was used for evaluating whether Akt-phosphorylation is involved in cell-protective effects of midazolam. Results GOX derived ROS injury decreased cell viability about 1.6-2 times compared to control; midazolam treatment (5 and 10 µg/ml) dose-dependently increased cell viability during ROS injury. On western blots, Akt-phosphorylation was induced during pretreatment with midazolam; it was diminished during co-treatment with LY-294002, an inhibitor of Akt-phosphorylation. FACS analysis confirmed that the cell protective effect of midazolam is mediated by an anti-apoptotic effect. GOX-induced apoptosis was inhibited by midazolam and the finding was diminished by LY-294002. Conclusions Midazolam protects neuronal cells from GOX-induced ROS injury; this effect is mediated by an anti-apoptotic effect through Akt-phosphorylation. This shows that midazolam may be useful in soman intoxication.

The Effect of Thoracic Epidural Anesthesia on Pulmonary Shunt Fraction and Arterial Oxygenation During One-Lung Ventilation

OBJECTIVE To compare the effect of thoracic epidural local anesthetic, epidural opioid, and intravenous opioid on pulmonary shunt fraction, arterial oxygenation, and hemodynamic changes during one-lung ventilation (OLV) in patients undergoing thoracic surgery. DESIGN A prospective, randomized, double-blind study. SETTING A university hospital. PARTICIPANTS Thirty-nine patients undergoing OLV for pulmonary resection. INTERVENTIONS Patients were randomized into 1 of 3 groups: epidural bupivacaine (TEA-B group, n = 13), epidural sufentanil (TEA-S group, n = 13), or intravenous remifentanil (IV-R group, n = 13) during general anesthesia with propofol. A double-lumen tube was inserted, and mechanical ventilation with 100% oxygen was used in the lateral decubitus position. MEASUREMENTS AND MAIN RESULTS Hemodynamic variables and arterial and mixed venous blood gas analysis from the radial and pulmonary artery catheter were measured and shunt fraction was calculated during two-lung ventilation (TLV), 15, 30, and 60 minutes after the initiation of OLV, and 15 minutes after the reinstitution of TLV. Although mean arterial pressures 15 and 30 minutes after OLV in the IV-R group were significantly higher than the value in TEA-S group, cardiac output and pulmonary vascular resistance were maintained. Decreases in PaO(2), SaO(2), PvO(2), and SvO(2) and an increase in the shunt fraction after OLV were not different among groups and returned to baseline value after the resumption of TLV. CONCLUSIONS Thoracic epidural bupivacaine, epidural sufentanil, and intravenous remifentanil-combined general intravenous anesthesia have comparable effects on shunt fraction and arterial oxygenation during OLV in patients undergoing thoracic surgery.

Pleural effusion and atelectasis during continuous interscalene brachial plexus block -A case report-.

An interscalene brachial plexus block is an effective means of providing anesthesia-analgesia for shoulder surgery. However, it has a multitude of potential side effects such as phrenic nerve block. We report a case of a patient who developed atelectasis of the lung, and pleural effusion manifested as chest discomfort during a continuous interscalene brachial plexus block for postoperative analgesia.

A Randomized Comparison of Ropivacaine 0.1% and 0.2% for Continuous Interscalene Block After Shoulder Surgery

BACKGROUND:The optimal concentration of ropivacaine for continuous interscalene block after shoulder surgery is currently unknown. METHODS:Fifty-six patients received a perineural infusion of either ropivacaine 0.1% or 0.2% for 48 hours after shoulder surgery. We assessed pain scores as primary end points and supplemental analgesia, ropivacaine consumption, motor block, side effects, and patient satisfaction as secondary end points. RESULTS:Pain scores were not statistically different during the infusion periods; however, supplemental analgesia consumption was higher in the group receiving ropivacaine 0.1% during the first 24 hours (64% vs 28%, P = 0.022). Other secondary end points were statistically inconclusive. CONCLUSIONS:These results suggest that ropivacaine 0.2% provides more effective analgesia than ropivacaine 0.1% during the first 24 hours for continuous interscalene block after shoulder surgery.

Optimizing dose infusion of 0.125% bupivacaine for continuous femoral nerve block after total knee replacement

Background The optimal dose infusion of 0.125% bupivacaine via a femoral catheter after total knee replacement (TKR) has not been defined. This study examined various dose infusions of bupivacaine to determine the analgesic quality in patients receiving a continuous femoral nerve block (CFNB). Methods Patients were randomized to receive a single-injection femoral nerve block (SFNB) or CFNB performed with 20 ml of 0.125% bupivacaine, followed by a continuous infusion of 0.125% bupivacaine in four groups (n = 20 per group): 1) 0 ml/h (SFNB), 2) 2 ml/h, 3) 4 ml/h, and 4) 6 ml/h. The pain intensity at rest and on knee movement was assessed using a visual analog scale (VAS) for the first 2 postoperative days. The cumulative bolus use of IV patientcontrolled analgesia (PCA) with a morphine-ketorolac combination was evaluated. Results A lower cumulative bolus of IV PCA was noted in all CFNB groups compared to SFNB on postoperative days (PODs) 1 and 2, respectively (P < 0.05). Lower VAS scores at rest were observed in the 4 ml/h and 6 ml/h groups than in the SFNB group on PODs 1 and 2, respectively, but only on POD 2 in the 2 ml/h group (P < 0.05). Lower VAS scores on movement were noted in the 4 ml/h than the SFNB group on PODs 1 and 2, but only on POD 1 in 6 ml/h (P < 0.05). Conclusions The minimum effective infusion rate of 0.125% bupivacaine for CFNB after TKR appears to be 4 ml/h according to the VAS pain scores.

