Nurses' Perception of Tension, Stress, and Pressure before and during the COVID-19 Pandemic: A Multicenter Serbian Study.

The mental health of healthcare workers, especially the nursing staff in intensive care units, is crucial for the optimal functioning of healthcare systems during medical emergencies. This study implements a cross-sectional design to investigate the associations between nurses' personal characteristics, workplace challenges, and job satisfaction with the increased perception of tension, stress, and pressure at the workplace (TSPW) before and during the COVID-19 pandemic. In 2021, we surveyed 4210 nurses from 19 intensive healthcare facilities in the capital of Serbia, Belgrade, and, at that time, collected data about their perceived TSPW before and during the COVID-19 pandemic. Our study identified six predictors of the increase in TSPW, as perceived by nurses: their work in COVID-19 infectious zones (OR = 1.446), exhaustion due to work under protective equipment (OR = 1.413), uncertainty and fear of infection (OR = 1.481), a high degree of superiors' appreciation and respect (OR = 1.147), a high degree of patients' attitudes (OR = 1.111), and a low degree of work autonomy (OR = 0.889). The study's findings suggest that a solution to this issue is necessary to ensure that nurses are safe and able to alleviate the physical and mental strain that comes with prolonged use of protective equipment. Nurses on the frontline of the pandemic require better health protection, better conditions, and respect for their role. Strategies to promote mental health would help reduce nurses' stress and increase job satisfaction.

Immediate results of primary balloon dilation for congenital aortic valve stenosis predict the mid-term outcome.

BACKGROUND: Balloon valvuloplasty is the primary treatment for congenital aortic valve stenosis in our centre. We sought to determine independent predictors of reintervention (surgical repair or repeated balloon dilation) after primary valvuloplasty. METHODS: We retrospectively studied patients with congenital aortic valve stenosis who underwent balloon valvuloplasty during 2004-2018. The following risk factors were analysed: aortic valve insufficiency after balloon valvuloplasty >+1/4, post-procedural gradient across the aortic valve ≥35 mmHg, pre-interventional gradient across the valve, annulus size, use of rapid pacing, and balloon/annulus ratio. Primary outcome was aortic valve reintervention. RESULTS: In total, 99 patients (median age 4 years, range 1 day to 26 years) underwent balloon valvuloplasty for congenital aortic valve stenosis. After a mean follow-up of 4.0 years, 30% had reintervention. Adjusted risks for reintervention were significantly increased in patients with post-procedural aortic insufficiency grade >+1/4 and/or residual gradient ≥35 mmHg (HR 2.55, 95% CI 1.13-5.75, p = 0.024). Pre-interventional gradient, annulus size, rapid pacing, and balloon/annulus ratio were not associated with outcome. CONCLUSION: Post-procedural aortic valve insufficiency grade >+1/4 and/or residual gradient ≥35 mmHg in patients undergoing balloon valvuloplasty for congenital aortic valve stenosis confers an increased risk for reintervention in mid-term follow-up.

A Deep Learning Model for Automatic Detection and Classification of Disc Herniation in Magnetic Resonance Images.

Localization of lumbar discs in magnetic resonance imaging (MRI) is a challenging task, due to a vast range of shape, size, number, and appearance of discs and vertebrae. Based on a review of the cutting-edge methods, the majority of applied techniques are either semi-automatic, extremely sensitive to change in parameters, or involve further modification of the results. All of the above represents a motivation for implementing deep learning-based approaches for automatic segmentation and classification of disc herniation in MR images. This paper proposes a complete automated process based on deep learning to diagnose disc herniation. The methodology includes several steps starting from segmentation of region of interest (ROI), in this case disc area, bounding box cropping and enhancement of ROI, after which the image is classified based on convolutional neural network (CNN) into adequate classes (healthy, bulge, central, right or left herniation for axial view and healthy, L4/L5, L5/S1 level of herniation in sagittal view). The results show high accuracy of segmentation for both axial view (dice = 0.961, IOU = 0.925) and sagittal view (dice = 0.897, IOU = 0.813) images. After cropping and enhancing the region of interest, accuracy of classification was 0.87 for axial view images and 0.91 for sagittal view images. Comparison with the literature shows that proposed methodology outperforms state-of-the-art results when it comes to multiclassification problems. A fully automated decision support system for disc hernia diagnosis can assist in generating diagnostic findings in a timely manner, while human mistakes caused by cognitive overload and procedure-related errors can be reduced.

