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PubMed1988

Analysis of thromboelastogram on coagulation and fibrinolysis.

Hartert's thromboelastography has been used in the diagnosis of abnormal blood clotting for more than 20 years. From a thromboelastogram three parameters are obtained, viz, the reaction time 'r', the rate of formation of fibrin clot 'k', the maximum elasticity of thrombus 'amax'. It is desirable, however, to know the equation that describes the thromboelastogram both in the period in which the complex modulus increases with time because of coagulation, and in the period in which the complex modulus decreases with time because of fibrinolysis. The parameters of the equation could then be used as a diagnostic criterion; yielding information on the mechanism of coagulation and fibrinolysis. Based on our experimental results on human blood in normal and abnormal subjects, we found that the complex modulus of thromboelastograms can be expressed by the sum of two terms, one describing the increase of the complex modulus during coagulation, G1 = G'1 Exp (-tau 1/t), the other describing the decrease of the complex modulus during fibrinolysis, G2 = G'2 Exp (-tau 2/(t-D) when t greater than D. G2 = 0 when t less than D. The compound complex modulus from coagulation to fibrinolysis is G = G1 - G2. Here t is the clotting time, and G'1, G'2, tau 1, tau 2, and D are five constants to be identified. These five constants can be used for diagnostic and prognostic purposes.

Adult↗
PubMedDate not supplied

[State of the hemostasis and fibrinolysis systems in cesarean section under combined ketamine anesthesia].

The reserve potentialities of the hemostasis and fibrinolysis systems were studied by thromboelastography in 34 women with normal pregnancy aged 18-34 years at different stages of cesarean section under combined ketamine anesthesia. Three types of responses were observed: compensated, subcompensated, and decompensated. In women with subcompensated response removal of the fetus from the uterus involved in 30.1% cases depletion of the reserve potential of anticoagulant mechanisms, which led to abnormal blood loss in 34.7% cases.

Adolescent↗
PubMed1999

In vitro studies on the biochemistry and pharmacology of low molecular weight heparins.

Low molecular weight heparins (LMWHs) are obtained from unfractionated heparin by diverse chemical and enzymatic processes and findings with one LMWH cannot be extrapolated to another. Functional assays performed in vitro, evaluating antiprotease activity mediated via antithrombin III, heparin cofactor II interactions, antithrombin III binding, and plasma protein binding, showed wide variations between LMWHs, indicating that compositional differences among the LMWHs have a major impact on function. Evaluation in vitro showed varying potency in United States Pharmacopeia (USP) and anti-Xa assays. LMWHs tested at anti-Xa-adjusted concentrations exhibited varying potencies with anti-IIa, Heptest, and activated partial thromboplastin time (APTT) assays. Evaluation of these assays showed differences between LMWHs and a link with molecular weight. Each LMWH also varied in the in vitro neutralization by platelet factor 4, thrombin, and heparinase. LMWHs also varied in platelet interactions as assessed by whole blood clotting, thromboelastography and P-selectin expression, and in tissue factor pathway inhibitor release in cell culture. It was concluded that compositional variations in LMWHs give each product a unique biochemical profile. This profile, plus varying endogenous interactions and pharmacokinetic profiles may give rise to the clinical differences observed with LMWHs in specific indications.

Animals↗
PubMedDate not supplied

[Reserve capacities of blood coagulation and total lytic activities in patients with benign prostatic hyperplasia].

Prior to and after the double local arm hypoxia test, whole blood thromboelastography under lowered contact activation was used to examine hemostasis and total blood lytic activity in 27 males aged 59-68 years who had moderate benign prostatic hyperplasia (BPH) as assessed by the International Scale. The control group included 25 apparently healthy males. Only 40.7% of patients were found have adequate reserve capacities of the study systems. BPH induced tension of reserve capacities of total blood lytic activity in 37% of cases and their depletion in 22.3%, even then moderate symptoms of the disease occurred.

Aged↗
PubMed1975

Oral contraceptives, ABO blood groups, and in vitro fibrin formation.

The relation between oral contraceptive (OC) use, ABO blood groups, and in vitro fibrin formation, as measured by thromboelastography, was investigated in 4315 women. The thromboelastogram (TEG) measures the speed of fibrin formation (R, K) and clot firmness (Ma). More rapid fibrin formation and increased clot firmness were associated with current OC use, but not to the extent seen in pathologic states. This relation was not related to dose, estrogen-progestin type, or duration of exposure. Past and "never" OC users had similar TEG values, suggesting reversibility, and noncontraceptive estrogens had a minimal effect on the TEG. ABO blood groups were found to have only a slight association with TEG values. Subjects with blood group O showed a somewhat prolonged speed of fibrin formation as compared to all other subjects. A decreased clot firmness was found in AB subjects, but this did not persist among OC users.

