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At least 325 records · Page 18Linked to original sources
PubMed1990

Orbitometer flow and thrombus formation.

Orbitometry (Hartert) is a rheological ex-vivo method to follow up physical assembly of a coagulum in layers during natural intensity of flow by orbital movement. Fibrin elasticity in the Orbitometers mode of Resonance Thrombography is differentiated from platelet activity as well as e.g. from the effects of disseminated coagulation-minimal in liver disease and maximal during disturbances of delivery. Transition into the mode of dynamic Tendography (Hartert) will e.g. register all fast going tests lasting minutes or seconds. It is comparable to an accelerated form of Thrombelastography (Hartert), the intercourse of which with coagulum yet is an exclusively static operation. Another category is measurement of blood and plasma viscosity. In concentrated blood it seizes plasticity of blood cells as well as their intensity of aggregation in orbital flow. The latest methodical development of Orbitometry is control of platelet activity in its function of adhesion. This is realized by measurement of specific physical effects released in platelet containing coagulum. They generate a structural degradation of fibrin elasticity modul as well as a tendency for coagulum adhesion. The practical use of Adhesiography is control of anticoagulants and platelet protecting substances in their quantitative influence on coagulum structure and on the mentioned platelet activities. A special disturbance of these platelet depending mechnisms obviously is getting evidence in case of v. Willebrand's syndrome.

Blood Coagulation Disorders↗
PubMed1998

Hematological abnormalities in neonatal patients treated with extracorporeal membrane oxygenation (ECMO).

The physical process of extracorporeal membrane oxygenation (ECMO) results in derangement of the hemostatic mechanism, which may lead to increased morbidity, secondary to the disease process. The purpose of this study was to evaluate the hematological status of neonates undergoing ECMO therapy, and to evaluate coagulation tests in predicting hemorrhagic risk. Following Institutional Review Board approval, 30 patients undergoing ECMO treatment were retrospectively entered into this study. Medical records were reviewed and indicators of hemostasis, transfusion, morbidity, and outcomes recorded. Assessment of coagulation was determined through serial analysis of platelet count, fibrinogen concentration, prothrombin time (PT), activated partial thromboplastin time (aPTT), antithrombin III, fibrin split products, D-dimers, plasma free hemoglobin, activated clotting time, ionized calcium, and thrombelastography (TEG). Median total transfusion requirements for all patients were 1.79 ml/kg/ECMO hr. Fifty-seven percent of the 30 patients were diagnosed as coagulopathic according to Extracorporeal Life Support Organization standards. Patients were separated into either a hemorrhagic group (HEM, > 2.0 ml/kg/ECMO hr, n = 13) or a nonhemorrhagic group (N-HEM, n = 17), with HEM patients requiring twice the transfusion volume of N-HEM (p < 0.0001). Hemorrhagic complications were reported in 53.8% of the HEM patients vs. 35.3% in the N-HEM group. HEM patients were transfused with significantly greater quantities of platelets on days 1, 3, 5, and 8 and packed red blood cells on day 7 when compared to N-HEM (p < 0.05). TEG determination showed significant differences between groups on days 3 and 6 (p < 0.005), and 8 (p < 0.05). Derangements in hemostasis resulting from ECMO are profound, with methods of assessing coagulation complicated by both the variability in patient condition and lack of specificity of laboratory tests. Interpretation of TEG data has shown to be a valuable supplement for managing this challenging patient population.

Antifibrinolytic Agents↗
PubMedDate not supplied

Thrombelastographic patterns during cryotherapy for recurrent hepatocellular carcinoma.

A cirrhotic patient with recurrent hepatocellular carcinoma and thrombocytopenia undergoing cryotherapy showed: 1) transient hyperfibrinolysis shortly after platelet transfusion, and 2) evidence of activation of coagulation after freezing and thawing of tumor as measured on the thrombelastography. No anti-fibrinolytic treatment was required for the hyperfibrinolysis which subsided spontaneously in this patient. This case report highlights that: 1) in patients with chronic liver disease, platelet transfusion might potentially worsen rather than improve the hemostatic function by activation of fibrinolysis, and 2) activation of coagulation may underlie the perioperative coagulation changes seen in cryotherapy.

Carcinoma, Hepatocellular↗
PubMed1975

The influence of beta-adrenergic blockade upon baseline blood coagulation and fibrinolytic activity and upon the responses to venous occlusion.

