Ultrasound guided cannulation of the right subclavian vein via a supraclavicular approach for the placement of a ventriculoatrial shunt.

Central venous cannulation is usually performed via the internal jugular vein (IJV) or subclavian vein (SclV) using the Seldinger technique. The puncture of the SclV can be achieved supraclavicular which was described by Yoffa in 1965. The original approach by Yoffa is based on anatomical landmarks. Ventriculoatrial (VA) shunts in patients suffering from hydrocephalus are becoming more common. It is the procedure of choice in patients with ventriculoperitoneal (VP) shunt complications. We present a case of a female patient with a complex cervical venous anatomy and an obscure inaccessible right internal jugular vein (IJV). Subsequently, we decided to use an ultrasound guided supraclavicular approach to the right subclavian vein for implantation of a VA shunt.

Multiple Cerebral Infarctions and Rhabdomyolysis After Sildenafil Citrate (Viagra®) Intoxication: A Case Report.

BACKGROUND: Sildenafil citrate (Viagra®) is used to treat male erectile dysfunction; however, little is known about the effects of sildenafil overdose and intoxication. We report a patient who presented with cerebral infarction and rhabdomyolysis after intentional sildenafil intoxication. CASE REPORT: A 61-year-old man visited the Emergency Department complaining of dysarthria about 1 h after taking more than 30 sildenafil tablets with the intention to commit suicide. Dysarthria and dizziness were observed, but there were no other neurological symptoms. The creatine kinase level was elevated to 3118 U/L, and the patient was diagnosed with rhabdomyolysis. Brain magnetic resonance imaging revealed multiple scattered acute cerebral infarctions in both midbrain artery branches. At 4 h post-intoxication, the dysarthria had improved and we initiated dual antiplatelet therapy for cerebral infarction. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians should be able to anticipate and treat complications like cerebral infarction and rhabdomyolysis after sildenafil intoxication.

Lower Patient Height and Weight Are Predisposing Factors for Complex Radial Arterial Catheterization.

Background: Radial artery (RA) catheterization for invasive blood pressure monitoring is often performed via palpation, and an ultrasound is used secondarily only in case of multiple unsuccessful attempts. Although more elaborate, it has been shown that primary ultrasound-guided catheterization may be advantageous compared with palpation. The aim of this study was to identify factors associated with difficult RA catheterization. Methods: Left RA ultrasound assessments were performed in patients with indicated invasive blood pressure monitoring the day before surgery. RA catheterization was performed by personnel blinded to the ultrasound results. Based on the number of attempts needed for successful catheter placement, the cohort was divided into uncomplicated (group 1) and difficult (more than one attempt, group 2) catheterization cases. Cases subjected to primary ultrasound were excluded from the analysis. Results: Body weight, height and surface area (BSA) of patients in group 2 (n = 16) were significantly lower than those of patients in group 1 (n = 25), and internal RA diameters were significantly smaller in group 2 patients. In the whole cohort, BSA was significantly associated with distal and proximal internal RA diameters. In contrast, no differences were observed in the skin-to-artery distance, the longitudinal axis deviation (kinking) or blood flow velocity. Median time to successful catheterization was 77 (47-179) s. Prolonged time needed for cannulation was significantly associated with lower body weight, BMI and BSA, and with reduced distal and proximal internal RA diameter. Conclusions: RA catheterization performed through pulse palpation may be difficult, especially in adult patients with lower body weight and height, due to reduced arterial diameters. Initial use of ultrasound in these patients may reduce first-attempt failure, preventing procedural delays and patient discomfort.

Dexamethasone therapy prevents delayed neuropsychiatric sequelae after carbon monoxide poisoning: a prospective registry-based study.

