The effects of protamine sulfate on clot formation time and clot strength thromboelastography variables for canine blood samples

2014 ◽  
Vol 75 (4) ◽  
pp. 338-343 ◽  
Author(s):  
Christopher J. Bailey ◽  
Amy M. Koenigshof
2021 ◽  
Vol 10 (15) ◽  
pp. 3397
Author(s):  
Andreas G. Tsantes ◽  
Dimitrios V. Papadopoulos ◽  
Ioannis G. Trikoupis ◽  
Stavros Goumenos ◽  
Daniele Piovani ◽  
...  

Introduction: Coronavirus disease 2019 (COVID-19) in patients with hip fractures is associated with increased incidence of venous thromboembolism (VTE). The purpose of this study was to evaluate the hemostatic alterations of COVID-19 that are associated with a higher thrombotic risk using rotational thromboelastometry (ROTEM). Methods: A retrospective observational study was performed including 20 COVID-19 patients with hip fractures. To compare the coagulopathy of patients with mild COVID-19 and hip fractures with the coagulopathy associated with each of these two conditions separately, we used two previously recruited groups of patients; 198 hip fracture patients without COVID-19 and 21 COVID-19 patients without hip fractures. The demographics, clinical parameters, conventional coagulation parameters and ROTEM findings of the three groups were analyzed and compared. Results: COVID-19 hip fracture patients had higher amplitude of clot firmness at 10 min (p < 0.001), higher alpha angle (p < 0.001), higher lysis index at 60 min (p < 0.001), and shorter clot formation time (p < 0.001) than non-COVID-19 hip fracture patients, indicating increased clot strength and impaired fibrinolysis due to COVID-19. The value of lysis index at 60 min (99%) in COVID-19 patients with hip fractures was consistent with fibrinolysis shut down. Multivariable linear regression analysis further confirmed that COVID-19 resulted in increased amplitude of clot firmness at 10 min (p < 0.001), increased maximum clot firmness (p < 0.001), increased lysis index at 60 min (p < 0.001) and increased alpha angle (p < 0.001), but significantly shortened clot formation time (p < 0.001). Discussion: The higher thrombotic risk in COVID-19 patients with hip fractures is characterized by increased clot strength and fibrinolysis shutdown, as shown by ROTEM findings. Further prospective studies are warranted to evaluate the need for modification of thromboprophylaxis to balance the hemostatic derangements of COVID-19 patients with hip fractures.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Daishen Luo ◽  
Damir Khismatullin ◽  
R. Glynn Holt

Background: Critical care patients such as trauma and major surgery patients often develop coagulopathy due to depletion of both pro- and anti-coagulants. They are at high risk of both bleeding and thrombotic complications and require monitoring of their coagulation status. The contact of a blood sample with artificial surfaces and its exposure to clot activators, which happen in all commercially available coagulation analyzers, may lead to improper assessment of blood coagulation and thus errors in predicting bleeding/thrombosis risks. Objective: Real-time assessment of whole blood or blood plasma coagulation by novel non-contact acoustic tweezing technology. Method: 4-5 microliter drops of whole blood collected from healthy volunteers or commercial control plasma were levitated in air by acoustic radiation forces. Their coagulation kinetics including reaction time, fibrin network formation time (FNFT), clot formation time and maximum clot strength was assessed from mechanical (drop shape) and photo-optical (light intensity) data. FNFT was determined as a difference between mechanical and photo-optical reaction times. Results: Whole blood samples were exposed to pro- or anti-coagulants during levitation in the acoustic tweezing device. Changes in the coagulation status between different experimental groups were detected within 10 minutes. Similarly, less than 7 minutes was required to detect significant changes in reaction time, clot formation time and maximum clot strength between low, normal, and high fibrinogen level control plasma samples. FNFT was shown to be significantly reduced in plasma samples with a higher level of Factor XIII. Conclusions: The acoustic tweezing technology integrates photo-optical tests used in plasma coagulation assays with viscoelastic tests used in whole blood analysis. Its key disruptive features are the increased reliability and accuracy due to non-contact measurement, small sample volume requirement, relatively short procedure time (<10 minutes), and the ability to assess the level of Factor XIII function from FNFT measurements. Our technology addresses a current lack of reliable methods to measure blood coagulation in patients with coagulopathy.


