Enhancing Structural Health Monitoring with Acoustic Emission Sensors: A Case Study on Composites under Cyclic Loading.

This study conducts an in-depth analysis of the failure behavior of woven GFRP under cyclic loading, leveraging AE sensors for monitoring damage progression. Utilizing destructive testing and AE methods, we observed the GFRP's response to varied stress conditions. Key findings include identifying distinct failure modes of GFRP and the effectiveness of AE sensors in detecting broadband frequency signals indicative of crack initiation and growth. Notably, the Felicity effect was observed in AE signal patterns, marking a significant characteristic of composite materials. This study introduces the Ibe-value, based on statistical parameters, to effectively track crack development from inception to growth. The Ibe-values potential for assessing structural integrity in composite materials is highlighted, with a particular focus on its variation with propagation distance and frequency-dependent attenuation. Our research reveals challenges in measuring different damage modes across frequency ranges and distances. The effectiveness of Ibe-values, combined with the challenges of propagation distance, underscores the need for further investigation. Future research aims to refine assessment metrics and improve crack evaluation methods in composite materials, contributing to the field's advancement.

Assessment of Preoperative Anxiety and Influencing Factors in Patients Undergoing Elective Surgery: An Observational Cross-Sectional Study.

Background and Objectives: Preoperative anxiety is a common emotional response before elective surgery that influences postoperative outcomes and can increase analgesic requirements. However, clinicians frequently overlook these concerns. This study aimed to quantify preoperative anxiety and evaluate its association with patient-related factors. Materials and Methods: Anxiety levels were evaluated in adult patients awaiting elective surgery using the Korean-translated version of the Amsterdam Preoperative Anxiety and Information Scale (APAIS) and the State-Trait Anxiety Inventory-Korean YZ form (STAI-KYZ). The patients were also surveyed regarding the subjective causes of preoperative anxiety. Results: The study found that a total of 55 adult patients had a well-balanced subject distribution. Both questionnaires showed high internal consistency (Cronbach's alpha values of 0.85 and 0.93). Significant correlations were observed in situational anxiety scores from the questionnaires, indicating differences between groups with high trait anxiety and those with normal anxiety levels (p < 0.05). Notably, female sex was the only patient-related factor that significantly affected the anxiety scores (p < 0.05). Furthermore, when considering additional patient factors stratified by sex, it became evident that younger females and females with prior general anesthesia experience displayed higher anxiety levels than their male counterparts. The most commonly reported subjective concern related to anesthesia was the fear of not regaining consciousness, followed by concerns about postoperative pain, intraoperative emergence, and other issues. Conclusions: This study confirms that being female is a significant risk factor for preoperative anxiety. Therefore, it is necessary to provide enhanced preoperative anxiolytic therapies, including preoperative patient education and other interventions, to individuals undergoing surgical procedures.

Predictive factors for conversion from conservatively to surgically treatment osteoporotic thoracolumbar compression fractures based on sagittal parameters and magnetic resonance imaging features.

PURPOSE: To investigate the relationship between sagittal plane characteristics of the spinal column and conservative treatment failure in acute osteoporotic spinal fractures (OSFs). METHODS: As a retrospective study of single-institute data, thoracolumbar OSF patients with similar propensities in terms of location of fractures and results of bone mineral density were analyzed. Among them, 43 patients (group I) who needed reconstructive surgical interventions and 39 patients (group II) who obtained successful treatment through conservative care were included. General demographic data, radiographic features of fractures, and magnetic resonance imaging (MRI) features of fractures were analyzed. To investigate the relationship between global sagittal alignment of the spine and occurrence of delayed complication following OSFs, radiological sagittal parameters were analyzed. RESULTS: The number of cases requiring reconstructive surgery was significantly higher when the index vertebra showed diffuse or mid-portion bone marrow changes in MRI. In terms of sagittal parameters, pelvic incidence (group I 59.1° ± 11.9°, group II 54.6° ± 9.8°) and thoracolumbar angle (group I 26.5° ± 14.1°, group II 17.4° ± 11.2°) were significantly higher in group I. Logistic regression analysis showed that higher pelvic incidence (OR 1.09, 95% CI 1.01-1.18, p value < 0.05) and higher thoracolumbar angle (OR 1.09, 95% CI 1.02-1.17, p value < 0.05) were significant risk factors for delayed complications requiring reconstructive surgery following OSFs. CONCLUSION: Delayed complications requiring reconstructive surgery following OSFs are related to sagittal plane parameters of the spine such as high pelvic incidences, in addition to previously known radiographic characteristics of fractures.