BACKGROUND: Delayed neuropsychiatric sequelae are major complications of carbon monoxide poisoning; carbon monoxide triggers brain oxidation and inflammation. Corticosteroids such as dexamethasone modulate neurological damage after carbon monoxide poisoning through anti-inflammatory actions and immune response inhibition. However, it is not known whether corticosteroids prevent delayed neuropsychiatric sequelae. We thus studied whether dexamethasone reduced the incidence of delayed neuropsychiatric sequelae. METHODS: This registry-based study enrolled patients with carbon monoxide poisoning treated in a Korean tertiary care hospital from March 1st, 2020 to November 30th, 2021. Data of patients were prospectively collected during the study period, and retrospectively analyzed. One group received intravenous dexamethasone. We performed multivariable logistic regression analysis to identify factors associated with delayed neuropsychiatric sequelae. RESULTS: A total of 128 patients were enrolled, of which 99 patients received dexamethasone therapy and 29 patients did not. The incidences of delayed neuropsychiatric sequelae in the dexamethasone and non-dexamethasone groups were 16.2% and 37.9%, respectively. Multivariable logistic regression analysis revealed that dexamethasone use (odds ratio = 0.122, 95% confidence interval 0.031-0.489) and a higher Glasgow Coma Scale (odds ratio = 0.818, 95% confidence interval 0.682-0.981) was associated with a lower incidence of delayed neuropsychiatric sequelae. CONCLUSION: Early dexamethasone treatment was significantly associated with a decreased incidence of delayed neuropsychiatric sequelae. A higher Glasgow Coma Scale at presentation also was associated with a lower incidence of delayed neuropsychiatric sequelae.

A call for immediate climate action in anesthesiology: routine use of minimal or metabolic fresh gas flow reduces our ecological footprint.

PURPOSE: Climate change is a global threat, and inhalational anesthetics contribute to global warming by altering the photophysical properties of the atmosphere. On a global perspective, there is a fundamental need to reduce perioperative morbidity and mortality and to provide safe anesthesia. Thus, inhalational anesthetics will remain a significant source of emissions in the foreseeable future. It is, therefore, necessary to develop and implement strategies to minimize the consumption of inhalational anesthetics to reduce the ecological footprint of inhalational anesthesia. SOURCE: We have integrated recent findings concerning climate change, characteristics of established inhalational anesthetics, complex simulative calculations, and clinical expertise to propose a practical and safe strategy to practice ecologically responsible anesthesia using inhalational anesthetics. PRINCIPAL FINDINGS: Comparing the global warming potential of inhalational anesthetics, desflurane is about 20 times more potent than sevoflurane and five times more potent than isoflurane. Balanced anesthesia using low or minimal fresh gas flow (≤ 1 L·min-1) during the wash-in period and metabolic fresh gas flow (0.35 L·min-1) during steady-state maintenance reduces CO2 emissions and costs by approximately 50%. Total intravenous anesthesia and locoregional anesthesia represent further options for lowering greenhouse gas emissions. CONCLUSION: Responsible anesthetic management choices should prioritize patient safety and consider all available options. If inhalational anesthesia is chosen, the use of minimal or metabolic fresh gas flow reduces the consumption of inhalational anesthetics significantly. Nitrous oxide should be avoided entirely as it contributes to depletion of the ozone layer, and desflurane should only be used in justified exceptional cases.

