scholarly journals The Sonoclot: A New Thrombokinetic Coagulation Instrument

1977 ◽  
Author(s):  
R.D. Hamstra ◽  
G.E. Ens ◽  
S. Simons
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Formation Rate ◽  
Severe Bleeding ◽  
Axial Vibration ◽  
Clotting Time ◽  
Activated Clotting Time ◽  
Coagulation Tests ◽  
Disposable Plastic ◽  
Normal Adults

A new coagulation instrument (Sonoclot) has been evaluated in the laboratory, at the bedside, and in surgery. It was compared to the prothrombin time, activated partial thromboplastin time, activated clotting time, Lee-White clotting time, fibrinogen and thrombelastograph. Most coagulation tests are reported as time to a clot end point while the Sonoclot records a continuous thrombokinetic pattern by measuring the energy required to maintain axial vibration of a hollow plastic probe in 0.4 ml of whole blood while it clots. Disposable plastic probes and non-siliconized glass cuvettes are rapidly changed after testing. Results are a line pattern which has been analysed for Clot Onset (C0) and Clot Formation Rate (CFR). Native whole blood from normal adults (54 studied) has a C0 of 2-4.5 minutes and CFR of 4-8 chart units/minute. The only similar clotting instrument is the thrombelastograph (TEG). Sonoclot and TEG patterns correlate, the Sonoclot sensing change before the TEG. Whole blood clotting measured with the Sonoclot is a new method which distinguishes hypercoagulation, various levels of heparin, and severe bleeding problems from normal. The device is durable, stable, easy to operate, and portable, providing a permanent record in a few minutes.

scholarly journals Bedside Coagulation Tests in Diagnosing Venom-Induced Consumption Coagulopathy in Snakebite

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 583 ◽  
Author(s):  
Supun Wedasingha ◽  
Geoffrey Isbister ◽  
Anjana Silva
Keyword(s):  
Low Income ◽  
Whole Blood ◽  
Blood Clotting ◽  
Specific Treatment ◽  
Small Sample ◽  
Consumption Coagulopathy ◽  
Clotting Time ◽  
Wide Range ◽  
Coagulation Tests ◽  
Blood Clotting Time

Venom-induced consumption coagulopathy is the most important systemic effect of snake envenoming. Coagulation tests are helpful to accurately and promptly diagnose venom-induced consumption coagulopathy and administer antivenom, which is the only specific treatment available. However, bedside clotting tests play a major role in diagnosing coagulopathy in low-income settings, where the majority of snakebites occur. We conducted a literature search in MEDLINE® from 1946 to 30 November 2019, looking for research articles describing clinical studies on bedside coagulation tests in snakebite patients. Out of 442 articles identified, 147 articles describing bedside clotting assays were included in the review. Three main bedside clotting tests were identified, namely the Lee–White clotting test, 20-min whole blood clotting time and venous clotting time. Although the original Lee–White clotting test has never been validated for snake envenoming, a recently validated version has been used in some South American countries. The 20-min whole blood clotting time test is the most commonly used test in a wide range of settings and for taxonomically diverse snake species. Venous clotting time is almost exclusively used in Thailand. Many validation studies have methodological limitations, including small sample size, lack of case-authentication, the inclusion of a heterogeneous mix of snakebites and inappropriate uses of gold standard tests. The observation times for bedside clotting tests were arbitrary, without proper scientific justification. Future research needs to focus on improving the existing 20-min whole blood clotting test, and also on looking for alternative bedside coagulation tests which are cheap, reliable and quicker.

Platelets and whole blood coagulation

Perfusion ◽  
2000 ◽  
Vol 15 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Robert F Baugh
Keyword(s):  
Blood Sample ◽  
Whole Blood ◽  
Blood Clotting ◽  
Extended Period ◽  
Time Frame ◽  
Considerable Variability ◽  
Clotting Time ◽  
Platelet Activity ◽  
Activated Clotting Time ◽  
Whole Blood Sample