Participation in Bullying and Associated Health Characteristics, Risk Factors and Leisure Activities: A Profile of School-Age Children in Serbia.

The aim of this study was to examine the prevalence and association of school-age children's participation in bullying, focusing on their health characteristics, risk factors, and leisure activities. We performed a secondary analysis of the original data of the 2017 HBSC study to examine participation in bullying once and multiple times among school-age children in Serbia. For this purpose, a nationally representative sample of 3267 children from 64 primary and high schools in the Republic of Serbia was evaluated. The outcome variable of interest in our study was participation in bullying. Further groups of individual variables such as health characteristics, risk factors, and leisure activities were assessed. Multivariate regression analysis indicated that children who felt everyday stomach pain, irritability or bad mood, and nervousness were more likely to participate in bullying at least once compared with those who rarely or never had such symptoms by 1.46, 1.58, and 1.58 times, respectively. School-age children who reported being drunk two to three times, and four or more times in life were more likely to participate in bullying than those who reported never being drunk by 1.53 and 1.74 times, respectively. Children who reported to watch TV or other media for five or more hours per day were 2.34 times more likely to be involved in bullying at least once. Multiple regression analysis showed that students with daily stomach pain, back pain, nervousness, and dizziness were more likely to be involved in multiple bullying by 1.16, 1.62, 1.82, and 1.70 times, respectively. Students who had nightly meetings or reported being drunk four or more times in the last 30 days were more likely to be involved in multiple bullying by 2.54 and 3.47, respectively. Students who reported playing games five or more times per day were 2.70 times more likely to be involved in this multiple bullying. This study highlights the importance of professional and family education programmes for early identification of specific health symptoms in the pediatric population, as well as integration with interventions aimed at reducing alcohol abuse among school-age children.

Exploitation Characteristics of Teeth Flanks of Gears Regenerated by Three Hard-Facing Procedures.

Numerous phenomena that occur during the process of machine parts' regeneration have a significant impact on the loss of their working ability. Therefore, the properties of the working surfaces of the teeth flanks of repaired gears were analyzed in this research. The hereditary properties of the gear teeth are expressed by the interdependence of their geometric and physical-mechanical-metallurgical parameters created during the technological operations of regeneration of worn teeth by welding/hard-facing. The hard-facing was executed with three filler metal types, namely: combination Inox 18/8/6 + EDur 600, Castolin 2 and UTP 670. The tested properties included geometrical accuracy, microstructure and microhardness. Evaluation of the executed regeneration procedures was done by comparing the mentioned parameters of the regenerated gears and the new ones. The tested gears were not withdrawn from production due to damage, but they were newly manufactured and intentionally damaged gears, made of the same materials, subjected to the same manufacturing process. In this way, all influences except for the considered filler metal type were eliminated. Based on results of the conducted experiments, it was possible to establish the influence of the filler metal type on the surface characteristics of the regenerated gears' teeth flanks.

MTT based L-aminoacid oxidase activity test for determination of antivenom potency against Vipera ammodytes envenomation.

The MTT assay is routinely used to detect the activity of living cells. While working with Vipera ammodytes venom we detected the reduction of MTT without the presence of cells, in a concentration-dependent manner. By combining non-reducing PAGE, L-amino acid oxidase (LAAO) assays, and standard MTT assays, we established and confirmed that venom MTT reduction is catalyzed by only one enzyme, the LAAO. Even though it was previously known that the dimeric and tetrameric forms of LAAO are active, we conclude that the enzyme is also active in the monomeric form. Our results have led to the definition of a new MTT assay in a microtiter plate for in vitro testing of svLAAO activity i.e. from the venom of the V. ammodytes snake. Potentially, this method can be used for testing hemorrhagic venoms of other snakes as well as the LAAO neutralization capability of appropriate antivenoms.

Semiconductor Gas Sensors: Materials, Technology, Design, and Application.