RéSUMé: OBJECTIF: Les changements climatiques constituent une menace mondiale et les anesthésiques volatils contribuent au réchauffement climatique en modifiant les propriétés photophysiques de l'atmosphère. Dans une perspective mondiale, il est fondamentalement nécessaire de réduire la morbidité et la mortalité périopératoires et de procurer une anesthésie sécuritaire. Par conséquent, les agents volatils demeureront une source importante d'émissions dans un avenir proche. Il est donc nécessaire d'élaborer et de mettre en œuvre des stratégies pour minimiser la consommation d'anesthésiques volatils afin de réduire l'empreinte écologique de l'anesthésie par inhalation. SOURCES: Nous avons intégré les découvertes récentes concernant les changements climatiques, les caractéristiques des anesthésiques volatils connus, des calculs de simulation complexes et l'expertise clinique pour proposer une stratégie pratique et sécuritaire pour exercer une anesthésie écologiquement responsable en utilisant des anesthésiques volatils. CONSTATATIONS PRINCIPALES: En comparant le potentiel de réchauffement planétaire des anesthésiques volatils, le desflurane est environ 20 fois plus puissant que le sévoflurane et cinq fois plus puissant que l'isoflurane. Une anesthésie équilibrée avec un débit de gaz frais faible ou minimal (≤ 1 L·min-1) pendant la période de mise en route ('wash-in') et le débit métabolique de gaz frais (0,35 L·min-1) pendant le maintien à l'état d'équilibre réduit le CO2 et les coûts d'environ 50 %. L'anesthésie intraveineuse totale et l'anesthésie locorégionale représentent d'autres options pour réduire les émissions de gaz à effet de serre. CONCLUSION: Les choix responsables en matière de prise en charge anesthésique devraient accorder la priorité à la sécurité des patients et à l'évaluation de toutes les options disponibles. Si l'anesthésie par inhalation est choisie, l'utilisation d'un débit minimal ou métabolique de gaz frais réduit considérablement la consommation d'anesthésiques volatils. Le protoxyde d'azote doit être complètement évité car il contribue à l'appauvrissement de la couche d'ozone, et le desflurane ne doit être utilisé que dans les cas exceptionnels et justifiés.

Sustainable work in anaesthesiology and intensive care medicine.

The climate crisis is omnipresent and one of the most pressing challenges of the 21st century. In the position paper "Ecological sustainability in anaesthesiology and intensive care medicine", the Professional Association of German Anesthesiologists (BDA) and the German Society for Anesthesiology and Intensive Care Medicine (DGAI) made specific recommendations which contribute to a consistent and sustainable reduction in CO2 emissions. This article highlights the aspects of the position paper which the authors believe can be easily implemented in clinical practice and have a major effect on reducing CO2 emissions. The recommendations focus on the topics of medication, medical products, waste management, mobility, energy management, research and teaching with practical examples and results from the Green Team (Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn) and from the toolkit of the DGAI/BDA. Ways are shown to limit inhalation anesthetic-caused CO2-emissions, to reduce drug waste, to change single-use for reusable materials and to develop sustainable waste concepts.

The value of real-time ultrasound-guidance for definite placement of a right supraclavicular subclavian central venous catheter.

Central venous catheters (CVC) are widely used in critically ill patients and in those undergoing major surgery. Significant adverse events, such as pneumothorax and hemothorax, can be caused by needle insertion during CVC insertion. CVC misplacement is less often described, yet equally important, as it can lead to deleterious complications.Here, we describe a case in which misplacement of a guidewire following infraclavicular puncture of the right axillary vein was detected by continuous ultrasound employing the right supraclavicular fossa view. Utilizing this ultrasound view, the insertion approach to the vessel was changed and correct CVC placement could be achieved.While ultrasound guidance is widely accepted for vessel puncture, this case demonstrates the value of continuous ultrasound guidance for the entire process of CVC insertion: vessel puncture, correct guidewire advancement, catheter placement, and exclusion of complications such as pneumothorax. It also shows that there should be a high index of suspicion for guidewire misplacement, even after successful venipuncture.In conclusion, ultrasound protocols covering the complete CVC insertion process should be implemented into current clinical practice.

Point-of-Care Ultrasound-Guided Protocol to Confirm Central Venous Catheter Placement in Pediatric Patients Undergoing Cardiothoracic Surgery: A Prospective Feasibility Study.

BACKGROUND: Central venous catheters (CVC) are commonly required for pediatric congenital cardiac surgeries. The current standard for verification of CVC positioning following perioperative insertion is postsurgical radiography. However, incorrect positioning may induce serious complications, including pleural and pericardial effusion, arrhythmias, valvular damage, or incorrect drug release, and point of care diagnostic may prevent these serious consequences. Furthermore, pediatric patients with congenital heart disease receive various radiological procedures. Although relatively low, radiation exposure accumulates over the lifetime, potentially reaching high carcinogenic values in pediatric patients with chronic disease, and therefore needs to be limited. We hypothesized that correct CVC positioning in pediatric patients can be performed quickly and safely by point-of-care ultrasound diagnostic. METHODS: We evaluated a point-of-care ultrasound protocol, consistent with the combination of parasternal craniocaudal, parasternal transversal, suprasternal notch, and subcostal probe positions, to verify tip positioning in any of the evaluated views at initial CVC placement in pediatric patients undergoing cardiothoracic surgery for congenital heart disease. RESULTS: Using the combination of the four views, the CVC tip could be identified and positioned in 25 of 27 examinations (92.6%). Correct positioning was confirmed via chest X-ray after the surgery in all cases. CONCLUSIONS: In pediatric cardiac patients, point-of-care ultrasound diagnostic may be effective to confirm CVC positioning following initial placement and to reduce radiation exposure.