ABO Blood-Group System↗
PubMed2001

Assessment of the resonance thromboelastograph CS-3 for differentiation of coagulation disorders: a pilot in vitro investigation of simulated post-cardiopulmonary bypass coagulopathies.

Resonance thromboelastography (RTG), a further development of the thromboelastogram (TEG), has been designed for improved differentiation of the effect of the plasmatic coagulation factors (increasing F-leg) and platelets (decreasing P-leg) on clot formation. It is based on the effect of clot elasticity on the resonance of a swinging wire. We assessed the RTG for its ability to differentiate coagulation disorders that frequently occur after cardiac surgery. The RTG was performed with a CS-3 Analyzer. Samples from 10 healthy volunteers were investigated after the following preparations: (1) baseline values, (2) dilution to a hematocrit of 30% and 20% with either hydroxyl ethyl starch (HES) 10% or plasma; (3) addition of 0.25, 0.5, and 1.0 IU/mL porcine heparin with and without heparinase; and (4) addition of 1.0, 3.0, 4.0, and 5.0 microg/mL of the antiplatelet agent abciximab (ReoPro). Increasing concentrations of abciximab led to a slower decrease or in the case of higher concentrations, to a persistent elevation of the platelet leg of the RTG. Dilution of the hematocrit with plasma had no effect on the fibrin and platelet leg; whereas, dilution with HES 10% led to an inhibition of the fibrin and platelet leg. Dilution of the plasmatic coagulation factors resulted in an inhibition of both the fibrin and the platelet leg. The addition of 0.25 and 0.5 IU/mL of heparin led to an increased coagulation time and inhibition of the fibrin and platelet legs. These effects were eliminated by the addition of heparinase. The RTG enables the evaluation of platelet function under the condition of a nonimpaired plasma coagulation system. Depletion of plasma coagulation factors and the administration of small amounts of heparin do not enable the distinction between residual effects of an anticoagulant, coagulation factor deficiency, or impaired platelet function. However, the heparin effects can be eliminated by the addition of heparinase. Further improvement may be achieved using a modified RTG by adding plasma coagulation factors in one channel for an improved evaluation of platelet function, even under the condition of a loss of procoagulants.

Abciximab↗
PubMed2002

The effect of surface modification and aprotinin on cellular injury during simulated cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) elicits derangements to the formed elements of blood because of the physical stresses of extracorporeal flow. Methods of reducing the impact of CPB include circuit surface modification and pharmacological supplementation. The purpose of this study was to examine the effects of aprotinin in combination with surface modification during simulated CPB. Fresh whole bovine blood was used to prime standard CPB circuits divided into four groups (N = 3): control (CTR), aprotinin 300 KIU/mL (APR), Poly (2-methoxyethylacrylate) coating (PMEA), and APR with PMEA (APR-PMEA). Physical stresses included venous reservoir negative pressure (-85 mmHg), arterial line pressure of 150 mmHg at 5 LPM, and air-blood interface, applied over a 90-minute period. Samples were drawn at the following times: 0, 10, 45, and 90 minutes. Endpoints included platelet count (PLT), plasma-free hemoglobin (PFHb), and thromboelastography (TEG). PLT did not change (138.9 +/- 15.0 vs. 102.9 +/- 21.0, p = ns) throughout the 90-minute experimental periods in any group. PFHb increased significantly (mean of 19- fold) throughout the experiment, but was not affected by any treatment. The TEG index declined in the CTR (3.6 +/- 0.4 vs. -16.2 +/- 2.9, p < .0003), PMEA (5.9 +/- 0.8 vs. -2.7 +/- 3.8, p < .02), and APR-PMEA (4.6 +/- 1.0 vs. -2.8 +/- 0.3 p < .0003) groups, but not in the APR group (3.6 +/- 2.2 vs. -1.3 +/- 3.3 p = .10). In conclusion, neither APR nor PMEA had an effect on either red cell hemolysis or PLT, but APR treatment alone significantly attenuated the derangements in coagulation induced in this extracorporeal model.

Animals↗
PubMed1976

Noninvasive prevention of thrombosis of deep veins of the thigh using intermittent pneumatic compression.