Unexpected Tension Pneumothorax Developed during Anesthetic Induction Aggravated by Positive Pressure Ventilation: A Case Report.

Background and Objectives: Tension pneumothorax is a life-threatening emergency condition that requires immediate diagnosis and intervention. However, due to the non-specific symptoms and the rarity of its occurrence during surgery, anesthesiologists encounter difficulties in promptly diagnosing tension pneumothorax when it arises intraoperatively. Diagnosing tension pneumothorax can become even more challenging in unexpected situations in patients with normal preoperative evaluation for general anesthesia. Materials and Methods, Results: We report the case of a 66-year-old woman who underwent general anesthesia for oblique lateral interbody fusion surgery of her lumbar spine. Though she did not have any respiratory symptoms prior to the induction of anesthesia, auscultation following endotracheal intubation indicated decreased breathing sound in the left hemithorax of the chest. Subsequently, her vital signs showed tachycardia, hypotension, and hypoxemia, and the ventilator indicated a gradual increase in the airway pressure. We verified the proper depth of the endotracheal tube to exclude one-lung ventilation, and, in the meantime, learned that there had been unsuccessful attempts at left subclavian venous catheterization by the surgical department on the previous day. Tension pneumothorax was diagnosed through portable chest radiography in the operating room, and needle thoracostomy and chest tube insertion were performed immediately, which in turn stabilized her vital signs and airway pressure. The surgery was uneventful, and the chest tube was removed one week later after evaluation by the cardiothoracic department. The patient was discharged from hospital on postoperative day 14 without known complications. Conclusions: Anesthesiologists should be aware of the conditions and risk factors that may cause tension pneumothorax and remain vigilant for signs of its development throughout surgery, even for patients who show normal preoperative assessments. An undetected small pneumothorax without any symptoms can progress to tension pneumothorax through positive pressure ventilation during general anesthesia, posing a life-threatening situation. If a tension pneumothorax is highly suspected through clinical assessments, its prompt differentiation and timely diagnosis are crucial, allowing for rapid intervention to stabilize vital signs.

Asymptomatic Type 2 Perioperative Myocardial Infarction Detected before Anesthetic Induction in a Patient Undergoing Non-Cardiac Surgery-A Case Report.

Background: Perioperative myocardial infarction (PMI) is a life-threatening complication in major non-cardiac surgeries (NCS) and constitutes the most common cause of postoperative morbidity and mortality. A PMI that is associated with prolonged oxygen supply-demand imbalance and its etiology is defined as a type 2 MI. Asymptomatic myocardial ischemia can occur in patients with stable coronary artery disease (CAD), especially those with comorbidities such as diabetes mellitus (DM), hypertension, or, in some cases, without any risk factors. Case: We report a case of asymptomatic PMI in a 76-year-old patient with underlying hypertension and DM without a previous history of CAD. During the induction of anesthesia, abnormal electrocardiography was discovered, and the surgery was postponed after further studies revealed almost completely occluded three-vessel CAD and type 2 PMI. Conclusions: Anesthesiologists should closely monitor and evaluate the associated cardiovascular risk, including cardiac biomarkers of each patient before surgery, to minimize the possibility of PMI.

