A simplified method for monitoring heparin therapy at the bedside: The activated whole blood clotting time

Forman, Walter B.; Bayer, Gerald K.

doi:10.1002/ajh.2830110308

Cited by 6 publications

(2 citation statements)

References 11 publications

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“…Heparin was assayed by the activated whole blood clotting time test (ACT) 14 and on the Multi stat III using Diacrome-heparin (Wellcome Diag nostics, Research Triangle Park, NC) as the chro mogenic synthetic substrate. Heparin reference curves were obtained by adding the heparin prepar ations used clinically for the patients to normal pooled human plasma.…”

Section: Methodsmentioning

confidence: 99%

Hemostasis Changes During Cardiopulmonary Bypass Surgery

Mammen¹,

Koets²,

Washington³

et al. 1985

Semin Thromb Hemost

307

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A number of hemostasis parameters were studied in a total of 63 patients undergoing cardiopulmonary bypass (CPB) for open heart surgery. In 33 patients fibrinogen, Factors II, V, VIII:C, X, XI, antithrombin, plasminogen, alpha 2-antiplasmin, and platelet counts were assayed before surgery, during maximal hypothermia, at the end of the bypass procedure, before and after protamine sulfate infusion, in the intensive care unit, and 48 hours postoperatively. All factors assayed decreased markedly when the patients were placed on the bypass machine, the drop fairly well paralleling the decrease in hematocrit. During bypass the factors remained low, although a slight tendency toward an increase was noted. Only platelet counts remained low with a decreasing trend until the end of bypass. In the intensive care unit a second decrease in fibrinogen, Factors II and V and antithrombin was noted. This drop was unrelated to four patients who experienced a greater blood loss during this time than the others. Forty-eight hours postoperatively, a marked increase could be found in all clotting factors and near normal levels were measured. Platelet counts remained low, however. The decrease in factors rarely dropped into a range where one would expect a compromised hemostasis (less than 30%). Although antithrombin levels decreased below 60%, no difficulties with heparinization were encountered. Several factors were assayed manually and by automated analyzer (Multistat III), and excellent correlations were found between both procedures. Also a good correlation was found between the activated whole blood clotting times and quantitative heparin assays. In 30 additional patients platelet function was studied before surgery, after thoracotomy, after heparin administration, after initiation of bypass, at maximal hypothermia, before and after protamine sulfate infusion, and 24 hours postoperatively. Platelet counts once again decreased as patients were placed on the CPB machine and remained low throughout the procedure. Mean platelet volumes were unchanged until protamine was given. At that time, a significant drop in mean platelet volume was recorded. Twenty-four hours postoperatively the volumes were normal again. Platelet aggregation studies were performed on a whole blood aggregometer using two concentrations of ADP, collagen, and ristocetin as aggregation inducers. A significant decrease in aggregability was seen when the patients were connected to the CPB apparatus.(ABSTRACT TRUNCATED AT 400 WORDS)

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Section: Methodsmentioning

confidence: 99%

Hemostasis Changes During Cardiopulmonary Bypass Surgery

Mammen¹,

Koets²,

Washington³

et al. 1985

Semin Thromb Hemost

307

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“…Like the aPTT it covers an acceptable range of heparin levels. It carries the same drawbacks as the aPTT and is also strongly influenced by the conditions of blood sam pling [26],…”

Section: Activated Clotting Timementioning

confidence: 99%

Laboratory Assessment of Antithrombotic Therapy: What Tests and If So Why?

Kher¹,

Dieri

Hemker

et al. 1997

Pathophysiol Haemos Thromb

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A critical review is given of the tests available for the assessment of the action of anticoagulants, such as heparins, oral anticoagulants and direct thrombin inhibitors, in patients under antithrombotic therapy. The principle of action and the performance of the thromboplastm time (PT), the activated partial thromboplastin time (aPTT), the whole blood clotting time, the thrombin time, the ecarin clotting time and the endogenous thrombin potential (ETP) is discussed, as well as the evidence behind the accepted therapeutic ranges. The two most common tests, PT and aPTT, respond in an essentially different way to clinically effective anticoagulation with hepa-rin and with oral anticoagulants. This means that they covar-iate with, but do not themselves represent the essential parameter influenced by anticoagulation. The experimental basis for the widely accepted two times prolongation of the aPTT as an indicator for adequate anticoagulation is shown to be meagre in the case of unfractionated heparin and lacking for the other anticoagulants. Common sources for error in the interpretation of anti-factor Xa- and anti-thrombin activity of heparins are indicated. Extensive experience with new tests like the ecarin clotting time and the ETP is still lacking. On the basis of preliminary data and in view of the importance of the enzymatic action of thrombin in the pathogenesis of thrombosis, the ETP is considered a possible candidate for a common parameter to assess different types of anticoagulants.

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Pharmacokinetics of Heparin V: In Vivo and In Vitro Factors Affecting the Relationship Between Concentration and Anticoagulant Effect of Heparin in Rat Plasma

Whitfield

Levy

1983

Journal of Pharmaceutical Sciences

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A simplified method for monitoring heparin therapy at the bedside: The activated whole blood clotting time

Cited by 6 publications

References 11 publications

Hemostasis Changes During Cardiopulmonary Bypass Surgery

Hemostasis Changes During Cardiopulmonary Bypass Surgery

Laboratory Assessment of Antithrombotic Therapy: What Tests and If So Why?

Pharmacokinetics of Heparin V: In Vivo and In Vitro Factors Affecting the Relationship Between Concentration and Anticoagulant Effect of Heparin in Rat Plasma

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