2018 ◽  
Vol 46 (3) ◽  
pp. 272-277 ◽  
Author(s):  
P. C. A. Kam ◽  
S. Varanasi ◽  
K. X. Yang

We investigated the in vitro viscoelastic changes of progressive haemodilution with succinylated gelatin (SG) solution compared with normal saline (NS) using rotational thromboelastometry (ROTEM®). Whole blood (WB) samples obtained from 20 healthy volunteers were diluted in vitro with SG solution or NS by 10%, 20% and 40%. Fibrinogen concentration and ROTEM (EXTEM, FIBTEM) variables including coagulation time (CT), clot formation time (CFT), α-angle, and maximum clot firmness (MCF) were measured in the undiluted sample and at each degree of haemodilution. Haemodilution with SG decreased FIBTEM MCF by 34.8% at 20% dilution (SG 20% haemodilution mean 9.1 [standard deviation, SD 2.7] mm versus WB, mean 13.9 [SD 3.4] mm) whereas this was observed only at 40% haemodilution with NS (mean 8.5 [SD 2.7] mm, 38.7% decrease). We found that 40% haemodilution with SG slowed clot formation (EXTEM CFT; SG 40%, mean 179 [SD 39] seconds versus WB mean 87.9 [SD 13.7] seconds; increased CFT by 103%), reduced clot strength by 23.5% (EXTEM MCF; SG 40% mean 47.7 [SD 3.4] mm versus WB mean 62.4 [SD 2.5] mm), and decreased fibrin formation (FIBTEM MCF; SG 40% mean 5.8 [SD 1.6] mm versus WB mean 13.9 [SD 3.4] mm); 58.4% decrease). The platelet contribution to clot strength (EXTEM MCF–FIBTEM MCF) was not changed by SG. We found that haemodilution of more than 20% with SG impaired coagulation greater than that observed with NS haemodilution in this in vitro study. This suggests that at 40% haemodilution with SG, a clinical scenario that could occur during resuscitation of a patient in grade IV haemorrhagic shock, impaired coagulation could occur. Frequent monitoring of coagulation is advised when SG solutions are administered rapidly during volume resuscitation.


2018 ◽  
Vol 21 (8) ◽  
pp. 708-713 ◽  
Author(s):  
Duree Shin ◽  
Aryung Nam ◽  
Kun Ho Song ◽  
Kyoung Won Seo

Objectives The aim of this study was to evaluate the effect of two differently sized butterfly catheter needles and the effect of venepuncture difficulty on thromboelastography (TEG) results in healthy cats. Methods Twenty-four healthy cats were included. Blood samples were collected from the jugular vein by syringe aspiration via direct venepuncture with 21 G and 22 G butterfly needles. The venepuncture difficulty score was classified into four categories. The first 1.5 ml blood drawn from each subject was discarded before collecting a sample for TEG analysis. TEG analyses were performed on citrated whole blood samples from 17 clinically healthy cats, using assays with kaolin as activators. Among the TEG parameters, reaction time (R), clot formation time (κ), alpha angle (α), maximum amplitude (MA) and global clot strength (G) were recorded from each tracing. Results Seven cats were excluded from the study; results were obtained for the remaining 17 cats. There were no statistically significant differences between the use of two different needles for R ( P = 0.72), κ ( P = 0.74), α ( P = 0.99), MA ( P = 0.08) and G ( P = 0.09). Samples with difficulty scores ⩾1 were not significantly different from samples with difficulty scores of 0 for R ( P = 0.24), κ ( P = 0.65), α ( P = 0.65), MA ( P = 0.72) and G ( P = 0.77). Conclusions and relevance The results of TEG in clinically healthy cats do not differ significantly when using two different gauge needles. There was no significant difference in the TEG results according to venepuncture difficulty scoring.


2017 ◽  
Vol 45 (5) ◽  
pp. 562-568 ◽  
Author(s):  
P. C. A. Kam ◽  
J. P. C. Liou ◽  
K. X. F. Yang