Detection of Prosthetic Loosening in Hip and Knee Arthroplasty Using Machine Learning: A Systematic Review and Meta-Analysis.

Background: prosthetic loosening after hip and knee arthroplasty is one of the most common causes of joint arthroplasty failure and revision surgery. Diagnosis of prosthetic loosening is a difficult problem and, in many cases, loosening is not clearly diagnosed until accurately confirmed during surgery. The purpose of this study is to conduct a systematic review and meta-analysis to demonstrate the analysis and performance of machine learning in diagnosing prosthetic loosening after total hip arthroplasty (THA) and total knee arthroplasty (TKA). Materials and Methods: three comprehensive databases, including MEDLINE, EMBASE, and the Cochrane Library, were searched for studies that evaluated the detection accuracy of loosening around arthroplasty implants using machine learning. Data extraction, risk of bias assessment, and meta-analysis were performed. Results: five studies were included in the meta-analysis. All studies were retrospective studies. In total, data from 2013 patients with 3236 images were assessed; these data involved 2442 cases (75.5%) with THAs and 794 cases (24.5%) with TKAs. The most common and best-performing machine learning algorithm was DenseNet. In one study, a novel stacking approach using a random forest showed similar performance to DenseNet. The pooled sensitivity across studies was 0.92 (95% CI 0.84-0.97), the pooled specificity was 0.95 (95% CI 0.93-0.96), and the pooled diagnostic odds ratio was 194.09 (95% CI 61.60-611.57). The I2 statistics for sensitivity and specificity were 96% and 62%, respectively, showing that there was significant heterogeneity. The summary receiver operating characteristics curve indicated the sensitivity and specificity, as did the prediction regions, with an AUC of 0.9853. Conclusions: the performance of machine learning using plain radiography showed promising results with good accuracy, sensitivity, and specificity in the detection of loosening around THAs and TKAs. Machine learning can be incorporated into prosthetic loosening screening programs.

Smooth Emergence from General Anesthesia after Deep Extubation in a Pediatric Patient Diagnosed with Catecholaminergic Polymorphic Ventricular Tachycardia: A Case Report.

Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare genetic disorder where catecholamine causes bidirectional ventricular tachycardia, potentially leading to cardiac arrest. In patients undergoing surgery, sympathetic responses can be triggered in situations associated with surgical stimulations as well as high anxiety before the surgery, anesthetic maneuvers such as endotracheal intubation and extubation, and postoperative pain. Therefore, planning for surgery demands meticulous attention to anesthesia during the perioperative period in order to prevent potentially life-threatening arrhythmias. Case: We discuss a case of an 11-year-old male pediatric patient with known CPVT who required elective strabismus surgery for exotropia involving both eyes. After thorough planning of general anesthesia to minimize catecholamine response, sufficient anesthesia and analgesia were achieved to blunt the stressful response during intubation and maintained throughout the surgical procedure. Complete emergence was achieved after deep extubation, and the patient did not complain of pain or postoperative nausea and vomiting. Conclusions: Anesthesiologists should not only be able to plan and manage the catecholamine response during surgery but also anticipate and be prepared for situations that may lead to arrhythmias before and after the procedure. In certain cases, deep extubation can be beneficial as it reduces hemodynamic changes during the extubation process.

Benzyl Isothiocyanate Attenuates Inflammasome Activation in Pseudomonas aeruginosa LPS-Stimulated THP-1 Cells and Exerts Regulation through the MAPKs/NF-κB Pathway.

