Evaluation of antithrombotic prophylaxis and thrombotic events in children with COVID-19 or MIS-C: A tertiary pediatric center experience.

OBJECTIVES: COVID-19 and multisystem inflammatory syndrome in children (MIS-C) are associated with a risk of hypercoagulability and thrombotic events. We aimed (a) to evaluate the demographic, clinical, and laboratory findings as well as the incidence of thrombotic events of COVID-19 and MIS-C in children and (b) to determine the role of antithrombotic prophylaxis. METHODS: A single-center retrospective study evaluated hospitalized children with COVID-19 or MIS-C. RESULTS: The study group consisted of 690 patients, 596 (86.4%) diagnosed with COVID-19 and 94 (13.6%) diagnosed with MIS-C. Antithrombotic prophylaxis was used for 154 (22.3%) patients: 63 patients (10.6%) in the COVID-19 group and 91 (96.8%) patients in the MIS-C group. Use of antithrombotic prophylaxis was statistically higher in the MIS-C group (p<0.001). Patients who received antithrombotic prophylaxis were of older median age, were more commonly male, and had more frequent underlying diseases than those without prophylaxis (p<0.001, p<0.012, p<0.019, respectively). The most common underlying condition was obesity in patients who received antithrombotic prophylaxis. Thrombosis was observed in one (0.2%) patient in the COVID-19 group with a thrombus in the cephalic vein, two (2.1%) patients in the MIS-C group, with a dural thrombus in one patient and a cardiac thrombus in the other patient. The patients with thrombotic events were previously healthy and had mild disease. CONCLUSION: In our study, thrombotic events were rare compared with previous reports. We used antithrombotic prophylaxis for most children with underlying risk factors; perhaps for this reason, we did not observe thrombotic events in children with underlying risk factors. We suggest that patients diagnosed with COVID-19 or MIS-C be closely monitored for thrombotic events.

Improving the sludge disintegration efficiency of sonication by combining with alkalization and thermal pre-treatment methods.

One of the most serious problems encountered in biological wastewater treatment processes is the production of waste activated sludge (WAS). Sonication, which is an energy-intensive process, is the most powerful sludge pre-treatment method. Due to lack of information about the combined pre-treatment methods of sonication, the combined pre-treatment methods were investigated and it was aimed to improve the disintegration efficiency of sonication by combining sonication with alkalization and thermal pre-treatment methods in this study. The process performances were evaluated based on the quantities of increases in soluble chemical oxygen demand (COD), protein and carbohydrate. The releases of soluble COD, carbohydrate and protein by the combined methods were higher than those by sonication, alkalization and thermal pre-treatment alone. Degrees of sludge disintegration in various options of sonication were in the following descending order: sono-alkalization > sono-thermal pre-treatment > sonication. Therefore, it was determined that combining sonication with alkalization significantly improved the sludge disintegration and decreased the required energy to reach the same yield by sonication. In addition, effects on sludge settleability and dewaterability and kinetic mathematical modelling of pre-treatment performances of these methods were investigated. It was proven that the proposed model accurately predicted the efficiencies of ultrasonic pre-treatment methods.