Predictors of renal infarction in patients presenting to the emergency department with flank pain: A retrospective observational study.

OBJECTIVES: Flank pain is a common symptom in the emergency department and can be caused by a variety of diseases. Renal infarction (RI) is a very rare disease, and many RI patients complain of flank pain. However, there is no definitive predictor of RI when patients complain of flank pain. This study aimed to identify the clinical factors for predicting RI in patients with flank pain. METHODS: This retrospective single-center study was conducted on patients complaining of flank pain from January 2016 to March 2020 at a South Korean tertiary care hospital. Exclusion criteria included patients who did not undergo contrast-enhanced computed tomography, age < 18 years, and trauma. Demographic and laboratory data were obtained from medical records. Logistic regression analysis was conducted to identify predictors of RI occurrence. RESULTS: In all, 2,131 patients were enrolled, and 39 (1.8%) had RI. From a multivariable logistic regression analysis, an age ≥ 65 years (odds ratio [OR], 3.249; 95% confidence interval [CI], 1.366-7.725; p = 0.008), male sex (OR, 2.846; 95% CI, 1.190-6.808; p = 0.019), atrial fibrillation (OR, 10.386; 95% CI, 3.724-28.961; p < 0.001), current smoker (OR, 10.022; 95% CI, 4.565-22.001; p < 0.001), and no hematuria (OR, 0.267; 95% CI, 0.114-0.628; p = 0.002) were significantly associated with the occurrence of RI. CONCLUSIONS: Five clinical factors, i.e., age ≥ 65 years, male sex, atrial fibrillation, current smoker, and no hematuria, were significantly associated with the occurrence of RI in patients with flank pain.

Anti-Obesity and Anti-Adipogenic Effects of Chitosan Oligosaccharide (GO2KA1) in SD Rats and in 3T3-L1 Preadipocytes Models.

Excess body weight is a major risk factor for type 2 diabetes (T2D) and associated metabolic complications, and weight loss has been shown to improve glycemic control and decrease morbidity and mortality in T2D patients. Weight-loss strategies using dietary interventions produce a significant decrease in diabetes-related metabolic disturbance. We have previously reported that the supplementation of low molecular chitosan oligosaccharide (GO2KA1) significantly inhibited blood glucose levels in both animals and humans. However, the effect of GO2KA1 on obesity still remains unclear. The aim of the study was to evaluate the anti-obesity effect of GO2KA1 on lipid accumulation and adipogenic gene expression using 3T3-L1 adipocytes in vitro and plasma lipid profiles using a Sprague-Dawley (SD) rat model. Murine 3T3-L1 preadipocytes were stimulated to differentiate under the adipogenic stimulation in the presence and absence of varying concentrations of GO2KA1. Adipocyte differentiation was confirmed by Oil Red O staining of lipids and the expression of adipogenic gene expression. Compared to control group, the cells treated with GO2KA1 significantly decreased in intracellular lipid accumulation with concomitant decreases in the expression of key transcription factors, peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (CEBP/α). Consistently, the mRNA expression of downstream adipogenic target genes such as fatty acid binding protein 4 (FABP4), fatty acid synthase (FAS), were significantly lower in the GO2KA1-treated group than in the control group. In vivo, male SD rats were fed a high fat diet (HFD) for 6 weeks to induced obesity, followed by oral administration of GO2KA1 at 0.1 g/kg/body weight or vehicle control in HFD. We assessed body weight, food intake, plasma lipids, levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) for liver function, and serum level of adiponectin, a marker for obesity-mediated metabolic syndrome. Compared to control group GO2KA1 significantly suppressed body weight gain (185.8 ± 8.8 g vs. 211.6 ± 20.1 g, p < 0.05) with no significant difference in food intake. The serum total cholesterol, triglyceride, and low-density lipoprotein (LDL) levels were significantly lower in the GO2KA1-treated group than in the control group, whereas the high-density lipoprotein (HDL) level was higher in the GO2KA1 group. The GO2KA1-treated group also showed a significant reduction in ALT and AST levels compared to the control. Moreover, serum adiponectin levels were significantly 1.5-folder higher than the control group. These in vivo and in vitro findings suggest that dietary supplementation of GO2KA1 may prevent diet-induced weight gain and the anti-obesity effect is mediated in part by inhibiting adipogenesis and increasing adiponectin level.