Inflammasomes are a group of intracellular multiprotein platforms that play important roles in immune systems. Benzyl isothiocyanate (BITC) is a constituent of cruciferous plants and has been confirmed to exhibit various biological activities. The modulatory effects of BITC on inflammasome-mediated interleukin (IL)-1ß expression and its regulatory mechanisms in Pseudomonas aeruginosa (P. aeruginosa) LPS/ATP-stimulated THP-1 cells was investigated. Monocytic THP-1 cells were treated with phorbol myristate acetate (PMA) to induce differentiation into macrophages. Enzyme-linked immunosorbent assays (ELISA) were performed to measure the levels of IL-1ß produced in P. aeruginosa LPS/ATP-exposed THP-1 cells. Western blotting was performed to examine the BITC modulatory mechanisms in inflammasome-mediated signaling pathways. BITC inhibited IL-1ß production in P. aeruginosa LPS/ATP-induced THP-1 cells. BITC also inhibited activation of leucine-rich repeat protein-3 (NLRP3) and caspase-1 in P. aeruginosa LPS/ATP-induced THP-1 cells. Furthermore, we show that mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) activation in P. aeruginosa LPS was attenuated by BITC. These BITC-mediated modulatory effects on IL-1ß production may have therapeutic potential for inflammasome-mediated disorders such as a nasal polyp.

Etiology of distinct membrane excitability in pre- and posthearing auditory neurons relies on activity of Cl- channel TMEM16A.

The developmental rehearsal for the debut of hearing is marked by massive changes in the membrane properties of hair cells (HCs) and spiral ganglion neurons (SGNs). Whereas the underlying mechanisms for the developing HC transition to mature stage are understood in detail, the maturation of SGNs from hyperexcitable prehearing to quiescent posthearing neurons with broad dynamic range is unknown. Here, we demonstrated using pharmacological approaches, caged-Ca(2+) photolysis, and gramicidin patch recordings that the prehearing SGN uses Ca(2+)-activated Cl(-) conductance to depolarize the resting membrane potential and to prime the neurons in a hyperexcitable state. Immunostaining of the cochlea preparation revealed the identity and expression of the Ca(2+)-activated Cl(-) channel transmembrane member 16A (TMEM16A) in SGNs. Moreover, null deletion of TMEM16A reduced the Ca(2+)-activated Cl(-) currents and action potential firing in SGNs. To determine whether Cl(-) ions and TMEM16A are involved in the transition between pre- and posthearing features of SGNs we measured the intracellular Cl(-) concentration [Cl(-)]i in SGNs. Surprisingly, [Cl(-)]i in SGNs from prehearing mice was ∼90 mM, which was significantly higher than posthearing neurons, ∼20 mM, demonstrating discernible altered roles of Cl(-) channels in the developing neuron. The switch in [Cl(-)]i stems from delayed expression of the development of intracellular Cl(-) regulating mechanisms. Because the Cl(-) channel is the only active ion-selective conductance with a reversal potential that lies within the dynamic range of SGN action potentials, developmental alteration of [Cl(-)]i, and hence the equilibrium potential for Cl(-) (ECl), transforms pre- to posthearing phenotype.

Genetic, cellular, and functional evidence for Ca2+ inflow through Cav1.2 and Cav1.3 channels in murine spiral ganglion neurons.

Spiral ganglion neurons (SGNs) of the eighth nerve serve as the bridge between hair cells and the cochlear nucleus. Hair cells use Cav1.3 as the primary channel for Ca(2+) inflow to mediate transmitter release. In contrast, SGNs are equipped with multiple Ca(2+) channels to mediate Ca(2+)-dependent functions. We examined directly the role of Cav1.3 channels in SGNs using Cav1.3-deficient mice (Cav1.3(-/-)). We revealed a surprising finding that SGNs functionally express the cardiac-specific Cav1.2, as well as neuronal Cav1.3 channels. We show that evoked action potentials recorded from SGNs show a significant decrease in the frequency of firing in Cav1.3(-/-) mice compared with wild-type (Cav1.3(+/+)) littermates. Although Cav1.3 is the designated L-type channel in neurons, whole-cell currents recorded in isolated SGNs from Cav1.3(-/-) mice showed a surprising remnant current with sensitivity toward the dihydropyridine (DHP) agonist and antagonist, and a depolarization shift in the voltage-dependent activation compared with that in the Cav1.3(+/+) mice. Indeed, direct measurement of the elementary properties of Ca(2+) channels, in Cav1.3(+/+) neurons, confirmed the existence of two DHP-sensitive single-channel currents, with distinct open probabilities and conductances. We demonstrate that the DHP-sensitive current in Cav1.3(-/-) mice is derived from Cav1.2 channel activity, providing for the first time, to our knowledge, functional data for the expression of Cav1.2 currents in neurons. Finally, using shRNA gene knockdown methodology, and histological analyses of SGNs from Cav1.2(+/-) and Cav1.3(+/-) mice, we were able to establish the differential roles of Cav1.2 and Cav1.3 in SGNs.