The effects of deep and light propofol anesthesia on stress response in patients undergoing open lung surgery: a randomized controlled trial.

Background This prospective, randomized controlled study was undertaken to compare stress hormone response to open thoracotomy for lung resection at different anesthetic depths, as determined by bispectral index (BIS) monitoring, in patients under propofol-remifentanil anesthesia. Methods Forty-eight adult patients scheduled for lung resection surgery using one-lung ventilation were randomly assigned to either a deep anesthesia group (BIS score of 40 ± 5, n = 24) or a light anesthesia group (BIS score of 60 ± 5, n = 24) by adjusting propofol infusion rates. Blood norepinephrine, epinephrine, adrenocorticotropic hormone, and cortisol levels were measured before the induction of anesthesia, at the end of surgery, and at 2 hours postoperatively. Blood glucose, hemodynamic, and oxygenation-ventilation variables, and postoperative outcomes were also measured. Results Norepinephrine and epinephrine levels remained unchanged over time in the deep group, but norepinephrine levels significantly increased in the light group at 2 h after surgery than at baseline (P = 0.007 and 0.004, respectively). Temporal changes in norepinephrine, but not in epinephrine, were significantly different between the two groups (P = 0.036). Plasma glucose levels in the light group increased with time and were significantly higher than in the deep group at the end of surgery (P = 0.002). Conclusions A deep level of anesthesia achieved using high propofol infusion rates during lung surgery provided lower perioperative norepinephrine and glucose responses than light level of anesthesia during the early postoperative period but failed to affect immediate postoperative outcomes.

Transient hemidiaphragmatic paresis after ultrasound-guided lateral sagittal infraclavicular block

As compared with medial approaches for the infraclavicular brachial plexus block, lateral approaches generally have no impact on the phrenic nerve or pulmonary function. A patient experienced transient hemidiaphragmatic paresis after ultrasound-guided lateral sagittal infraclavicular block for lower arm surgery. An accessory phrenic nerve, ie, an anatomical variation, may have been the mechanism of transient hemidiaphragmatic paresis in this patient.

Ultrasound-guided supraclavicular brachial plexus block in pediatric patients -A report of four cases-

Supraclavicular brachial plexus blocks are not common in pediatric patients due to the risk of pneumothorax. Ultrasonography is an important tool for identifying nerves during regional anesthesia. Directly visualizing the target nerves and monitoring the distribution of the local anesthetic are potentially significant. In addition, ultrasound monitoring helps avoid complications, such as inadvertent intravascular injection or pneumothorax. This paper reports four cases of pediatric patients who received ultrasound-guided supraclavicular brachial plexus block for upper limb surgery.

Comparison of vertical infraclavicular brachial plexus block with 0.5% levobupivacaine and 0.5% ropivacaine for upper limb surgery

BACKGROUND We performed a prospective, double blind study to compare the clinical effect of vertical infraclavicular brachial plexus block produced by 0.5% levobupivacaine and 0.5% ropivacaine for upper limb surgery. METHODS We included 60 patients receiving upper limb surgery under infraclavicular brachial plexus block. The infraclavicular brachial plexus block was performed via the vertical technique with 30 ml of 0.5% levobupivacaine or 0.5% ropivacaine. We observed which nerve type was stimulated and scored the sensory and motor block. The quality of block was assessed intraoperatively. The duration of sensory and motor block and complications were assessed. RESULTS There were no significant differences in frequencies of stimulated nerve type, evolution of sensory and motor block quality, or success of block. There were no significant difference in duration of sensory block, but duration of motor block was prolonged after 0.5% levobupivacaine. There were no complications. CONCLUSIONS Both 0.5% levobupivacaine and 0.5% ropivacaine had similar effects in the vertical infraclavicular brachial plexus block.

A comparison of posterior and medial cord stimulation for neurostimulation-guided vertical infraclavicular block: a randomized noninferiority clinical trial.

BACKGROUND:We investigated whether medial cord stimulation is inferior to posterior cord stimulation for vertical infraclavicular block with respect to block success. METHODS:Ninety-six patients scheduled for upper limb surgery were randomly elicited a medial or posterior cord response for infraclavicular block using 40 mL of 0.5% ropivacaine. We assessed block success (complete sensory block of the 5 nerves in the forearm at 50 minutes) as the primary end point and block procedure characteristics and adverse events as secondary end points. RESULTS:The block success rates did not differ significantly between medial and posterior cord stimulation (95.7% [44/46] vs 91.7% [44/48], 95% CI of difference, –7.4% to 15.6%), while the secondary end points were comparable in both groups. CONCLUSIONS:Needle manipulation to elicit medial cord response is noninferior to posterior cord response of block success during neurostimulation-guided vertical infraclavicular block.