Ece Salihoglu

We aimed to build a fuzzy logic preanaesthetic risk score tailored to cataract surgery. By fusing systemic comorbidities with key patient attributes in an adaptive rule base, our goal was to generate patient-specific risk estimates that move beyond the coarse granularity of traditional categorical tools. A prospective observational cohort study was conducted at Kanuni Sultan Suleyman Hospital, University of Health Sciences, Istanbul, Turkey. Two hundred fifty-one adults who were scheduled for cataract surgery under either local or general anesthesia were included in the study. Demographic information and comorbidities were gathered prior to surgery. A fuzzy inference system incorporating 5 major (pulmonary, cardiac, renal, liver disease, and diabetes) and 3 minor (age, BMI, and smoking) criteria was developed. Risk levels were generated using 270 expert-defined fuzzy rules. Postoperative transient intraocular pressure (IOP) elevations and other complications were monitored. Among the 251 patients, 70 (27.9%) developed postoperative transient IOP elevations. Fuzzy risk scores correlated strongly with the number of major comorbidities ( r = 0.954), confirming internal consistency. However, the model did not significantly differentiate between patients with and without postoperative transient intraocular pressure (IOP) elevations (AUC = 0.439; P > .05). There were no other complications found, but transient IOP elevations was significantly linked to advanced age and long-term smoking. The fuzzy logic model reliably quantified systemic risk burden but lacked predictive power for ophthalmic-specific outcomes driven by ocular factors such as transient IOP elevations. Incorporating domain-specific variables like intraocular pressure and detailed ophthalmologic assessments may improve future performance. The model remains valuable for general preanesthetic risk stratification in surgical populations.

Objectives: This article aims to explain the altered oxidative status and thiol/disulfide homeostasis before and after surgery in children with congenital heart disease (CHD). Methods: Blood samples were taken from the patients (n=50) before the operation (baseline), at the 1st hour, and at the 24th hour after the operation. Thiol-disulfide levels, total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), myeloperoxidase (MPO), ceruloplasmin, albumin, ischemia-modified albumin (IMA), and prolidase activities of all samples were measured. Pre-operative oxygen saturation (SaO ₂ ) values and neutrophil/lymphocyte ratios (NLR) were also measured. Results: Before the operation, TOS, OSI, MPO, ceruloplasmin, IMA, NRL, and disulfide levels were higher in the cyanotic group than in the acyanotic group. When the indicated three different time points were compared, the TOS, OSI levels, and MPO activities of the 24th hour were significantly lower than the baseline and 1st hour. In comparison, ceruloplasmin levels of 1st hour were significantly higher than of the baseline and 24th hour. Native thiol and total thiol levels in the baseline group were significantly lower than in the 1st and 24th hours. Disulfide levels of the 24th hour were significantly lower than of the baseline. Conclusions: The operation leads to changes in the thiol-disulfide balance and oxidant status in CHD.

Objective: Malposition of dual lumen cannula is a frequent and challenging complication in neonates and plays a significant role in shaping the in vitro device hemodynamics. This study aims to analyze the effect of the dual lumen cannula malposition on right-atrial hemodynamics in neonatal patients using an experimentally validated computational fluid dynamics model. Methods: A computer model was developed for clinically approved dual lumen cannula (13Fr Origen Biomedical, Austin, Texas, USA) oriented inside the atrium of a 3-kg neonate with normal venous return. Atrial hemodynamics and dual lumen cannula malposition were systematically simulated for two rotations (antero-atrial and atrio-septal) and four translations (two intravascular movements along inferior vena cava and two dislodged configurations in the atrium). A multi-domain compartmentalized mesh was prepared to allow the site-specific evaluation of important hemodynamic parameters. Transport of each blood stream, blood damage levels, and recirculation times are quantified and compared to dual lumen cannula in proper position. Results: High recirculation levels (39 ± 4%) in malpositioned cases resulted in poor oxygen saturation where maximum recirculation of up to 42% was observed. Apparently, Origen dual lumen cannula showed poor inferior vena cava blood–capturing efficiency (48 ± 8%) but high superior vena cava blood–capturing efficiency (86 ± 10%). Dual lumen cannula malposition resulted in corresponding changes in residence time (1.7 ± 0.5 seconds through the tricuspid). No significant differences in blood damage were observed among the simulated cases compared to normal orientation. Compared to the correct dual lumen cannula position, both rotational and translational displacements of the dual lumen cannula resulted in significant hemodynamic differences. Conclusion: Rotational or translational movement of dual lumen cannula is the determining factor for atrial hemodynamics, venous capturing efficiency, blood residence time, and oxygenated blood delivery. Results obtained through computational fluid dynamics methodology can provide valuable foresight in assessing the performance of the dual lumen cannula in patient-specific configurations.