Functional significance of K+ channel ß-subunit KCNE3 in auditory neurons.

The KCNE3 ß-subunit interacts with and regulates the voltage-dependent gating, kinetics, and pharmacology of a variety of Kv channels in neurons. Because a single neuron may express multiple KCNE3 partners, it is impossible to predict the overall functional relevance of the single transmembrane domain peptide on the pore-forming K(+) channel subunits with which it associates. In the inner ear, the role of KCNE3 is undefined, despite its association with Meniere disease and tinnitus. To gain insights on the functional significance of KCNE3 in auditory neurons, we examined the properties of spiral ganglion neurons (SGNs) in Kcne3 null mutant neurons relative to their age-matched controls. We demonstrate that null deletion of Kcne3 abolishes characteristic wide variations in the resting membrane potentials of SGNs and yields age-dependent alterations in action potential and firing properties of neurons along the contour of the cochlear axis, in comparison with age-matched wild-type neurons. The properties of basal SGNs were markedly altered in Kcne3(-/-) mice compared with the wild-type controls; these include reduced action potential latency, amplitude, and increased firing frequency. Analyses of the underlying conductance demonstrate that null mutation of Kcne3 results in enhanced outward K(+) currents, which is sufficient to explain the ensuing membrane potential changes. Additionally, we have demonstrated that KCNE3 may regulate the activity of Kv4.2 channels in SGNs. Finally, there were developmentally mediated compensatory changes that occurred such that, by 8 weeks after birth, the electrical properties of the null mutant neurons were virtually indistinguishable from the wild-type neurons, suggesting that ion channel remodeling in auditory neurons progresses beyond hearing onset.

Precise toxigenic ablation of intermediate cells abolishes the "battery" of the cochlear duct.

The extracellular potential of excitable and nonexcitable cells with respect to ground is ∼0 mV. One of the known exceptions in mammals is the cochlear duct, where the potential is ∼80-100 mV, called the endocochlear potential (EP). The EP serves as the "battery" for transduction of sound, contributing toward the sensitivity of the auditory system. The stria vascularis (StV) of the cochlear duct is the station where the EP is generated, but the cell-specific roles in the StV are ill defined. Using the intermediate cell (IC)-specific tyrosinase promoter, under the control of diphtheria toxin (DT), we eliminated and/or halted differentiation of neural crest melanocytes after migration to the StV. The ensuing adult transgenic mice are profoundly deaf. Additionally, the EP was abolished. Expression of melanocyte early marker and Kir4.1 in ICs precedes the onset of pigment synthesis. Activation of DT leads to loss of ICs. Finally, in accord with the distinct embryology of retinal pigmented cells, transgenic mice with toxigenic ablation of neural crest-derived melanocytes have intact visual responses. We assert that the tyrosinase promoter is the distinct target for genetic manipulation of IC-specific genes.

Enhancing Reliability and Safety in Industrial Applications: Assessing the Applicability of Energy b-Value to Composites.