CpG postconditioning after reperfused myocardial infarction is associated with modulated inflammation, less apoptosis, and better left ventricular function.

Postconditioning attenuates inflammation and fibrosis in myocardial infarction (MI). The aim of this study was to investigate whether postconditioning with the cytosine-phosphate-guanine (CpG)-containing Toll-like receptor-9 (TLR9) ligand 1668-thioate (CpG) can modulate inflammation and remodeling in reperfused murine MI. Thirty minutes of left descending coronary artery (LAD) occlusion was conducted in 12-wk-old C57BL/6 mice. Mice were treated with CpG intraperitoneally 5 min before reperfusion. The control group received PBS; the sham group did not undergo ischemia. M-mode echocardiography (3, 7, and 28 days) and Millar left ventricular (LV) catheterization were performed (7 and 28 days) before the hearts were excised and harvested for immunohistochemical (6 h, 24 h, 3 days, 7 days, and 28 days), gene expression (6 h, 24 h, and 3 days; Taqman RT-qPCR), protein, and FACS analysis (24 h and 3 days). Mice treated with CpG showed significantly better LV function after 7 and 28 days of reperfusion. Protein and mRNA expressions of proinflammatory and anti-inflammatory cytokines were significantly induced after CpG treatment. Histology revealed fewer macrophages in CpG mice after 24 h, confirmed by FACS analysis with a decrease in both classically M1- and alternative M2a-monocytes. CpG treatment reduced apoptosis and cardiomyocyte loss and was associated with induction of adaptive mechanisms, e.g., of heme-oxigenase-1 and ß-/α-myosin heavy chain (MHC) ratio. Profibrotic markers collagen type Iα (Col-Ια) and Col-III induction was abrogated in CpG mice, accompanied by fewer myofibroblasts. This led to the formation of a smaller scar. Differential matrix metalloproteinase (MMP)/tissue inhibitor of metalloproteinase (TIMP) expression contributed to attenuated remodeling in CpG, resulting in preserved cardiac function in a Toll-like receptor 1- and TLR9-dependent manner. Our study suggests a cardioprotective mechanism of CpG postconditioning, involving Toll-like receptor-driven modulation of inflammation. This is followed by attenuated remodeling and preserved LV function.NEW & NOTEWORTHY Cytosine-phosphate-guanine (CpG) postconditioning seems to mediate inflammation via Toll-like receptor-1 and Toll-like receptor-9 signaling. Enhanced cytokine and chemokine expressions are partly attenuated by IL-10 and matrix metalloproteinase-8 (MMP8) induction, being associated with lower macrophage infiltration and M1-monocyte differentiation. Furthermore, switch from α- to ß-MHC and balanced MMP/TIMP expression led to lesser cardiomyocyte apoptosis, smaller scar size, and preserved cardiac function. Data of pharmacological postconditioning have been widely disappointing to date. Our study suggests a new pathway promoting myocardial postconditioning via Toll-like receptor activation.

Inhibitory Effects of Roseoside and Icariside E4 Isolated from a Natural Product Mixture (No-ap) on the Expression of Angiotensin II Receptor 1 and Oxidative Stress in Angiotensin II-Stimulated H9C2 Cells.

