Challenge Journal Publications (TULPAR Academic Publishing)
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Radiological evaluation of central venous catheter tip malposition
Full text linkBackground: Malposition of central venous catheters is a potentially severe but often preventable complication. This study aimed to assess the radiological distribution of central venous catheter tip positions and to discuss malposition mechanisms based on anatomical and radiographic literature.Methods: A retrospective analysis of 374 patients who underwent intraoperative central venous catheter insertion between January 2022 and December 2023 was conducted. Radiographs were evaluated using a carina-based classification system: Zones A–C (normal) and Zone D (malposition). Data were analyzed retrospectively.Results: The right internal jugular vein was the most commonly preferred access site, used in 80.0% of cases. Zone A: 52.3%, Zone B: 18.5%, Zone C: 17.8%, Zone D (malposition): 11.4%. There was no statistically significant association between catheter size and malposition (p>0.05).Conclusion: Utilizing the carina as a reference point during post-procedural imaging is essential for accurate catheter tip localization. Adjunctive modalities—including intracavitary ECG, ultrasound, and radiography—contribute to complication reduction and procedural safety
Predicting shear strength in reinforced concrete deep beams through finite element modeling of diverse concrete materials
Full text linkThis study investigates the prediction of the strength of reinforced concrete deep beams, critical components in urban infrastructure, by evaluating their load-carrying capacities through finite element modeling and nonlinear inelastic analyses using LS-DYNA software. Four widely used concrete material models were examined: Mat084/085, Mat159, Mat072R3, and Mat016. Analyses were conducted on two single-span and four double-span beams with varying reinforcement configurations and an aspect ratio of 1.0, based on well-documented experimental setups. Comparative analyses of force-displacement behavior and stress distributions revealed significant differences in shear strength predictions across the models, with Mat159 providing the most accurate results. These findings establish a reliable and cost-effective approach for predicting the capacities of deep beams, reducing reliance on extensive experimental testing. The study contributes valuable insights for improving strength predictions in critical infrastructure applications such as bridges and foundations
The mechanical properties of cement mortar reinforced with silica fume subjected to sulfate and chloride environment
Full text linkThis study investigates the effect of incorporating micro-sized silica fume on the mechanical properties and durability of cement mortar when exposed to sulfate and chloride environments. Mortar samples were prepared by replacing cement with micro-sized silica fume in varying proportions of 5%, 10%, 15%, 20%, 25%, 30%, and 35% by weight. The specimens were cured in water and chemically aggressive conditions, including 5% and 10% sodium sulfate solutions, as well as mixtures of 5% and 10% sodium chloride solutions, to simulate real-world exposure to such environments. Experimental results revealed that the addition of silica fume significantly enhanced the mortar's resistance to chemical deterioration caused by sulfates and chlorides. This improvement is attributed to the pozzolanic reaction of silica fume, which contributed to denser microstructures, reduced porosity, and a stronger bond within the matrix. Among the tested proportions, the optimal replacement ratios for achieving the best balance between mechanical strength and durability were identified up to 20%. These findings highlight the efficiency of silica fume as a supplementary cementitious material in mitigating the adverse effects of aggressive chemical agents. Such modifications can be particularly valuable in improving the service life of concrete structures exposed to harsh environmental conditions, enhancing sustainability and cost-effectiveness in construction practices
Unexpected venous anomaly around the brachial plexus during supraclavicular block: A case report
Full text linkAnatomical variations in the supraclavicular region can greatly affect the success and safety of regional anesthesia techniques, particularly supraclavicular brachial plexus blocks. Identifying these variations is essential to minimize risks. This case involves a 32-year-old male patient with a distal humeral fracture, where an ultrasound-guided supraclavicular block revealed an unusual venous structure encircling the brachial plexus. This atypical vein could pose significant risks, including vascular injury, local anesthetic toxicity, and even cardiac arrest, depending on the anesthetic uBased on its anatomical location and Doppler features, the vein was hypothesized to originate from the subclavian or external jugular vein. This finding underscores the critical importance of thorough ultrasound evaluation and real-time guidance during the procedure to avoid complications. Recognizing such anatomical anomalies is vital to ensuring patient safety, and the integration of ultrasound into routine regional anesthesia practice enhances both precision and effectiveness
Awake laparoscopic cholecystectomy under thoracal segmental spinal anesthesia and intermediate cervical plexus block: A case series
Full text linkLaparoscopic cholecystectomy (LC) is the preferred approach for treating gallstone disease because of its minimally invasive characteristics. However, factors such as increased intra-abdominal pressure, pneumoperitoneum, and positional changes present significant challenges in anesthetic management. While LC is typically performed under general anesthesia, thoracic segmental spinal anesthesia and cervical plexus block have emerged as effective alternatives in patients for whom general anesthesia poses a high risk. This study reports the use of thoracic spinal anesthesia combined with cervical plexus block in patients where general anesthesia is considered risky. After obtaining informed consent for awake laparoscopic surgery, anesthesia was managed under appropriate monitoring. The combination of spinal anesthesia and cervical plexus block allowed for the successful completion of the procedure, with minimal complications observed in the early postoperative period. In conclusion, thoracic segmental spinal anesthesia and intermediate cervical plexus block offer a safe and effective alternative for patients at high risk for general anesthesia
The effects of lycopene in lung injury associated with cecum ligation and perforation-induced sepsis in rats: An investigative animal experiment study