This paper presents an overview of semiconductor materials used in gas sensors, their technology, design, and application. Semiconductor materials include metal oxides, conducting polymers, carbon nanotubes, and 2D materials. Metal oxides are most often the first choice due to their ease of fabrication, low cost, high sensitivity, and stability. Some of their disadvantages are low selectivity and high operating temperature. Conducting polymers have the advantage of a low operating temperature and can detect many organic vapors. They are flexible but affected by humidity. Carbon nanotubes are chemically and mechanically stable and are sensitive towards NO and NH3, but need dopants or modifications to sense other gases. Graphene, transition metal chalcogenides, boron nitride, transition metal carbides/nitrides, metal organic frameworks, and metal oxide nanosheets as 2D materials represent gas-sensing materials of the future, especially in medical devices, such as breath sensing. This overview covers the most used semiconducting materials in gas sensing, their synthesis methods and morphology, especially oxide nanostructures, heterostructures, and 2D materials, as well as sensor technology and design, application in advance electronic circuits and systems, and research challenges from the perspective of emerging technologies.

A comparison of classifiers in biomedical signal processing as a decision support system in disc hernia diagnosis.

The aim of this research was to investigate the best methodology for disc hernia diagnosis using foot force measurements from the designed platform. Based on the subjective neurological examination that examines muscle weakness on the nerve endings of the skin area on feet and concludes about origins of nerve roots between spine discs, a platform for objective recordings of the aforementioned muscle weakness has been designed. The dataset included 33 patients with pre-diagnosed L4/L5 and L5/S1 disc hernia on the left or the right side, confirmed with the MRI scanning and neurological exam. We have implemented 5 different classifiers that were found to be the most suitable for smaller dataset and investigated the accuracy of classification depending on the normalization method, linearity/non-linearity of the algorithm, and dataset splitting variation (32-1, 31-2, 30-3, 29-4 patients for training and testing, respectively). The classifier is able to distinguish between four different diagnoses L4/L5 on the left side, L4/L5 on the right side, L5/S1 on the left side and L5/S1 on the right side, as well as to recognize healthy subjects (without disc herniation). The results show that non-linear algorithms achieved better accuracy in comparison to tested linear classifiers, suggesting the expected non-linear connection between the foot force values and the level of disc herniation. Two algorithms with highest accuracy turned out to be Decision Tree and Naïve Bayes, depending on the normalization method. The system is also able to record and recognize improvements in muscle weakness after surgical operation and physical therapy.

Reevaluating the Importance of Modified Ultrafiltration in Contemporary Pediatric Cardiac Surgery.

OBJECTIVE(S): Modified ultrafiltration has gained wide acceptance as a powerful tool against cardiopulmonary bypass morbidity in pediatric cardiac surgery. The aim of our study was to assess the importance of modified ultrafiltration within conditions of contemporary cardiopulmonary bypass characteristics. METHODS: Ninety⁻eight patients (overall cohort) weighing less than 12 kg undergoing surgical repair with cardiopulmonary bypass were prospectively enrolled in a randomized protocol to receive modified and conventional ultrafiltration (MUF group) or just conventional ultrafiltration (non-MUF group). A special attention was paid to forty-nine neonates and infants weighing less than 5 kg (lower weight (LW) cohort). RESULTS: Post-filtration hematocrit was significantly higher in the MUF group for both cohorts (overall cohort p = 0.001; LW cohort p = 0.04), but not at other time points. During the postoperative course, patients in the MUF group received fewer packed red blood cells, (overall cohort p = 0.01; LW cohort p = 0.07), but required more fresh frozen plasma (overall cohort p = 0.04; LW cohort p = 0.05). There was no difference between groups in hemodynamic state, chest tube output, duration of mechanical ventilation, respiratory parameters, duration of intensive care unit, and hospitalization stay. CONCLUSIONS: If conventional ultrafiltration provides adequate hemoconcentration modified ultrafiltration does not provide additional positive benefits except for reduction in blood cell transfusion, This, however, comes at the cost of needing more fresh frozen plasma. Of particular importance is that this also applies to infants with weight bellow 5 kg where modified ultrafiltration was supposed to have the greatest positive impact.

Tricuspid atresia associated with aortopulmonary window: diagnostic and therapeutic dilemmas.