Hypertension is a major risk factor for the development of cardiovascular diseases. This study aimed to elucidate whether the natural product mixture No-ap (NA) containing Pine densiflora, Annona muricate, and Monordica charantia, or its single components have inhibitory effects on hypertension-related molecules in Angiotensin II (Ang II)-stimulated H9C2 cells. Individual functional components were isolated and purified from NA using various columns and solvents, and then their structures were analyzed using ESI⁻MS, ¹H-NMR, and 13H-NMR spectra. H9C2 cells were stimulated with 300 nM Ang II for 7 h. NA, telmisartan, ginsenoside, roseoside (Roseo), icariside E4 (IE4), or a combination of two components (Roseo and IE4) were administered to the cells 1 h before Ang II stimulation. The expression and activity of hypertension-related molecules or oxidative molecules were determined using RT-PCR, western blot, and ELISA. Ang II stimulation increased the expression of Ang II receptor 1 (AT1), tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), tumor growth factor-ß (TGF-ß) mRNA, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and the levels of hydrogen peroxide (H2O2) and superoxide anion (•O2-) and reduced anti-oxidant enzyme activity. NA significantly improved the expression or activities of all hypertension-related molecules altered in Ang II-stimulated cells. Roseo or IE4 pretreatment either decreased or increased the expression or activities of all hypertension-related molecules similar to NA, but to a lesser extent. The pretreatment with a combination of Roseo and IE4 (1:1) either decreased or increased the expression of all hypertension-related molecules, compared to each single component, revealing a synergistic action of the two compounds. Thus, the combination of single components could exert promising anti-hypertensive effects similar to NA, which should be examined in future animal and clinical studies.

Electrocardiography-controlled central venous catheter tip positioning in patients with atrial fibrillation.

INTRODUCTION:: A significant increase of the p-wave of a real-time intracavitary electrocardiography is a reliable and safe method to confirm the central venous catheter tip position close to the atrium. However, conflicting data about the feasibility of electrocardiography exist in patients with atrial fibrillation. METHODS:: An observational prospective case-control cohort study was set up to study the feasibility and accuracy of the electrocardiography-controlled central venous catheter tip placement in 13 patients with atrial fibrillation versus 10 patients with sinus rhythm scheduled for elective surgery. Each intervention was crosschecked with ultrasound-guided positioning via right supraclavicular fossa view and chest radiography. Ultrasound-guided supraclavicular venipuncture of the right subclavian vein and guidewire advancement were performed. A B-mode view of the superior vena cava and the right pulmonary artery was obtained to visualize the J-tip of the guidewire. The central venous catheter was advanced over the guidewire and the electrocardiography was derived from the J-tip of the guidewire protruding from the central venous catheter tip. Electrocardiography was read for increased p- and atrial fibrillation waves, respectively, and insertion depth was compared with the ultrasound method. RESULTS:: Electrocardiography indicated significantly increasing fibrillation and p-waves, respectively, in all patients and ultrasound-guided central venous catheter positioning confirmed a tip position within the lower third of the superior vena cava. CONCLUSION:: Electrocardiography-guided central venous catheter tip positioning is a feasible real-time method for patients with atrial fibrillation. Combined with ultrasound, the electrocardiography-controlled central venous catheter placement may eliminate the need for postinterventional radiation exposure.

Improvement of polytrauma management-quality inspection of a newly introduced course concept.