We evaluated the effects of haemodilution with either dextran 40 or 0.9% normal saline on coagulation in vitro using rotational thromboelastometry (ROTEM®, Pentapharm Co., Munich, Germany) and multiple electrode aggregometry (Multiplate® Platelet Function Analyser, Dynabyte, Munich, Germany). Venous blood samples obtained from 20 healthy volunteers were diluted in vitro with dextran 40 or normal saline by 5%, 10% and 15%. Fibrinogen concentration, ROTEM-EXTEM® (screening test for the extrinsic coagulation pathway), FIBTEM® (an EXTEM-based assay of the fibrin component of clot) parameters including coagulation time, clot formation time, alpha angle, maximum clot firmness and lysis index were measured in the undiluted sample and at each level of haemodilution. Dextran 40 at 15% haemodilution significantly prolonged coagulation time, clot formation time and significantly decreased the alpha angle and maximal clot firmness (EXTEM amplitude at five minutes [A5] and ten minutes [A10]) compared with normal saline. The FIBTEM assay (maximal clot firmness and FIBTEM A5 and A10) showed a marked decrease in maximal clot firmness at all dilutions suggesting impaired fibrinogen activity and a risk of bleeding. Multiple electrode aggregometry did not demonstrate any platelet dysfunction. Haemodilution with dextran 40 causes significant impairment in clot formation and strength compared to saline haemodilution and undiluted blood. At the levels of in vitro haemodilution designed to reflect the clinical use of dextran infusions, no significant fibrinolysis or platelet inhibition was observed.


2014 ◽  
Vol 307 (5) ◽  
pp. L347-L354 ◽  
Author(s):  
Sotirios G. Zarogiannis ◽  
Brant M. Wagener ◽  
Susanna Basappa ◽  
Stephen Doran ◽  
Cilina A. Rodriguez ◽  
...  

Chlorine (Cl2) is a highly reactive oxidant gas that, when inhaled, may cause acute lung injury culminating in death from respiratory failure. In this study, we tested the hypothesis that exposure of mice to Cl2causes intra-alveolar and systemic activation of the coagulation cascade that plays an important role in development of lung injury. C57Bl/6 mice were exposed to Cl2(400 for 30 min or 600 ppm for 45 min) in environmental chambers and then returned to room air for 1 or 6 h. Native coagulation (NATEM) parameters such as blood clotting time and clot formation time were measured in whole blood by the viscoelastic technique. D-dimers and thrombin-anti-thrombin complexes were measured in both plasma and bronchoalveolar lavage fluid (BALF) by ELISA. Our results indicate that mice exposed to Cl2gas had significantly increased clotting time, clot formation time, and D-dimers compared with controls. The thrombin-anti-thrombin complexes were also increased in the BALF of Cl2exposed animals. To test whether increased coagulation contributed to the development of acute lung injury, mice exposed to Cl2and returned to room air were treated with aerosolized heparin or vehicle for 20 min. Aerosolized heparin significantly reduced protein levels and the number of inflammatory cells in the BALF at 6 h postexposure. These findings highlight the importance of coagulation abnormities in the development of Cl2-induced lung injury.


2020 ◽  
Author(s):  
Brian O’Rourke ◽  
Sunny Nguyen ◽  
Arno W. Tilles ◽  
James A. Bynum ◽  
Andrew P Cap ◽  
...  

AbstractWhile mesenchymal stromal cells (MSCs) are an appealing therapeutic option for a range of clinical applications, their potential to induce clotting when used systemically remains a safety concern, particularly in hypercoagulable conditions, such as in patients with severe COVID-19, trauma, or cancers. Here, we tested a novel ex vivo approach aimed at improving the safety of MSC systemic administration by use of a bioreactor. In this device, MSCs are seeded on the outside of a hollow-fiber filter, sequestering them behind a hemocompatible membrane, while still maintaining cross talk with blood cells and circulating signaling molecules. The potential for these bioreactor MSCs to induce clots in coagulable plasma was compared against “free” MSCs, as a model of systemic administration, which were directly injected into the circuit. Our results showed that physical isolation of the MSCs via a bioreactor extends the time necessary for clot formation to occur when compared to “free” MSCs. Measurement of cell surface data indicates the presence of known clot inducing factors, namely tissue factor and phosphatidylserine. Results also showed that recovering cells and flushing the bioreactor prior to use further prolonged clot formation time. Further, application of this technology in two in vivo models did not require additional heparin to maintain target ACT levels relative to the acellular device. Taken together, the use of hollow fiber filters to house MSCs, if adopted clinically, could offer a novel method to control systemic MSC exposure and prolong clot formation time.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Mengyun Xiao ◽  
Stefanie Hammer ◽  
Wissam A Khalel ◽  
Lisann Pelzl ◽  
Bernhard N Bohnert ◽  
...  

