Objective and Background In Japan, an increase in the elderly population is associated with an increased incidence of aspiration pneumonia.

Coronavirus disease (COVID-19)-related systemic cytokine response induces the production of procoagulant factors, which predisposes patients to a prothrombotic state. Viscoelastic testing can identify the degree of hypercoagulability, which is related to outcomes. We aimed to study the changes in clot waveform analysis (CWA) parameters in COVID-19 patients on hospital admission compared to those in a group of healthy individuals. We conducted a retrospective study of COVID-19 patients admitted to general wards and evaluated demographic and clinical parameters as well as laboratory parameters, including coagulation parameters. CWA data from patients (n = 62) with COVID-19 prior to the initiation of anticoagulation therapy were compared with those from healthy controls (n = 67). The measured CWA parameters were min1, min2, max2, and delta change. CWA, fibrinogen, and D-dimer values were higher in COVID-19 patients than in healthy controls (p < 0.001). CWA profiles were consistent with hypercoagulability and characterized by an increase in density, velocity, and acceleration of clot formation. Activated partial thromboplastin time, fibrinogen, D-dimer, and C-reactive protein (CRP) values were higher in patients in whom all CWA parameters were raised than in patients with just a few elevated CWA parameters, while Sequential Organ Failure Assessment scores, prothrombin time, fibrin degradation product levels and platelet counts did not differ between the two groups. CWA variables showed hypercoagulopathy on admission in COVID-19 patients who were hospitalized in the general ward, and this pattern was more pronounced in critically ill patients with elevated fibrinogen, D-dimer, and CRP levels. Our results may help identify patients at high risk of thromboembolism. Keywords COVID-19 • General ward • Clot wave analysis • Hypercoagulability • Fibrinogen Abbreviations CWA Clot wave analysis aPTT Activated partial thromboplastin time CRP C-reactive protein VTE Venous thromboembolic event DIC Disseminated intravascular coagulation, BMI Body mass index SOFA Sequential Organ Failure Assessment PT Prothrombin time Highlights• CWA can provide more precise information regarding alterations in fibrin clot properties, which might represent risk factors for VTE, than fibrinogen assays. • CWA is an economically convenient and simple test that can aid clinical stratification and management by implementing an algorithm into the software of an automated coagulometer.

This in vitro study evaluated the potential hemostatic effect of fresh frozen plasma (FFP) ultrafiltration on clotting factors, coagulation parameters, and plasma properties. ABO-specific units of FFP (n = 40) were prepared for the concentrated FFP and cryoprecipitate. Plasma water was removed from FFP by ultrafiltration using a dialyzer with a pump running at a 300 ml/min. The aliquot of each concentrated FFP after 50, 100, 200, and 250 ml of fluid removal were served for the standard coagulation assay, measurement of clotting activity, and plasma properties to compare those parameters of cryoprecipitate. Concentrated FFP contained 36.5% of fibrinogen in FFP with a mean concentration of 7.2 g/L, lower than the cryoprecipitate level. The levels of factor Ⅷ (FⅧ), von Willebrand factor (vWF): antigen (Ag), and vWF: ristocetin cofactor (Rco) were also lower in concentrated FFP, whereas the levels of factor Ⅴ, factor Ⅸ, factor ⅩⅢ, antithrombin and albumin was higher in concentrated FFP. Maximum clot firmness (MCF) in thromboelastometry was approximately one-half of that in cryoprecipitate. Although the levels of vWF: Ag, vWF: Rco, and FⅧ differed depending on the ABO blood types, fibrinogen levels, and MCF were not significantly different among the ABO blood groups in FFP and concentrated FFP.