Objective: Two-stage arterial switch operation and left ventricle retraining are necessary for the patients with left ventricle dysfunction and transposition of great vessels with intact ventricular septum (TGA-IVS) who are referred late.Material and methods: Forty-seven patients with the diagnosis of TGA-IVS and left ventricle dysfunction who underwent arterial switch operation in our centre between July 2013 and August 2017 were analysed retrospectively. The inclusion criteria for left ventricle retraining were patients older than 2 months of age at presentation, having an echocardiographic left ventricle mass index of less than 35 g/m², and having an echocardiographic “banana-shaped” left ventricle geometric appearance. The patients were divided into two groups: pulmonary artery banding and Blalock Taussig shunt were performed as the initial surgical procedure for later arterial switch operation in Group I (n = 19) and pulmonary artery banding and bidirectional cava-pulmonary shunt in Group 2 (n = 28).Results: The average age was found to be 122.3 ± 45.6 days in Group I and 145.9 ± 37.2 days in Group II. There was no statistically significant difference (p = 0.232 versus p = 0.373) between the average left ventricle mass index of the two groups neither before the first stage nor the second stage (26.6 ± 4.8 g/m² versus 25.0 ± 4.9 g/m² and 70.5 ± 12 g/m² versus 673.8 ± 12.0 g/m², respectively). The average time interval for the left ventricle to retrain was 97.7 ± 42.9 days for Group I and 117.3 ± 40.3 days for Group II, significantly lower in Group I (p = 0.027). The time spent in ICU, length of the period during which inotropic support was required, and the duration of hospital stay were significantly higher in Group I (p<0.001, p < 0.001, and p < 0.00, respectively).Conclusion: Pulmonary artery banding and bidirectional cava-pulmonary shunt can be performed as a safe and effective alternative to pulmonary artery banding and arterial Blalock Taussig shunt for patients with TGA-IVS in whom arterial switch operation is needed beyond the neonatal period. This approach involves a shorter hospital stay and fewer post-operative complications.

Objective: Determination of preanesthetic high risk during surgical procedures using fuzzy risk evaluation. Material and Methods: In this study for the high risk patient classification, five major criteria comprising cardiac, pulmonary, renal or liver diseases and diabetes mellitus and three minor criteria comprising patients' age, body mass index and cigarette smoking were chosen to define the high-risk group. Since the fuzzy logic gives the ability to use linguistic expressions, that include the intuition of human operators or experts during the decision making process, it this study by using fuzzy logic modelling, rules for high risks were developed. To reach this aim a new fuzzy logic decision system is proposed that uses four input variables to calculate the risk as a percentage that is the output of the fuzzy system. Results: Using Fuzzy risk evaluation; By taking into account the number of inputs and number of their corresponding membership functions, it is deduced that 270 fuzzy rules will be enough. Conclusion: In this study, a risk classification model was developed by combining the risk criteria defined by previous medical studies and clinical experience with a fuzzy logic model in the preoperative period. This developed fuzzy logic model needs to be investigated by selecting specific groups of patients and specific operations.