Intermitten venous compression promotes cyclic emptying and refilling of the veins and sinuses of the legs. It prevents stasis and formation of thrombi while the patient is on the operating table and during recovery. Once the patient is ambulatory, the system is discontinued. While the system is in use, thromboelastography, venous impedance plethysmography and venography, when indicated, are used to monitor the system. The intermittent pneumatic compression system is safe, simple and practical to use for almost all patients. There was no evidence of deep vein thrombosis or pulmonary embolism in 123 patients, as determined by an absence of clinical signs, a negative impedance plethysmogram and a negative venogram.

Adult↗
PubMed1992

[Effect of yiqi huoxue therapy on blood coagulation process in vivo].

YiQi HuoXue (YQHX) therapy is one of the most widely used treatments to deal with the coronary heart disease (CHD). This paper stressed on study the effects of YQHX therapy on blood coagulation process in vivo. The effects of several TCM preparations on CHD patients were observed by thromboelastography (TEG), prothrombin time, etc. After giving various preparations 20ml intravenously, the results of TEG showed that the values of r, k, c, 1 were decreased and ma increased by QiXue injection, the differences of k and ma were significant; while no significant change by Shen Qi injection and the k value was significantly reduced by DanShen injection. The results of prothrombin time with QiXue injection showed distinct dose-dependent effects, it shortened with 20ml and significantly lengthened with 40ml. This results suggested that there was complicated effects of different YQHX preparations as well as of different dosages.

Aged↗
PubMedDate not supplied

[Effect of intermittent normobaric hypoxic activity on the development of acute radiation disease].

The experiments on 260 male mice of colony SHK, 352 mongrel rats and 20 Wistar rats were carried out to study the ability of using the normobaric hypoxic stimulation method for acute radiation sickness. Hypoxic stimulation using gas mixture with 10% of oxygen and 90% of nitrogen was conducted for two weeks after irradiation for 30 min. every day. It is shown that under influence of ionizing radiation (7 and 5.5 Gy) the postradiation hypoxic action increased the 30-day survival rate of mice, reduced disturbances of the qualitative composition of leukocytes in peripheric blood, promoted more rapid restoration of thromboelastography indices and caused no reliable changes in the postradial content of albumin and creatinine in blood.

Acute Disease↗
PubMed1992

Hemostatic activity of the bovine parotid gland glycoconjugates.

The bovine parotid gland was studied by means of biochemical analyses and the glycoconjugates extracted were used to investigate the activity on the human hemostatic system. Thromboelastography was unable to reveal anticoagulant properties. Conversely, the Thrombin Time (TT) was prolonged in a statistically significant way and with dose-coupling response. Reptilase Time (RT) was affected by the highest concentration of extract suggesting that the bovine parotid glycoconjugates alter the fibrinogen polymerization.

Animals↗
PubMed1992

[Blood coagulation, fibrinolysis and various values of Lansbury's activity index in rheumatoid arthritis patients].

To clarify pathophysiological significance of blood coagulation and fibrinolysis in rheumatoid arthritis (RA) patients with various values of Lansbury's activity index, we analysed by means of the urokinase activated platelet rich plasma thromboelastography. In RA patients, coagulation time (k) and reaction time (r)+k were shorter, maximal amplitude (ma) was larger and lysis time (LT) was longer comparing with those in healthy control. Especially LT and ma showed marked differences between RA patients and control subjects. The mild RA patients whose Lansbury's activity indexes were 0-19% had significant differences from healthy control subjects, in order of LT less than ma less than r+less than k, the probability values were smaller. Significant coefficients of positive correlations with Lansbury's activity index were higher in order of LT greater than LT/k greater than ma x LT. These findings suggested that RA patients had fibrin formation, which had close relations with maximal amplitude (ma) and lysis time (LT) which had positive correlation with Lansbury's activity index.

Activities of Daily Living↗
PubMedDate not supplied

von Willebrand disease: a laboratory approach.