Abstract Background and Aims Urinary excretion of the fibrinolytic enzyme plasminogen has been identified as a characteristic feature of nephrotic syndrome (NS) in both human and experimental mouse models. Lack of plasminogen may lead to a hypercoagulable state and thrombosis, and mice with plasminogen deficiency have been shown to suffer from developing spontaneous thrombosis. However, the role of plasminogen in hypercoagulable state and thrombosis in an experimental nephrotic syndrome has not been investigated before. Method We investigated the relationship between plasminogen and a hypercoagulable state in an inducible nephrotic mouse model with conditional podocyte-specific podocin deletion (Nphs2Δipod * Plg+/+, n=12). The Nphs2Δipod mice with constitutive plasminogen knockout were used as negative plasminogen control (Nphs2Δipod * Plg-/-, n=15). All mice received a daily oral doxycycline administration for 2 weeks for NS induction. The last day of doxycycline treatment was set as day 0. Spot urine was collected daily for proteinuria and urinary plasmin activity measurement. Citrate blood was collected from each mouse before induction of NS, 7 days and 21 days after induction, respectively (Nphs2Δipod * Plg+/+ mice, n=4/timepoint; Nphs2Δipod * Plg-/- mice, n=5/timepoint). A global assessment of coagulation (extrinsic coagulation test, EX test) was examined by ClotPro® system. Besides, fibrinolysis was tested by adding tissue plasminogen activator (TPA test). Results According to the EX test, uninduced mice with plasminogen deficiency showed a significantly reduced clotting time (CT, Plg-/- vs. Plg+/+, 42 ± 1s vs. 54 ± 4s, p=0.0213), and decreased clot formation time (CFT, Plg-/- vs. Plg+/+, 82 ± 5s vs. 206 ± 28s p&lt;0.0001) with a larger alpha-angle (Plg-/- vs. Plg+/+, 75 ± 1° vs. 66 ± 2°, p=0.0041). The maximum clot firmness (MCF) was significantly increased in uninduced plasminogen knockout mice (Plg-/- vs. Plg+/+, 45 ± 0.5mm vs. 32 ± 2.5mm p&lt;0.0001). According to the TPA test, uninduced Nphs2Δipod *Plg-/-mice had a faster velocity of clot formation (α-angle, 75.6 ± 0.2° vs. 66.5 ± 1.6°, p=0.0254) and did not show any clot lysis in contrast to uninduced nphs2Δipod * plg+/+mice. After induction of NS, both Nphs2Δipod * Plg-/-mice and Nphs2Δipod * Plg+/+ mice developed massive proteinuria to a comparable extent (Plg-/- vs. Plg+/+on day 21, 218 ± 46mg/mg crea vs. 203 ± 28mg/mg crea), and plasminuria was detectable in nephrotic nphs2Δipod * plg+/+ mice. With the ongoing loss of plasminogen in the urine, CT and CFT was significantly reduced in nephrotic Nphs2Δipod * Plg+/+ mice. MCF was significantly increased with a faster velocity of clot formation measured by both the EX and TPA test. Moreover, clot lysis was significantly reduced. In nephrotic nphs2Δipod *plg-/-mice at day 21, there was also a tendency towards a decrease in CT, CFT and an increased velocity of clot formation. According to both EX and TPA test, there were no significant differences between the genotypes in nephrotic mice any more. Conclusion The results highlight that loss of plasminogen in the nephrotic state contributes to a hypercoagulable state with shortened clotting time, clot formation time, increased clot firmness, and most strikingly, loss of clot lysis. Changes in nephrotic wild-type mice were similar to mice with constitutive plasminogen deficiency, indicating that loss of plasminogen plays a role in the hypercoagulable state of nephrotic syndrome.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3485-3485
Author(s):  
Donald Brophy ◽  
Erika Martin ◽  
John Christian Barrett ◽  
Mindy Nolte ◽  
Janice Kuhn ◽  
...  