The association of tricuspid atresia with aortopulmonary window is exceptionally rare. We report a patient with tricuspid atresia, normally related great arteries, non-restrictive ventricular septal defect, and no pulmonary stenosis (type IC) with an aortopulmonary window who underwent successful initial surgical palliation. The unique anatomical feature of this case, other than the presence of the aortopulmonary window, was the absence of pulmonary stenosis at the level of either the ventricular septal defect or the pulmonary valve. All other reported cases have described some degree of restriction of anterograde pulmonary flow due to pulmonary stenosis or atresia.

Comparison of high glucose concentration blood and crystalloid cardioplegia in paediatric cardiac surgery: a randomized clinical trial.

OBJECTIVES: This study investigates the effects of high glucose content on patients undergoing cold crystalloid versus cold blood cardioplegia in terms of early clinical results, functional myocardial recovery and ischaemia-reperfusion injury in patients undergoing repair of acyanotic cardiac lesions. METHODS: Patients were randomly assigned to receive either crystalloid (n = 31) or blood cardioplegia (n = 31). Early clinical results were assessed. Changes in left ventricular fractional shortening, arterial blood lactate levels, central venous saturation, cardiac Troponin I release and blood glucose concentration were measured during the first 24 h after ischaemia. RESULTS: There was no significant difference in clinical outcomes and postoperative complication rates between groups. The postoperative changes in left ventricular function, lactate levels, central venous saturation and Troponin I were not significantly different between groups. The use of crystalloid cardioplegia was associated with significant increases in serum glucose compared with blood cardioplegia. CONCLUSIONS: A high glucose content blood cardioplegia does not show any advantage compared with crystalloid cardioplegia in terms of clinical outcomes, functional recovery and the degree of ischaemic injury in infants and children undergoing repair of acyanotic heart lesions. High glucose concentration of the cardioplegic solution might potentiate ischaemia-reperfusion injury and diminish the beneficial effects of blood cardioplegia.

[The Role of Two-Dimensional Echocardiography in Diagnostics of Coarctation of the Aorta in Newborns].

INTRODUCTION: Diagnosis of neonatal coarctation of the aorta (CoA) still presents a challenge in routine practice because of absence of reliable morphologic and functional parameters for early detection of this congenital heart defect in newborns. OBJECTIVE: The aim of this study is to identify easy obtainable two-dimensional echocardiographic parameters for detection of the CoA in newborns. METHODS: Echocardiographic evaluation was performed in 30 newborns with CoA and 20 healthy neonates (control group). Measurements of the proximal transverse arch (PTA), distal transverse arch (DTA), isthmus, distance between the left common carotid artery (LCCA) at the origin of the left subclavian artery (LSA), were obtained by two-dimensional echocardiography. Aortic arch hypoplasia was defined using Mouleart, Karl and Mee criteria, and Z-value. Index 1 was calculated as a ratio of DTA and distance between origins LCCA-LSA, Index 2 was calculated as a ratio of the ascending aorta and the distance between LCCA-LSA origins, and Index 3 was calculated as a ratio of PTA and distance between LCCA-LSA origins. RESULTS: Index 1 was significantly lower in patients with CoA in comparison with control group (0.50 vs. 1.39; p≤0.01). A cut-off point at 0.39, for Index 1, showed a sensitivity of 92% and specificity of 99% for the diagnosis of neonatal CoA, while cut off points at 0.69 and 0.44, for Index 2 and Index 3, showed the highest sensitivity and specificity for the diagnosis of CoA in newborns. CONCLUSION: By using these echo indexes, two-dimensional echocardiographic aortic arch measurement becomes a simple, reliable noninvasive method for the evaluation of aortic coarctation in newborns and may lead to earlier diagnosis and subsequent surgical correction.

[Mid-term results after complete surgical correction of transposition of the great arteries].