Twenty volunteers were assessed for baseline coagulation (Thrombelastography, Factor VIII and platelet count) and fibrinolytic (Euglobulin Lysis Time and Fibrin(ogen) Degradation Products) activity two hours after ingestion of 60 mgm propranolol or an identical placebo administered on a double blind basis. The responses of these parameters to a fifteen minute period of venous occlusion was also assessed. Beta adrenergic blockade reduced baseline FDP titres but did not affect other parameters, nor the local response to venous occlusion. During occlusion no significant change in coagulation activity could be detected in the non-occluded arm, but a small but statistically significant shortening of ELT was observed. Since this effect was prevented by propranolol it is probably mediated through adrenergic mechanisms. Adrenergic stimuli appear to influence episodes of coagulation and fibrinolysis during everyday activity, but do not contribute to baseline levels of coagulation or fibrinolytic function.

Adult↗
PubMed2006

[Effects of preoperative acute hypervolemic hemodilution on hypercoagulability of patients with colon cancer].

BACKGROUND & OBJECTIVE: Cancer patients have an increased risk of thrombosis after operation because of a hypercoagulable status. Therefore, anticoagulant treatment is necessary for patients with hypercoagulability during perioperative period. This study was to investigate the effect of acute hypervolemic hemodilution (AHHD) with 6% hydroxyethyl starch (HES), or 4% succinylated gelatin (GEL), or lactated Ringer's (RL) solution before operation on the hypercoagulable status and the occurrence of deep venous thrombosis (DVT) of patients with colon cancer. METHODS: Sixty colon cancer patients with hypercoagulable status underwent operation were randomized into HES, GEL, and RL groups; each group contained 20 patients. The patients were infused with HES, GEL, or RL solution respectively at a dose of 15 ml/kg within 30 min before operation. Preoperative coagulation function was assessed by thrombelastography (TEG). DVT was diagnosed by the color Doppler ultrasonic system. RESULTS: Acute hypervolemic hemodilution with HES solution led to a significant decrease of coagulation index (CI) at 30 min and 2 h after starting operation and 1 h after operation as compared with the prehemodilution value (P<0.01). At 1 h after operation, CI was significantly lower in HES group than in GEL group (P<0.05). At 30 min and 2 h after starting operation and 1 h after operation, CI was significantly lower in HES group than in RL group (P<0.05). Hemodilution with GEL solution lessened CI at 30 min and 2 h after starting operation significantly as compared with the prehemodilution value (P<0.01). At 30 min and 2 h after starting operation, CI was significantly lower in GEL group than in RL group (P<0.05). After operation, DVT in occurred 2 (10%) patients in HES group, 3 (15%) in GEL group, and 10 (50%) in RL group (P<0.05). CONCLUSION: Acute hypervolemic hemodilution with HES solution and GEL solution can alleviate the hypercoagulability of colon cancer patients during perioperative period and decrease the occurrence of DVT.

Adult↗
PubMedDate not supplied

[Comparison of the mechanical properties of resorbable bone substitutes].

The mechanical properties of blood clots stabilized with collagen, gelatine and alginate sponges were compared with the oid of thrombelastography and volumetric tests. The collagen sponges were distinctly inferior to gelatine and alginate in stabilizing the clot against retraction. There was no evidence of any interaction between collagen and blood clot.

Alginates↗
PubMed1990

[Mechanical properties of collagen or gelatine-stabilized blood clots].

Mechanical properties of blood clots stabilized with collagen (Pentapharm) and a gelatine (Gelastypt-M) sponge were compared with the help of thrombelastography and volumetric tests. The collagen songe was distinctly inferior to gelatine in stabilizing the clot against retraction. It appears that gelatine is a better material for filling large osseous defects that are subjected to mechanical stress.

Animals↗
PubMed1990

Thrombelastograph monitoring: a clinical perspective.

Thrombelastography (TEG) has been used widely during hepatic transplantation procedures to detect intraoperative changes in blood coagulation and as a guide to determine appropriate treatment of these changes. The current literature identifies the use of TEG for intraoperative management of coagulation as a proven reliable and rapid monitoring system. The clinical applicability of TEG monitoring for the anesthesia provider will give better intraoperative management of hemostasis, optimizing patient care and minimizing blood component use.

Blood Coagulation Disorders↗
PubMed1986

In vitro comparison of fibrinolytic activity of plasminogen activators using a thrombelastographic method: in vivo evaluation of the B-chain-streptokinase complex in the dog model using pre-titered doses.