This study investigates the fracture behavior of glass fiber-reinforced plastic (GFRP) under various loading conditions using acoustic emission (AE) testing. Using fracture tests and time series analysis of AE signals, parameters such as b-value, improved b-value (Ib-value), and energy b-value (be-value) were examined to understand crack initiation, growth, and structural failure. The stress-strain curve revealed distinct responses during tensile and step loading, and time series analysis highlighted variations in amplitude, AE energy, and Kaiser and Felicity effects. Under tensile loading, the Ib-value exhibited a linear decrease, while step loading introduced complexities, including the Felicity effect. The be-value, incorporating energy considerations, fluctuated, providing insights into micro-cracks and macro-cracks. Statistical analysis demonstrated a consistent decrease in the be-value, emphasizing its potential for long-term monitoring. This study provides a comprehensive technique for assessing composite material fracture behavior, enhancing understanding for critical applications in hydrogen storage vessels and pressure pipes as well as advancing reliability and safety in industrial sectors.

Dorsal Scapholunate Ligament Complex Reconstruction Using Suture Tape-Augmented Autologous Free Tendon Graft for Chronic Scapholunate Dissociation.

Background: The treatment of chronic scapholunate dissociation (SLD) can be challenging due to several factors such as poor quality of ligament, malalignment of the carpus, limited surgical options, and risk of recurrent instability. Various surgical techniques have been developed, but there is ongoing debate regarding the optimal surgical technique. This study aimed to report the clinical and radiological outcomes after dorsal scapholunate (SL) ligament complex reconstruction using suture tape-augmented autologous tendon graft. Methods: The study included patients with Garcia-Elias stage 3-4 chronic SLD, SL advanced collapse (SLAC) stage 1, and a follow-up period exceeding 1 year. Pre- and postoperative SL gap, SL angle (SLA), radiolunate angle (RLA), and dorsal scaphoid translation (DST) were measured, and wrist active range of motion, Modified Mayo Wrist Score (MMWS), and visual analog scale (VAS) were evaluated. Results: Nine patients were included in this study with a mean follow-up period of 17 months (range, 15-31 months). All patients were male, with a mean age of 49 years (range, 30-62 years). Eight patients were classified as Garcia-Elias stage 4, while one was classified as SLAC 1. The median (range) of preoperative, immediate postoperative, and final follow-up measurements for SL gap, SLA, RLA, and DST were 5.4 mm (4.5-5.9), 2.1 mm (1.8-2.5), and 2.5 mm (2.0-2.8) (p = 0.008); 76° (69°-88°), 50° (32°-56°), and 54° (50°-64°) (p = 0.008); 22° (11.5°-33°), 2.8° (0.5°-3.8°), and 3.8° (2.2°-5.6°) (p = 0.008); and 2.8 mm (2.0-3.4), 0.8 mm (0.1-1.2), and 1.0 mm (0.1-2.0) (p = 0.008), respectively. Immediately after surgery, all radiological measurements showed significant improvement, which persisted up to 15 months postoperatively. The preoperative and final follow-up measurements of active flexion, extension, radial deviation, and ulnar deviation of the wrist showed significant improvement. The median preoperative and final follow-up values of MMWS were 51.1 (range, 40-60) and 88.3 (range, 85-95) (p = 0.007), respectively, and those of VAS were 7 (range, 6-8) and 2 (range, 1-3) (p = 0.007), respectively. Conclusions: Dorsal SL ligament complex reconstruction using suture tape-augmented autologous free tendon graft could be regarded as a feasible and straightforward technique for addressing irreparable chronic SLD.

Guidewire insertion into the vertebral vein during right internal jugular vein central venous catheterization -A rare case report.

BACKGROUND: Internal jugular veins are the most frequently accessed site for central venous catheterization in patient management, whereas complications involving vertebral veins are a rare occurrence. CASE: A 73-year-old male suspected to have a urothelial carcinoma was scheduled for elective left nephroureterectomy. During central venous catheterization using the anatomic landmark technique to target the internal jugular vein, a guidewire is inadvertently inserted into the suspected vertebral vein. Following the correction of the catheterization, a radiologist reviewed the preoperative enhanced computed tomography and confirmed that the initially punctured vessel was the vertebral vein. On the third day after surgery, the central venous catheter was removed, and the patient did not exhibit any complications, such as bleeding, swelling, and neurological symptoms. CONCLUSIONS: The use of ultrasonography during central venous catheterization is recommended to evaluate the anatomy of the puncture site and prevent misinsertion of the catheter, which can lead to several complications.