INTRODUCTION: Arterial switch operation (ASO) is a cardiosurgical method of choice for complete anatomical correction of transposition of great arteries. Improvement of this procedure has made considerably improved the outcome and long-term prognosis of children born with this complex congenital heart disease. OBJECTIVE: The aim of this study was to estimate the success rate of ASO through retrospective analysis of mortality and late complications. METHODS: This study included 57 children operated from 1st January 2005 until 31st December 2009. Parameters that could influence the outcome of surgery were investigated. The following late complications were investigated: neopulmonary artery stenosis, neoaortic stenosis and regurgitation, as well as clinical signs of heart failure. RESULTS: Early postoperative mortality was 15.8% (9/57 patients). During follow-up (8 to 72 months, average 36.5 months) there were no lethal outcomes. On the last echocardiography examination, 73.2% patients had neoaortic regurgitation and 67.4% patients had neopulmonary regurgitation, but all of them were mild in intensity. Neopulmonary stenosis had 32.6% of patients, but only two had moderate or severe stenosis. No one had ischemic ECG changes. Three reinterventions were performed due to serious residual problems: surgical correction of neoaortic stenosis, surgical correction of neopulmonary stenosis and transcatether balloon dilatation for aortic recoarctation. At the end of the follow-up period, only one of 46 consistently followed patients had signs of heart failure which required therapy (2.2%), while the majority of patients were without any symptoms and with good effort tolerance. CONCLUSION: Arterial switch operation has been successfully performed at our institution, with acceptable perioperative mortality and excellent late outcome.

[Outcomes of surgery for total anomalous pulmonary venous drainage].

INTRODUCTION: Total anomalous pulmonary venous connection (TAPVC) is a rare congenital heart disease and in some variants represents the only true surgical emergency in congenital heart surgery. Basic anatomical characteristic of this anomaly is an abnormal connection of pulmonary veins with systemic venous circulation. Although the results of TAPVC repair in infancy have been markedly improved in recent years, the recurrent pulmonary venous obstruction (RPVO) remains relatively frequent complication of surgical treatment. OBJECTIVE: The aim of this study was a retrospective evaluation of TAPVC repair at a single institution, identifying the risk factors associated with the increased mortality and morbidity. METHODS: Between January 2001 and January 2010, 43 consecutive patients underwent repair of TAPVC at the University Children's Hospital, with median weight of 3.8 kg (1.8-13 kg). Median age at surgery varied from 5 days to 5 years. Distribution of TAPVC types was as follows: supracardiac 19 (44%), cardiac 12(28%), infracardiac 9 (21%), and mixed 3 (7%). Eleven patients (26%) were emergencies due to obstructed drainage. RESULTS: Early mortality was 9.30% (4/43). An average time of followup/survival for 95% interval of confidence was 101.6 +/- 6.7 months. Kaplan-Meier cumulative survival was 83.7 +/- 5.7%. Freedom from reintervention after 10 years was 87.2 +/- 0.5%. The principal reason for reintervention was RPVO. CONCLUSION: Preoperative obstruction is not a risk factor of early mortality and RPVO. Low body mass (below 2.5 kg) is the only identified risk factor of early mortality. Complex morphology of the confluens, particularly in a mixed type of TAPVR, is the main risk factor of RPVO development.

Intrapericardial immature teratoma in a newborn: a case report.

Intrapericardial teratomas are extremely rare and most often benign tumours. In this paper, we have described a case of intrapericardial teratoma diagnosed prenatally and successfully operated. The presented case is noteworthy as an example of potentially catastrophic cardiorespiratory distress caused by the space-occupying nature of the tumour. A multi-disciplinary approach is mandatory because the tumour most often arises from the ascending aorta and in some cases may require the use of cardiopulmonary bypass.

L-FABP can be an early marker of acute kidney injury in children.

BACKGROUND: Acute kidney injury (AKI) is a common postoperative complication following cardiopulmonary bypass (CPB) surgery. New biomarkers to identify patients with early AKI (before increases in serum creatinine) are needed to facilitate appropriate treatment. This study aimed to test the role of urinary liver fatty-acid-binding protein (L-FABP) as an early biomarker for AKI in children undergoing CPB surgery. METHODS: This is a case-control study of children undergoing CPB. AKI was defined as 50 % increase in serum creatinine at 48 h after surgery. For each patient, five serum and urine samples were obtained corresponding to time 0 h (presurgery) and 2, 6, 24, and 48 h after surgery. RESULTS: Twenty-seven patients, median age 360 days, were enrolled. AKI developed in 11 patients (41 %); three needed renal replacement therapy (peritoneal dialysis); there were two deaths. There were significant differences between patients with and without AKI in L-FABP levels at 2, 6, and 48 h after surgery, length of hospital stay, and CPB time; there were no differences in gender, patient age, and body weight. L-FABP was normalized to urinary creatinine concentration at all time points, with area under the receiver operator curve (AUC ROC) 0.867 at 2 and 6 h postoperatively. Correlation coefficient between L-FABP and length of hospital stay after surgery was statistically significant (r = 0.722, p value = 0.000). CONCLUSIONS: Our results suggest that urinary L-FABP can be used to diagnose AKI earlier than rise in serum creatinine in children undergoing CPB.