In our early work in developing activated clotting time (ACT) assays, it became apparent that changes occurred in coagulation times as a whole blood sample aged (0-6 h). Subsequent studies showed that the coagulation parameters of plasma obtained from the samples remained stable during this time frame. These changes in whole blood clotting times during storage were eventually traced to the platelets. Several years of work demonstrated that this change was due to the removal of the blood from the vascular lining. This recalled a mechanism that was originally put forth in the 1970s with the discovery of prostacyclin. In this postulated mechanism, platelets are ‘time-bombs’. They are kept under control by prostacyclin (PGI2) secreted by the vascular lining. Without this prostacyclin, platelets ‘preactivate’. Since that time, additional substances secreted by the vascular endothelium have been identified, such as nitric oxide, that also influence platelet activity. The ‘preactivation’ of platelets in a blood sample can be followed using an ACT. In the same donor, the preactivation is uniform and reproducible over an extended period (months). There is, however, considerable variability between donors. Some donors’ platelets preactivate dramatically, while other donors show hardly any change. Prostacyclin, added to the blood sample when it is collected, prevents this preactivation. The clinical significance of these observations has yet to be clearly established, but these observations raise a number of questions with respect to methods for improving platelet function during bypass and in evaluating the risk of platelet-mediated cardiovascular disease.

THE EFFECT OF EARLY BLOOD TRANSFUSION ON THE OUTCOME OF GASTROINTESTINAL HAEMORRHAGE

1987 ◽  
Author(s):  
S D Blair ◽  
S B Javanvrin ◽  
C N McCollum ◽  
R M Greenhalgh
Keyword(s):  
Blood Transfusion ◽  
Blood Coagulation ◽  
Whole Blood ◽  
Randomised Trial ◽  
Gastrointestinal Haemorrhage ◽  
Clotting Time ◽  
Prospective Randomised Trial ◽  
Coagulation Tests ◽  
To Receive ◽  
Upper Gastrointestinal

It has been suggested that mortality due to upper gastrointestinal haemorrhage may be reduced by restricting blood transfusion [1], We have assessed whether this is due to an anticoagulant effect in a prospective randomised trial.One hundred patients with severe, acute gastrointestinal haemorrhage were randomised to receive either at least 2 units of blood during the first 24 hours of admission, or no blood unless their haemaglobin was lessthan 8g/dl or they were shocked. Minor bleeds and varices were excluded As hypercoagulation cannot be measured using conventional coagulation tests, fresh whole blood coagulation was measured by the Biobridge Impedance Clotting Time (ICT). Coagulation was assessed at 24 hour intervals and compared to age matched controls with the results expressed as mean ± sem.The ICT on admission for the transfusion group (n=50) was 3.2±0.2 mins compared to 10±0.2 mins in controls. This hyper-coagulable state was partially reversed to 6.4±0.3 mins at 24 hours (p<0.001). The 50 allocated to receive no blood had a similar ICT on admission of 4.4±0.4 mins but the hypercoagulable state was maintained with ICT at 24 hours of 4.320.4 mins. Only 2 patients not transfused rebled compared to 15 in the early transfusion group (p<0.001). Five patients died, and they were all in the early transfusion group.These findings show there is a hypercoagulable response to haemorrhage which is partially reversed by blood transfusion leading to rebleeding

The Haemocompatibility of Biomaterials In Vitro: Investigations on the Mechanism of the Whole-blood Clot Formation Test

1992 ◽  
Vol 20 (3) ◽  
pp. 390-395 ◽  
Author(s):  
Thomas Groth ◽  
Katrin Derdau ◽  
Frank Strietzel ◽  
Frank Foerster ◽  
Hartmut Wolf
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Blood Clot ◽  
Formation Rate ◽  
Clot Formation ◽  
Coagulation Cascade ◽  
Contact Activation ◽  
Human Fibrinogen ◽  
Static Conditions

Twenty years ago Imai & Nose introduced a whole-blood clotting test for the estimation of haemocompatibility of biomaterials in vitro In our paper a modification of this assay is described and the mechanism of clot formation further elucidated. It was found that neither the inhibition of platelet function nor the removal of platelets from blood significantly changed the clot formation rate on glass and polyvinyl chloride in comparison to the rate tor whole blood. Scanning electron microscopy demonstrated that platelets were not involved in clot formation near the blood/biomaterial interface. Thus, it was concluded that the system of contact activation of the coagulation cascade dominates during clot formation under static conditions. The latter conclusion was supported by the fact that preadsorption of human serum albumin or human fibrinogen onto the glass plates used, decreased the clot formation rate in the same manner.