Thrombelastography was used to quantitatively compare the clot-lysing efficiency of 6 different plasminogen activators, using human whole blood, pooled normal plasma, and platelet rich plasma. The activators compared were the B-chain-streptokinase complex, the plasmin-streptokinase complex, the mini-plasminogen-streptokinase complex, tissue plasminogen activator, streptokinase, and urokinase. The most efficient activator found was the B-chain-streptokinase complex. This complex was 4.0 times more effective than streptokinase, 3.0 times more effective than the plasmin-streptokinase complex, 1.3 times more effective than the mini-plasminogen-streptokinase complex, 2.3 times more effective than tissue plasminogen activator, and 16.0 times more effective than urokinase. Although there were differences in both the coagulation and fibrinolysis thrombelastographic patterns between plasma and whole blood, the comparative efficiencies of each activator were the same with either plasma or blood. The B-chain-streptokinase complex was evaluated as a thrombolytic agent in clot-lysis experiments in the jugular vein in the dog model, using a thrombelastographic method to determine the minimum dose of activator necessary for clot-lysis. With 6 dogs infused locally with 0.25 mg (8000 I.U.) of the plasmin-streptokinase complex, the cumulative clot-lysis was 18.0 +/- 3.0% with the first dose, 33.0 +/- 2.1% with the second dose, and 55.2 +/- 8.6% with the third dose. With 6 dogs infused locally with 0.03 mg (2000 I.U.) of the B-chain-streptokinase complex, the cumulative clot-lysis was 30.6 +/- 6.4% with the first dose, 54.4 +/- 9.6% with the second dose, and 80.2 +/- 9.0% with the third dose.

Animals↗
PubMed1978

[Determination of blood coagulation in acute obstetrical and gynecologic hemorrhages by means of the Hellige direct writing thrombelastograph].

Thrombelastography, as a method of rapid registration, is an important addition to the present screening tests of coagulation status. With this method we are able to quickly obtain exact values for clotting and fibrinolysis with more precision than those which can be obtained from the clot observation test. The TEG monitor must however be available in the immediate vicinity of the labour ward and must be ready for use around the clock. Specific therapy for the elimination of failures in hemostasis may then be started without delay, due to prompt determination of coagulation status and early detection of fibrinolysis.

Blood Coagulation↗
PubMed1979

[Thromboelastographic and immunologic fibrinolysis determinations in inflammatory-changed and artificial blood stained cerebrospinal fluids using fibrinogen substrate].

In in-vitro long-term tests, the free fibrinolytic activity was determined from inflammatory-changed and blood stained cerebrospinal fluids in which partly fibrinogen concentrations insufficient for the enzyme-catalysed fibrinolytic reaction were present, using after addition of substrate (fibrinogen, plasma) thrombelastography and fibrin degradation products (FDP) recording. The results confirm a free fibrinolytic activity in many inflammatory-changed and blood stained cerebrospinal fluids. The difference in the results obtained with reaction preparations with substrate and those with too low fibrinogen concentrations are discussed.

Central Nervous System Diseases↗
PubMed1982

[Coagulation parameters in patients with hypertension].

Thrombelastography in the whole blood and determination of antithrombin III by means of chromogenic substrates were performed in a group of 10 patients with hypertension. The results of the thrombelastograms showed a slight shift toward hypercoagulability, as revealed by a significant increase in the thrombodynamic potential index. There was no significant change in antithrombin activity as compared with control group.

Adult↗
PubMed1981

[Clinical problems of microrheology in disseminated intravascular coagulation (author's transl)].

Among the earliest products of a potentially succeeding disseminated intravascular coagulation (DIC) are the soluble fibrin monomer complexes representing a state of hypercoagulability. They are passing microcirculation as long as there are no precipitation activities, which may involve only one single organ. A typical example is the endotoxin shock followed by fibrination of the kidneys. The clogging of microcirculation by fibrination specifically released in this organ or another may be prevented in case of a well-timed diagnosis, but scarcely can be removed therapeutically (possibly therapeutical fibrinolysis). The effects of localising fibrination yet independent of clotting mechanism may be tackled by treating the causal disease. Hypercoagulability always preceding DIC can be controlled mainly by heparin. Its well-timed application depends on diagnostics which are able to define the momentary situation in the mostly progredient process, comprising a mortality of about 50%. Finally, as a possible method to assess the clinical situation the resonance thrombography, a successor of thrombelastography, is put forward.

Blood Coagulation Disorders↗
PubMed1980

[Investigations of combined injuries, 28th communication: Troubles of hemostatic equilibrium arising from radiation and combined injuries (author's transl)].

In female mice the influence of total-body irradiation combined with excision of skin on the blood-clotting system was examined. Whereas the general tests of plasmatic coagulation showed no significant change, a biphasic course of coagulation disturbances in thrombelastography and euglobulin-clot-lysis following combined radiation injury was found. During the first time a pronounced increase of coagulability appeared, followed by the development of a hypocoagulability due to thrombocytopenia and functional disturbances of blood platelets. In this hemorrhagic period the euglobulin-clotlysis time was accelerated, but only after combined injury. Possible reasons are discussed.