Abstract Abstract 3485 Poster Board III-422 Introduction The clinical response of hemophilia patients with inhibitors to bypassing agent therapy can be unexpectedly poor. Indeed, there are reports of “poor responders” who either require alternative treatment or dose escalation. The lack of correlation between routine coagulation assays or factor antigen/activity levels with clinical efficacy contributes to the problem in these patients. Analysis of the clotting characteristics of “poor responders” is limited. In a recent study of rFVIIa PK in 10 non-bleeding hemophilia A and B patients, we noted that four of the ten had a remarkable attenuated response as seen in whole blood assays. We report here a comparison of clotting parameters in the “poor responders” versus robust responders to rFVIIa infusion, and attempt to define what might be the source of the altered response. Patients and Methods Ten severe FVIII or FIX deficient patients in a non-bleeding state were infused with a single-dose of rFVIIa (90 μg/kg). Platelet contractile force (PCF), clot structure (CEM,MA,MCF), and clot formation time (FOT,R,CT) were analyzed in whole blood by Hemodyne HAS, Thromboelastography, and Rotation Thromboelastography before, and at 0.5,1,2,4 and 6 hours following rFVIIa dosing. Thrombin generation parameters (Tlag, Cmax) were measured in PRP by the Calibrated Automated Thrombogram. Plasma concentrations of FVII:C and FVII:Ag were measured at each time point. Patients with a clot formation time (FOT, R, CT) ≥ 15 minutes following rFVIIa dosing were termed “Poor Responders”. Results There were few inter-group differences in baseline clotting characteristics. The values for all parameters are provided in Table 1. FVII PK were not different between the Responders and Poor-Responders. This can be appreciated from the PK parameters listed in the table as well as from relative lack of variability for the composite rFVIIa levels seen for the entire group of 10 patients (Figure 1, panels 1 and 2). Both groups had similar FVIIa Cmax and total body clearance values. However, the responders made significantly stronger clots (PCF, CEM) as can be appreciated in table 1 and even more dramatically in panels 3 and 4 of figure 1. In these panels, the responders and poor responders are plotted as separate groups. Even though the groups are small (n=6 vs 4) the minimal response (both in magnitude and duration) to rFVIIa in terms of platelet function (PCF) and clot structure (CEM) is grossly apparent. All three whole blood assays revealed significantly shorter time to clot formation (R, FOT, CT) in the responders. However, the MA (TEG) and MCF (ROTEG), and thrombin generation parameters (Tlag, max) failed to show significant inter-group differences following rFVIIa dosing. Conclusions These data suggest that the differences observed between Responders and Poor Responders are not due to PK influences, but may be related to differences in the effects of thrombin on platelet function. It is possible that whole blood assays may serve as a tool to monitor the clinical effects of rFVIIa. Changes in clot stiffness were better characterized by CEM compared to MA and MCF. There was good correlation between FOT, R and CT parameters to detect onset of clot formation. The thrombin parameters were highly dependent on sample type and triggering agent and did not significantly vary between the two groups. Further studies are needed to clarify the clinical significance of these findings. Disclosures: Ezban: NovoNordisk A/S: Employment. Hedner:NovoNordisk A/S: Employment.


Author(s):  
Yaiza Herrero ◽  
Rahel Jud Schefer ◽  
Benjamin M. Muri ◽  
Nadja E. Sigrist

Abstract Objective The aim of this study was to determine the prevalence of acute traumatic coagulopathy (ATC) and identify associated clinical and laboratory parameters including rotational thromboelastometry. Study Design Dogs presenting within 6 hours after trauma were allocated to the ATC or non-ATC group based on thromboelastometry analysis (ex-tem S, in-tem S, fib-tem S). ATC was defined as ≥2 hypocoagulable parameters in 1 profile and ≥ 1 hypocoagulable parameter in an additional profile. Parameters used were ex-tem and in-tem clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF), maximum lysis and fib-tem MCF. Clinical and laboratory parameters at presentation, animal trauma triage (ATT) score, transfusion requirement and outcome were compared. Logistic regression was used to identify independent factors associated with ATC. Results Eleven of 33 dogs presented with ATC and showed ex-tem CT and CFT prolongation and reduced MCF amplitude in all profiles (all p < 0.001). pH (p = 0.043) and potassium concentration (p = 0.022) were significantly lower and bleeding (p = 0.027) and plasma transfusions (p = 0.001) more common in dogs with ATC. Time after trauma (p = 0.040) and Animal Trauma Triage score (p = 0.038, including haematocrit as confounding factor) were associated with the presence of ATC. Conclusion Acute traumatic coagulopathy is more common in traumatized dogs than previously reported. Acute traumatic coagulopathy was associated with acidosis, Animal trauma triage score, time after trauma and higher transfusion needs. Coagulation abnormalities include ex-tem CT and CFT prolongations and decreased clot strength.


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