Autoprothrombin II of human origin

1961 ◽  
Vol 201 (4) ◽  
pp. 660-662 ◽  
Author(s):  
Orhan N. Ulutin ◽  
J. Frederic Johnson ◽  
Walter H. Seegers
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Human Origin ◽  
Clotting Time ◽  
Generation Test ◽  
Blood Clotting Time

Autoprothrombin II activity develops when prothrombin preparations of human origin are activated with purified thrombin at pH 8.2. Early during the activation an inhibitor seems to form. Concentrates of the autoprothrombin II can replace serum in the thromboplastin generation test provided platelets are used in the test, but not if a soy bean phosphatide is used. Dogs were given Coumadin in doses that lowered their own autoprothrombin concentration practically to zero. Then while continuing with use of the drug some purified autoprothrombin II was infused intravenously. This was tolerated very well. The autoprothrombin II concentration stayed at normal for 7 hr. In 24 hr none remained. The infusion was also followed by a shortening of the whole blood clotting time.

Heparin Concentrations Correlated To The Activated Whole Blood Clotting Time (Act) During Extracorporeal Circulation

1981 ◽  
Author(s):  
S Stenbjerg ◽  
E Berg ◽  
O K Albrechtsen
Keyword(s):  
Extracorporeal Circulation ◽  
Whole Blood ◽  
Blood Clotting ◽  
Heart Surgery ◽  
Open Heart Surgery ◽  
Open Heart ◽  
Excellent Correlation ◽  
Clotting Time ◽  
Automated Method ◽  
Blood Clotting Time

Heparin levels and ACT were followed during open heart surgery in lo patients. Heparin was assayed by an amidolytic method using substrate S-2222. ACT was determined with an automated method using celite and glass beads as activators of coagulation. Neither the hemodilution nor the depletion of platelets observed during extracorporeal circulation seemed to influence the ACT. An excellent correlation between the ACT and the actual heparin level was found in each patient with coefficients of correlation ranging from 0.73 – 0.97. A slightly better correlation was noticed for values of ACT below 600 seconds. It was concluded that the ACT is a valuable and reliable tool in control of heparinisation during open heart surgery.

Role of Trisodium Citrate in the Unclottability by Thrombin of Fibrinogen Metz

1975 ◽  
Author(s):  
C. Soria ◽  
J. Soria ◽  
M. Samama ◽  
E. Poirot ◽  
G. Kling
Keyword(s):  
Calcium Chloride ◽  
Whole Blood ◽  
Blood Clotting ◽  
Negative Charge ◽  
Trisodium Citrate ◽  
Thrombin Time ◽  
Clotting Time ◽  
Fibrin Formation ◽  
Blood Clotting Time

In a case of homozygous dysfibrinogenemia, the whole blood clotting time was moderately prolonged, while the thrombin clotting time was infinite, whatever dose or nature of thrombin used. Besides, the bleeding syndrome in this case was very weak.We observed also that only after trisodium citrate addition to purified fibrinogen, the abnormal fibrinogen became unclottable by thrombin even after addition of calcium chloride, since without trisodium citrate thrombin time was only prolonged.By immunoelectrophoresis and by isofocusing in the presence or in the absence of trisodium citrate, we therefore undertook to show that trisodium citrate reacts more strongly with the abnormal fibrinogen than with normal one. Thus, trisodium citrate conferring a negative charge to the pathological molecule, the abnormal fibrinogen became resistant to clotting with thrombin. Protamine sulfate, by positiving the charges of fibrinogen, partially corrects the defect in fibrin formation.

Anticlotting activity of phosvitin on chicken blood in vitro

1962 ◽  
Vol 203 (6) ◽  
pp. 1170-1172 ◽  
Author(s):  
Koji Sato ◽  
Kazutaka Homma ◽  
Jiro Gotoh
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Egg Yolk ◽  
Clotting Time ◽  
Chicken Blood ◽  
Blood Clotting Time

Phosvitin, a phosphoprotein isolated from the vitellin of egg yolk, prolonged the whole blood clotting time in the chicken blood in vitro. The degree of phosvitin's inhibition of coagulation was inversely related to the level of egg-yolk-like material in plasma induced by estrogen.

Sign in / Sign up

Export Citation Format

Share Document