Management of unanticipated difficult airway in a patient with well-visualized vocal cords using video laryngoscopy - A case report.

BACKGROUND: Difficult airway occurs due to anatomical abnormalities of the airway that can be predicted through airway assessments; however, abnormalities beyond the vocal cord can be clinically asymptomatic and undetected until intubation failure to advance the endotracheal tube. CASE: We present a case of an unanticipated difficult airway in a stuporous 80-year-old female with a recent history of intracerebral hemorrhage and prolonged intubation. She required emergency ventriculo-peritoneal shunt surgery due to the progression of her hydrocephalus. Under anesthesia, facemask ventilation was easy and video laryngoscopy provided a full view of the glottis; however, endotracheal tube (ETT) entry failed. We suspected stenosis beyond the vocal cord, and a smaller diameter ETT was inserted and maintained for airway management during emergency surgery. Postoperative neck computed tomography findings revealed laryngotracheal stenosis (LTS). CONCLUSIONS: Anesthesiologists should be aware that LTS may be asymptomatic and consider difficult airway guidelines in patients with history of prolonged endotracheal intubation.

Effect of neoadjuvant chemotherapy on effect-site concentration of propofol for sedation in patients with breast cancer.

BACKGROUND: Some studies have demonstrated that chemotherapy drugs enhance sensitivity to anesthetics owing to its systemic toxicity, while others have demonstrated that chemotherapy drugs have no effect. This study aimed to determine whether neoadjuvant chemotherapy influences the effect-site concentration (Ce) of propofol for sedation in patients withbreast cancer. METHODS: This study included patients aged 19-75 years who were scheduled to undergobreast cancer surgery under general anesthesia. Patients who received neoadjuvant chemotherapy were assigned to group C, whereas those who never received chemotherapy wereassigned to group N. Propofol was administered through an effect-site target-controlled infusion, and the Modified Observer's Assessment of Alertness/Sedation scale (MOAA/S) scoreand Bispectral Index (BIS) were recorded. When the plasma concentration and Ce wereequal to the target Ce, and if the MOAA/S score did not change, the target Ce was increasedby 0.2 µg/ml; otherwise, the Ce was maintained for 2 min and then increased. This processwas repeated until the MOAA/S score became 0. RESULTS: No significant differences were observed in Ce values at each sedation level between both groups. Ce values for loss of consciousness (LOC) of groups C and N were 2.76± 0.29 and 2.67 ± 0.27 µg/ml (P = 0.285), respectively. However, the BIS value at LOC ofgroup C (63.87 ± 7.04) was lower than that (68.44 ± 6.01) of group N (P = 0.018). CONCLUSIONS: Neoadjuvant chemotherapy for breast cancer has no effect on the Ce ofpropofol for sedation.

Verification of the performance of the Bispectral Index as a hypnotic depth indicator during dexmedetomidine sedation.