RATIONALE, AIMS, AND OBJECTIVES: A systematic literature search for training course concepts for care of severely injured and severely ill patients respecting improvement of process and outcome yielded little data. For several years, the University Hospital of Bonn has hosted a shock-room management course which, on the one hand, communicates human factor aspects and, on the other hand, pursues interdisciplinary and interprofessional team training. The Bonn shock-room management course (BSM-course®) differs from other courses in both format and principles. The aim of this study was to evaluate the quality of the structure of the course based on course evaluations of participants and its impact on the quality of the process and results for polytrauma care. METHODS: Single-center retrospective evaluation study (2011 to 2014). It was based on data from simulator training and records from the German Trauma Registry (DGU)®. RESULTS: Subjective evaluation of participants (n = 188) of the structure quality of Bonn's shock-room management course was overall positive. Objective measures of course participant performance also improved during simulation training (P = 0.012). An increasing number of trained employees also had a positive influence in reducing process time for shock-room care. Further, the course likewise had a positive impact on documentation quality (degree of completion), with regard to 4 relevant predictive parameters. Early mortality during the first 24 hours remained constant at 6.0-6.5% between 2011 and 2013, yet it decreased to 3.1% in 2014. CONCLUSION: The BSM-course® represents a symbiosis of horizontal team approach of trauma care and human factor training. The course format is able to ensure interdisciplinary and interprofessional team training with a high degree of efficiency. Furthermore, the presented work shows that a modern course concept can improve the quality of trauma care.

Effects of Bias Pulsing on Etching of SiO2 Pattern in Capacitively-Coupled Plasmas for Nano-Scale Patterning of Multi-Level Hard Masks.

In order to study the effects of bias pulsing on the etching characteristics of a silicon dioxide (SiO2) layer using multi-level hard mask (MLHM) structures of ArF photoresist/bottom anti-reflected coating/SiO2/amorphous carbon layer (ACL)/SiO2, the effects of bias pulsing conditions on the etch characteristics of a SiO2 layer with an ACL mask pattern in C4F8/CH2F2/O2/Ar etch chemistries were investigated in a dual-frequency capacitively-coupled plasma (CCP) etcher. The effects of the pulse frequency, duty ratio, and pulse-bias power in the 2 MHz low-frequency (LF) power source were investigated in plasmas generated by a 27.12 MHz high-frequency (HF) power source. The etch rates of ACL and SiO2 decreased, but the etch selectivity of SiO2/ACL increased with decreasing duty ratio. When the ACL and SiO2 layers were etched with increasing pulse frequency, no significant change was observed in the etch rates and etch selectivity. With increasing LF pulse-bias power, the etch rate of ACL and SiO2 slightly increased, but the etch selectivity of SiO2/ACL decreased. Also, the precise control of the critical dimension (CD) values with decreasing duty ratio can be explained by the protection of sidewall etching of SiO2 by increased passivation. Pulse-biased etching was successfully applied to the patterning of the nano-scale line and space of SiO2 using an ACL pattern.

Ultrasound-guided supraclavicular central venous catheter tip positioning via the right subclavian vein using a microconvex probe.

PURPOSE: The ultrasound-guided central venous catheter (CVC) guidewire tip positioning has been demonstrated for catheterization of the right internal jugular vein. We explored the feasibility of an ultrasound-guided right subclavian vein (RScV) CVC tip positioning via a right supraclavicular approach using a microconvex probe. METHODS: Twenty patients scheduled for elective surgery were consecutively included in this observational feasibility study following written informed consent. Exclusion criteria were emergency procedure, thrombosis and obstacle to guidewire advancement. Following an ultrasound pre-scan of the superior vena cava (SVC), the RScV and the right pulmonary artery (RPA) via the right supraclavicular fossa view, a sterile ultrasound-guided venipuncture was performed. The guidewire J-tip was advanced to the distal SVC with subsequent introduction of the CVC. The final CVC tip position was confirmed with ultrasound and postoperative chest radiograph. RESULTS: In all patients, SVC, RScV and RPA were visualized in the pre-scan. Guidewire positioning and final ultrasound CVC tip confirmation in the distal SVC was successful in all patients. In two patients, needle insertion of the RScV failed and insertion site was converted to a right internal jugular vein insertion. No misplacement, arterial puncture, pneumo- or hematothorax occurred. Time for pre-scan to venipuncture was 9 min 25 sec ± 5 min 24 sec and 1 min 05 sec ± 59 sec from venipuncture until guidewire positioning (mean ± SD, n = 18). CONCLUSIONS: Ultrasound-guided CVC tip confirmation following catheterization of the right subclavian vein via a right supraclavicular approach with a microconvex probe is feasible.