A NUMERICAL SIMULATION OF RED BLOOD CELL DISTRIBUTION IN A STENOSED MICROVESSEL USING IMMERSED BOUNDARY METHODS

2019 ◽  
Vol 24 (2) ◽  
pp. 108-113
Author(s):  
Daegeun Yoon ◽  
Donghyun You
2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Z. Hashemi ◽  
M. Rahnama ◽  
S. Jafari

In this paper, an attempt has been made to study sedimentation of a red blood cell (RBC) in a plasma-filled tube numerically. Such behaviors are studied for a healthy and a defective cell which might be created due to human diseases, such as diabetes, sickle-cell anemia, and hereditary spherocytosis. Flow-induced deformation of RBC is obtained using finite-element method (FEM), while flow and fluid–membrane interaction are handled using lattice Boltzmann (LB) and immersed boundary methods (IBMs), respectively. The effects of RBC properties as well as its geometry and orientation on its sedimentation rate are investigated and discussed. The results show that decreasing frontal area of an RBC and/or increasing tube diameter results in a faster settling. Comparison of healthy and diabetic cells reveals that less cell deformability leads to slower settling. The simulation results show that the sicklelike and spherelike RBCs have lower settling velocity as compared with a biconcave discoid cell.


2021 ◽  
Vol 10 (2) ◽  
pp. 286
Author(s):  
Angelo Zinellu ◽  
Arduino A. Mangoni

The identification of biomarkers predicting disease severity and outcomes is the focus of intense research in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 infection). Ideally, such biomarkers should be easily derivable from routine tests. We conducted a systematic review and meta-analysis of the predictive role of the red blood cell distribution width (RDW), a routine hematological test, in patients with SARS-CoV-2 infection. We searched the electronic databases PubMed, Web of Science and Scopus, from January 2020 to November 2020, for studies reporting data on the RDW and coronavirus disease 2019 (COVID-19) severity, defined as severe illness or admission to the intensive care unit (ICU), and mortality. Eleven studies in 4901 COVID-19 patients were selected for the meta-analysis. Pooled results showed that the RDW values were significantly higher in patients with severe disease and non-survivors (standard mean difference, SMD = 0.56, 95% CI 0.31 to 0.81, p < 0.001). Heterogeneity between studies was extreme (I2 = 80.6%; p < 0.001). In sensitivity analysis, the effect size was not modified when each study was in turn removed (effect size range, between 0.47 and 0.63). The Begg’s (p = 0.53) and Egger’s tests (p = 0.52) showed no evidence of publication bias. No significant correlations were observed between SMD and age, gender, whole blood count, end point, study geographic area, or design. Our meta-analysis showed that higher RDW values are significantly associated with COVID-19 severity and mortality. This routine parameter might assist with early risk stratification in patients with SARS-CoV-2 infection.


2013 ◽  
Vol 275 (1) ◽  
pp. 84-92 ◽  
Author(s):  
S. Adamsson Eryd ◽  
Y. Borné ◽  
O. Melander ◽  
M. Persson ◽  
J. G. Smith ◽  
...  

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