von Willebrand disease (VWD) is a common inherited bleeding disorder. Accurate diagnosis and classification of VWD is crucial for clinical management. A detailed clinical history, including that of bleeding, is required. A family and drug history are also important. Genetic factors such as blood group, and environmental factors such as stress, trauma, pregnancy and inflammation should also be considered. The age, ethnic group and hormonal status could also affect the von Willebrand factor (VWF) levels. No single test is robust enough to detect all variants of VWD. In view of the heterogeneity of the disease and limitations in assays, a battery of tests should be performed before a final diagnosis can be reached. These include the screening coagulation tests, factor VIII:C assay, VWF antigen assay, assessment of functional VWF which includes VWF ristocetin cofactor assays, VWF collagen binding assay, ristocetin-induced platelet aggregation and VWF multimer analysis. The newer ELISA techniques based on VWF binding with factor VIII glycoprotein (Gp) 1b and cerebrosides have also helped in determining certain unusual forms of VWD. The advent of new systems such as platelet function analysers (PFA), thromboelastography (TEG) and clot signature analysers (CSA), which are designed to assess either the primary platelet function or as a global haemostasis screen, have facilitated and simplified the diagnosis. However, few centres all over the world can perform all these expensive tests to provide a final diagnosis of VWD. We reviewed the laboratory investigations required for a diagnosis of VWD. Apart from congenital VWD, the possibility of acquired VWD should be considered in those with a negative past history of bleeding or in the presence of an underlying disease.

Algorithms↗
PubMed1992

[Hemodilutional and blood salvaging autotransfusions in a case of aplastic anemia].

A 28-year-old female, weighing 46 kg, 155 cm in height, with aplastic anemia underwent implantation of iliac bone to the head of the femur. A combined technique of hemodilution and intraoperative blood salvaging was applied to supplement the blood loss during the operation. Intraoperative monitoring included continuous arterial pressure, heart rate, electrocardiograph, SVO2, bleeding time, prothrombin time (PT), activated thromboplastin time (APTT), and thromboelastography. A total of 900 ml of blood was drawn and the same volume of 5% albumin solution was infused over half an hour before the beginning of the surgery. During the operation, 2100 ml of blood was lost, and 1260 ml of autologous blood, 400 ml of homogeneous red blood cells and 5 units of fresh platelet were infused. The values of PT, APTT, bleeding time were within normal ranges after the surgery. Only 3 units of fresh platelet was infused in 2 weeks after the surgery. It was suggested that hemodilution and salvaging autotransfusion is safely performed and beneficial to minimize homogeneous blood transfusion even in a case of aplastic anemia.

Adult↗
PubMed2005

Locoregional anesthesia and coagulation.

The introduction of low molecolar weith heparin (LMWE) and the strong antithromboembolic prophylaxis protocols used in the USA, underlined the risk of spinal hemorrhage in patients receveing a neuraxial blockade. On the other side, the efficacy of these techniques over general anesthesia doesn't allow the anesthesist to miss this pratice, where possible. So it's necessary to quantify the spinal hematoma risk in patients assuming these drugs. Unfortunately, routine investigations on coagulation factors and platelets count are not reliable if patients are receiving LMWE. Waiting for dynamic tests concerning the coagulative status such as thromboelastography (TEG), many hospitals follow many different guidelines. For these reasons peripherical nerve block techniques are a good alternative, since they are not influenced by the efficacy of the coagulation system.

Anesthesia, Conduction↗
PubMed1990

[A thromboelastographic method of determining the antiaggregation activity of the vascular wall].

Thromboelastography was used for the assessment of the vascular wall antiaggregation function; this function was determined as the activity of prostacyclin, synthesized and released by the vascular wall after local ischemia of the limb vessels, antiaggregatory towards the blood platelets. This method permits a rapid and easy objective assessment of the vascular wall antiaggregation function and gives information on the role of the blood ingredients, the prostacyclin activity contributing to their effect.

Blood Vessels↗
PubMed2006

Dose titration of recombinant factor VIIa using thromboelastograph monitoring in a child with hemophilia and high titer inhibitors to factor VIII: a case report and brief review.

The administration of recombinant factor VIIa (rFVIIa) is complicated by a wide inter-subject variation in response, a short half-life, evolving indications for use, and the absence of a test that has been shown to correlate with clinical effect. This report describes a method used to titrate rFVIIa to thromboelastography (TEG) parameters in a difficult to manage hemophilic patient with high titer inhibition to factor VIII. The current concepts of monitoring rFVIla administration in hemophiliacs and uncontrolled hemorrhage in cardiac surgery are briefly reviewed.

Child↗
PubMed1990

[Recurrent acute disorders of cerebral circulation].

The authors provide the results of examining 122 patients with recurrent disorders of cerebral circulation using ultrasonic dopplerography, computer-aided tomography, thromboelastography, measurements of blood viscosity, hematocrit, platelet and red blood cell aggregation. The pathogenesis of recurrent acute disorders of cerebral circulation are analyzed and approaches to their prevention are discussed.

Acute Disease↗