Animals↗
PubMed1976

Chemorheological studies of the effect of heparin on the course of coagulation.

The influence of sodium heparin on viscoelastic change during coagulation was determined in vitro for whole blood samples from ten normal subjects at heparin concentrations ranging from 0 to 1.45 units/(ml whole blood). A four-parameter chemorheological model was used to describe the time course of coagulation as measured by the Weissenberg Rheogoniometer. One parameter compares closely with the whole blood activated partial thromboplastin time, while the other three may be related to the chemical kinetics of clotting. The chemorheological model and experimental techniques were then tested in a dog preparation. It was found that rheological measurements are more self-consistent than either thrombelastography or the activated partial thromboplastin time for the assay of in vivo heparin in two dogs.

Animals↗
PubMed1990

Rheological studies on patients with posterior subretinal neovascularization and exudative age-related macular degeneration.

To investigate the potential influence of a decreased perfusion rate of the choriocapillaris on the development of age-related macular degeneration (ARMD) with subretinal neovascularization (SRNV) apparently caused by disturbed flow properties of blood, we compared the hemorheological parameters of blood from 35 patients suffering from ARMD with SRNV with those from the 35 healthy patients of the same age. In both groups hematocrit, plasma viscosity, erythrocyte filtrability, aggregation, aggregating proteins, leukocyte and thrombocyte count, differentiation of leukocytes, thrombelastography, PTT, Quick test, and rheological profiles were comparable. The differences were not significant (P greater than 0.05). These results refute the hypothesis that changed flow properties of blood are the primary cause of the pathogenesis of ARMD with SRNV.

Aged↗
PubMed1990

The new phosphodiesterase inhibitor enoximone in patients following cardiac surgery--pharmacokinetics and influence on parameters of coagulation.

Enoximone is a selective inhibitor of the phosphodiesterase-III enzyme (PDE-III) and possesses positive inotropic and vasodilatory properties. The PDE-inhibitor amrinone has been associated with adverse effects on coagulation by decreasing platelets. To investigate the influence of enoximone on hemostasis, 18 patients undergoing elective aorto-coronary bypass grafting and receiving enoximone were compared to a control group (n = 18). In addition, the plasma levels of enoximone and its major metabolite (enoximone-sulfoxide) were studied following a single injection (0.5 mg/kg) and during a continuous infusion (5 and 10 micrograms/kg.min) before, during and after extracorporeal circulation (ECC). No difference between study and control groups was found for the parameters of coagulation during the investigation period; in particular there were no differences in platelet count and platelet function (thrombelastography). Following the single bolus, peak plasma levels decreased during ECC to ineffective levels. Continuous infusion, however, maintained effective plasma levels of enoximone; sulfoxide levels were twice as high as enoximone concentrations up until the end of the investigation period. It is concluded that enoximone can be judged to be safe in respect to its effects on coagulation even following ECC and at relatively high doses. The use of continuous infusion results in plasma levels which remain at an effective concentration through to the time that the patient is transferred to the intensive care unit.

Aged↗
PubMed1993

Haemocompatibility optimisation of implants by hybrid structuring.

State of the art in biomaterial research and implant design is a compromise between functionality and biocompatibility. Consequently, results often have disadvantages with respect to both aspects. With regard to biocompatibility, the activation of the clotting system by alloplastic materials is of great significance, because it necessitates anticoagulant therapy. Further improvements in implant technology require an understanding of the interactions between blood and implants. Therefore a microscopic model of thrombogenesis at alloplastic surfaces is briefly presented, relating thrombogenicity of a material to the electronic structure of its surface. The electronic requirements for high haemocompatibility, which result from this model (especially a low band-gap density of states and a high surface conductivity) are fulfilled by an amorphous alloy of silicon and carbon (a-SiC:H). The advantage of amorphous materials is that they do not obey stoichiometric rules. Thus they allow a continuous adjustment of the electronic parameters without fundamental changes in their mechanical and chemical properties. The theoretical results were checked in vitro by total internal reflection intrinsic fluorescence (TIRIF) spectroscopy as well as thrombelastography experiments (TEG). In comparison with conventional materials such as titanium or LTI carbon, the TEG-clotting time of a-SiC:H-coatings was prolonged by in excess of 200 per cent. As a consequence, a-SiC:H is well suited as a haemocompatible coating material for hybrid structuring of cardiovascular implants.

Biocompatible Materials↗