Surgical treatment of congenital heart disease (CHD) involves complex vascular reconstructions utilizing artificial and native surgical materials. A successful surgical reconstruction achieves an optimal hemodynamic profile through the graft in spite of the complex post-operative vessel growth pattern and the altered pressure loading. This paper proposes a new in silico patient-specific pre-surgical planning framework for patch reconstruction and investigates its computational feasibility. The proposed protocol is applied to the patch repair of main pulmonary artery (MPA) stenosis in the Tetralogy of Fallot CHD template. The effects of stenosis grade, the three-dimensional (3D) shape of the surgical incision and material properties of the artificial patch are investigated. The release of residual stresses due to the surgical incision and the extra opening of the incision gap for patch implantation are simulated through a quasi-static finite-element vascular model with shell elements. Implantation of different unloaded patch shapes is simulated. The patched PA configuration is pressurized to the physiological post-operative blood pressure levels of 25 and 45 mmHg and the consequent post-operative stress distributions and patched artery shapes are computed. Stress–strain data obtained in-house, through the biaxial tensile tests for the mechanical properties of common surgical patch materials, Dacron, Polytetrafluoroethylene, human pericardium and porcine xenopericardium, are employed to represent the mechanical behavior of the patch material. Finite-element model is experimentally validated through the actual patch surgery reconstructions performed on the 3D printed anatomical stenosis replicas. The post-operative recovery of the initially narrowed lumen area and post-op tortuosity are quantified for all modeled cases. A computational fluid dynamics solver is used to evaluate post-operative pressure drop through the patch-reconstructed outflow tract. According to our findings, the shorter incisions made at the throat result in relatively low local peak stress values compared to other patch design alternatives. Longer cut and double patch cases are the most effective in repairing the initial stenosis level. After the patch insertion, the pressure drop in the artery due to blood flow decreases from 9.8 to 1.35 mmHg in the conventional surgical configuration. These results are in line with the clinical experience where a pressure gradient at or above 50 mmHg through the MPA can be an indication to intervene. The main strength of the proposed pre-surgical planning framework is its capability to predict the intra-operative and post-operative 3D vascular shape changes due to intramural pressure, cut length and configuration, for both artificial and native patch materials.

Clinical success of pediatric veno‐venous (VV) extracorporeal membrane oxygenation (ECMO) is associated with the double lumen cannula cardiovascular device design as well as its anatomic orientation in the atrium. The positions of cannula ports with respect to the vena cavae and the tricuspid valve are believed to play a significant role on device hemodynamics. Despite various improvements in ECMO catheters, especially for the neonatal and congenital heart patients, it is still challenging to select a catalogue size that would fit to most patients optimally. In effect, the local unfavorable blood flow characteristics of the cannula would translate to an overall loss of efficiency of the ECMO circuit. In this study, the complex flow regime of a neonatal double lumen cannula, positioned in a patient‐specific right atrium, is presented for the first time in literature. A pulsatile computational fluid dynamics (CFD) solver that is validated for cardiovascular device flow regimes was used to perform the detailed flow, oxygenated blood transport, and site‐specific blood damage analysis using an integrated cannula and right atrium model. A standard 13Fr double lumen cannula was scanned using micro‐CT, reconstructed and simulated under physiologic flow conditions. User defined scalar transport equations allowed the quantification of the mixing and convection of oxygenated and deoxygenated blood as well as blood residence times and hemolysis build‐up. Site‐specific CFD analysis provided key insight into the hemodynamic challenges encountered in cannula design and the associated intra‐atrial flow patterns. Due to neonatal flow conditions, an ultra high velocity infusion jet emanated from the infusion port and created a zone of major recirculation in the atrium. This flow regime influenced the delivery of the oxygenated blood to the tricuspid valve. Elevated velocities and complex gradients resulted in higher wall shear stresses (WSS) particularly at the infusion port having the highest value followed by the aspiration hole closest to the drainage port. Our results show that, in a cannula that is perfectly oriented in the atrium, almost 38% of the oxygenated blood is lost to the atrial circulation while only half of the blood from inferior vena cava (IVC) can reach to the tricuspid valve. As such, approximately 6% of venous blood from superior vena cava (SVC) can be delivered to tricuspid. High values of hemolysis index were observed with blood damage encountered around infusion hole (0.025%). These results warrant further improvements in the cannula design to achieve optimal performance of ECMO and better patient outcomes.