BACKGROUND: Differences in the effects of propofol and dexmedetomidine sedation on electroencephalogram patterns have been reported previously. However, the reliability of the Bispectral Index (BIS) value for assessing the sedation caused by dexmedetomidine remains debatable. The purpose of this study is to evaluate the correlation between the BIS value and the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale in patients sedated with dexmedetomidine. METHODS: Forty-two patients (age range, 20-80 years) who were scheduled for elective surgery under spinal anesthesia were enrolled in this study. Spinal anesthesia was performed using 0.5% bupivacaine, which was followed by dexmedetomidine infusion (loading dose, 0.5-1 µg/kg for 10 min; maintenance dose, 0.3-0.6 µg/kg/h). The MOAA/S score was used to evaluate the level of sedation, and the Vital Recorder program was used to collect data (vital signs and BIS values). RESULTS: A total of 215082 MOAA/S scores and BIS data pairs were analyzed. The baseline variability of the BIS value was 7.024%, and the decrease in the BIS value was associated with a decrease in the MOAA/S score. The correlation coefficient and prediction probability between the two measurements were 0.566 (P < 0.0001) and 0.636, respectively. The mean ± standard deviation values of the BIS were 87.22 ± 7.06, 75.85 ± 9.81, and 68.29 ± 12.65 when the MOAA/S scores were 5, 3, and 1, respectively. Furthermore, the cut-off BIS values in the receiver operating characteristic analysis at MOAA/S scores of 5, 3, and 1 were 82, 79, and 73, respectively. CONCLUSION: The BIS values were significantly correlated with the MOAA/S scores. Thus, the BIS along with the clinical sedation scale might prove useful in assessing the hypnotic depth of a patient during sedation with dexmedetomidine.

Effect of chemotherapy on effect-site concentration of propofol for loss of consciousness in patients with colorectal cancer.

BACKGROUND: The depth of anesthesia is an essential factor in surgical prognosis. The neurotoxic effect of chemotherapeutic drugs affects the sensitivity to anesthetics. This study was conducted to determine whether the effect-site concentration (Ce) of propofol for loss of consciousness (LOC) differs in patients undergoing preoperative chemotherapy. METHODS: A total of 60 patients scheduled for surgery for colorectal cancer under general anesthesia were included in this study. Patients who had received chemotherapy comprised the experimental (C) group, and those without a previous history of chemotherapy comprised the control (N) group. Propofol was administered as an effect-site target-controlled infusion, and the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scores were evaluated. When the plasma concentration and Ce were similar, and if the MOAA/S score did not change, the target Ce was increased by 0.2 µg/ml; otherwise, the Ce was maintained for 2 min and then increased. RESULTS: The Ce values of propofol for loss of verbal contact (LVC) in groups C and N were 2.40 ± 0.39 and 2.29 ± 0.39 µg/ml (P = 0.286), respectively, and those for LOC in groups C and N were 2.69 ± 0.43 and 2.50 ± 0.36 µg/ml (P = 0.069), respectively. No significant difference was observed in Ce values between the two groups. CONCLUSIONS: Chemotherapy had no effect on the Ce of propofol for LVC and LOC in patients with colorectal cancer. We do not recommend reducing the dose of propofol for the induction of LOC in patients with colorectal cancer undergoing chemotherapy.

Roles of NADPH oxidases in cisplatin-induced reactive oxygen species generation and ototoxicity.

In our previous study, we clearly demonstrated the roles of pro-inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-1beta (IL-1beta), and IL-6, and subsequent reactive oxygen species (ROS) generation on the pathogenesis of cisplatin ototoxicity in vitro and in vivo. ROS generation in cisplatin-treated HEI-OC1 auditory cells was also correlated with changing mitochondrial membrane potential. However, the roles of NADPH oxidase in cisplatin-induced ROS generation and ototoxicity have not been fully elucidated. Herein, immunohistochemical studies demonstrated that treatment of cisplatin induced the expression of NADPH oxidase isoforms NOX-1 and NOX-4 in HEI-OC1 auditory cells. Expression of mRNA for NOX-1, NOX-4, NOXO1, NOXA1, p47(phox), and p67(phox) was also increased. Inhibition of NADPH oxidase with diphenyleniodonium chloride or apocynin abolished ROS production and the subsequent apoptotic cell death in cisplatin-treated cells. Furthermore, suppression of NOX1 and NOX4 expression by small interfering RNA transfection markedly abolished the cytotoxicity and ROS generation by cisplatin. Together, our data suggest that ROS generated, in part, through the activation of NADPH oxidase plays an essential role in cisplatin ototoxicity.