Age-related role of ambulatory electrocardiographic monitoring in risk stratification of patients with complete congenital atrioventricular block.

AIMS: The aim of the paper was to assess the importance of 24 h electrocardiographic Holter monitoring in determining predictive factors for Adams-Stokes (AS) attacks and heart failure (HF) in children and adolescents with complete congenital atrioventricular block (CCAVB). METHODS AND RESULTS: Forty-five patients were divided into two groups according to the presence of AS attacks and HF and six age-related subgroups. The following parameters of 24 h electrocardiographic Holter monitoring were analysed: (i) minimum heart rate (HR), (ii) maximum HR, (iii) average HR, (iv) daytime HR (v) rhythm and conduction disturbance. Adams-Stokes attacks and HF occurred in 10 and 8 patients, respectively (40%). Five of six neonates with HF had maximum HR < 74 bpm and daytime HR < 58 bpm. Maximum HR below 68 bpm and daytime HR below 52 bpm were recorded in all the children up to 8 years of age with AS attacks and HF and only in 3 of 14 asymptomatic patients. All the patients above 8 years of age with AS attacks had maximum HR below 62 bpm. Of 6 patients with daytime HR < 50 bpm AS attacks were present in two. Episodes of marked ventricular slowing during sleep were registered in 4 of 10 (40%) patients and in 3 of 27 (11%) symptomless patients. CONCLUSION: Risk factors for development of AS attacks and HF in patients with CCAVB include: (i) maximum HR < 74 bpm in neonates, <68 bpm up to the age of 8 and <62 bpm at ages above 8, (ii) daytime HR <58 bpm in neonates and < 52 bpm till the age of 8, and (iiii) abrupt pauses in ventricular rate that are at least twice the basic cycle length after the neonatal period.

Echocardiographic analysis of the subtypes of right ventricular restrictive physiology in surgically treated patients with tetralogy of Fallot.

BACKGROUND: Our study focuses on echocardiographic assessment of the right ventricular diastolic function and adaptive right ventricular response to volume overload resulting from pulmonary and tricuspid regurgitation in surgically treated patients with tetralogy of Fallot. METHOD AND RESULTS: We included 60 patients subsequent to surgical correction of tetralogy of Fallot, dividing them into two groups - a group of 18 patients with restrictive physiology, having antegrade flow to the pulmonary arteries greater than 30 centimetres per second in late diastole in five consecutive beats, and a group of 42 patients with non-restrictive physiology. Based on the cardiothoracic ratio, being more or equal to, or less than 0.55, we further divided those with restrictive physiology into a group of 14 patients deemed to have primary restriction, and the other 4 patients considered to have secondary or acquired restriction. Those with non-restrictive physiology were divided into groups of 16 patients with a small heart, and 26 patients with a large heart. A fraction of the venous retrograde diastolic flow in the hepatic vein greater or equal to 30 centimetres is important for distinguishing between the subgroup with primary restriction and the other subgroups. In the four patients with secondary restriction, anterograde diastolic flow in the pulmonary artery greater than 30 centimetres per second was recorded after the average period of follow-up of 2.4 years. The mean value of the pulmonary regurgitant jet pressure half-time was higher in the subgroup with the secondary restriction in comparison to the nonrestrictive subgroup with large hearts at 152 milliseconds with standard deviation of 36 milliseconds versus 85 milliseconds with standard deviation of 11 milliseconds, p less than 0.05. This was significantly lower in comparison to those with primary restriction, where the value was 238 milliseconds, with standard deviation of 42 milliseconds, p less than 0.02. CONCLUSION: Echocardiographic analysis offers great possibilities for assessment of right ventricular diastolic function, identifying in particular those with restrictive physiology, its interrelation with pulmonary and tricuspid regurgitation, as well as timing and selection of patients for re-intervention.