Full text linkBackground: The primary aim of this study is to evaluate the effect of lycopene on serum interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) levels in rats subjected to sepsis induced by the cecal ligation and perforation (CLP) method, as well as to assess the impact of lycopene on inflammation in the lungs, which is the first organ affected by sepsis.Methods: Twenty-four male rats were divided into four groups - control (healthy group), sepsis (CLP group), sepsis + lycopene 100 mg/kg (L100 group), and sepsis + lycopene 200 mg/kg (L200 group). Lycopene was administered by gastric lavage at doses of 100 mg/kg to the L100 group and 200 mg/kg to the L200 group. Intracardiac blood samples were collected 18 h after CLP for serum IL-1β and IL-6 level analysis. Lung tissue specimens were also collected for histopathological examination.Results: IL-1β levels decreased significantly in the L100 and L200 groups compared to the CLP group (p<0.001). Both doses of lycopene statistically significantly reduced serum IL-6 levels in the L100 and L200 groups compared to the CLP group. Serum IL-6 levels also decreased significantly in the L200 group compared to the L100 group (p<0.001).The degree of inflammation, vascular congestion and edema decreased significantly in the L200 group compared to the CLP group (p<0.001).Conclusion: Use of lycopene in rats with CLP-induced sepsis reduced serum IL-1β and IL-6 levels and inflammation in lung tissue at histopathological examination. Lycopene can be more effective at a dosage of 200 mg/kg
Effects on cardiopulmonary bypass duration and optic nerve sheath diameter changes
Full text linkBackground: Cardiopulmonary bypass (CPB) causes disruption of the blood-brain barrier and cerebral autoregulation for many reasons. The resulting cerebral edema causes an increase in intracranial pressure. Ultrasonographic optic nevre sheath diameter (ONSD) measurement is one of the non-invasive methods that provides information about intracranial pressure. Numerous studies have demonstrated a correlation between ONSD and intracranial pressure (ICP). We aimed to investigate ONSD changes during CPB and the relationship between these changes and CPB duration.Methods: Twenty six patients aged between 18-75 years, with an ASA score of II or III, which underwent cardiac surgery with CPB are included to the study. ONSD measurements were made throughout surgery and data were recorded.Results: ONSD values increased significantly at 45 and 90 min of CPB and end of the surgery compared to pre-CPB values for both eyes. There was no significant difference between 45 and 90 min. during CPB. A critical ONSD value was detected in 12 patients during CPB. No patient developed neurologic adverse events in the postoperative period.Conclusion: ONSD increased during CPB regardless of duration. With the data obtained from our study, we cannot say that the increase in ONSD will be a predictor of postoperative neurological complications
Retrospective comparison of anesthetic effects of bupivacaine and bupivacaine + dexmedetomidine in infraclavicular brachial plexus block in upper limb surgery
Full text linkBackground: The objective of this study was to evaluate the anesthetic efficacy of dexmedetomidine as an adjuvant to bupivacaine in infraclavicular brachial plexus blocks administered for surgical procedures involving the hand and forearm.Materials and Methods: 84 patients, aged between 18-70 years, who underwent elective hand and forearm surgery in between January 2021 and July 2021, had American Society of Anesthesiologists (ASA) classification I-II, and were anesthetized with ultrasound-guided infraclavicular brachial plexus block were included in the study. Group B (n=42): 20 ml bupivacaine 0.5%+20 ml SF, Group B+D (n=42): 20ml bupivacaine 0.5% + 1 mcg/kg dexmedetomidine diluted to a volume of 20 mL was selected from the patients who underwent block. Demographic information of the patients were taken from the preoperative anesthesia evaluation form and recorded. From the information recorded in the patient follow-up form, peak heart rate, mean arterial pressure, oxygen saturation percentage, Visual Analogue Scale (VAS) scores, pinprick test score and Bromage score were recorded as study data.Results: Compared to group B, the onset time of sensory and motor blockade was statistically significantly earlier and the duration of sensory block, motor block and analgesia was statistically significantly longer in group B+D (p<0.05). In Group B+D, VAS score was statistically significantly lower at 10th, 20th, 8th and 12th hours (p<0.05).Conclusions: The addition of 1 mcg/kg dexmedetomidine to 20 ml of 0.5% bupivacaine in infraclavicular brachial plexus block was found to significantly accelerate the onset of sensory and motor block, and to extend the duration of motor block, sensory block, and postoperative analgesia
Nonlinear in-plane response of 3D-printed concrete walls with varied infill patterns: Experimental mix design and numerical structural assessment
Full text linkThis study investigates the nonlinear in-plane structural behavior of 3D-printed concrete wall elements with two representative internal infill patterns ‒ lattice (L) and triangular (T) ‒ using finite element modeling informed by experimentally derived material properties. A printable concrete mixture was specifically developed using CEM I 42.5 R Portland cement, silica sand, and hydroxypropyl methylcellulose (HPMC) as a viscosity-modifying agent. Conventional cast specimens (40×40×160 mm³) achieved a 28-day flexural strength of 8.7 MPa and a compressive strength of approximately 63 MPa. Nonlinear behavior of wall panels with both infill types was investigated using numerical methods with advanced constitutive laws. These models account for the distinct compressive–tensile response of concrete and damage evolution under monotonic lateral loading, allowing assessment of the influence of geometry on load-bearing capacity and failure mechanisms. The results reveal that both infill patterns exhibit nonlinear load–displacement responses with an initial elastic regime, an early localized cracking peak, followed by a notable recovery in load-bearing capacity, and subsequently a global peak load prior to progressive post-peak softening. While the overall performance of both infill types was comparable, the T pattern exhibited a marginally higher peak load (1.7–2.7%) and improved ductility relative to the L form. These distinctions are attributed to the T-pattern’s more efficient diagonal force transfer and the development of a single continuous diagonal shear band, as opposed to the L-pattern’s multiple discontinuous cracks and broader damage zones