Articles: partial-thromboplastin-time.
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Semin. Thromb. Hemost. · Oct 2008
ReviewStandardization and clinical utility of thrombin-generation assays.
Thrombin generation is a key process that determines the extent of a hemostatic plug or a thrombotic process. The ensuing thrombin burst is crucial for the formation of a stable fibrin clot. During its active life, thrombin exerts a multitude of highly regulated actions on the blood and the vessel wall, including the clotting of fibrinogen. ⋯ Thrombin-generation assays not only provide an overall assessment of hemostasis but also target potential extrahemostatic effects of the generated thrombin, a potent agonist of a multitude of cellular activation pathways. Moreover, estimation of an individual's thrombin-generation potential may correlate more closely with a hypercoagulable or hypocoagulable phenotype when compared with traditional coagulation tests. In this review, we discuss to what extent thrombin generation can be expected to reflect the clotting function of blood, the development and use of different thrombin-generation assay systems suitable for detecting changes in the kinetics of thrombin generation, and the clinical utility of thrombin generation.
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Although administration of heparin is a useful method for preventing deep venous thromboembolism, one limitation is the increased risk of bleeding. In this retrospective investigation, we evaluated the effect of heparin on the activated partial thromboplastin time (APTT) in parturients who received caesarean section under combined spinal and epidural anesthesia. ⋯ Subcutaneously administered heparin, 5000 units twice daily, might have a role in preventing deep venous thromboembolism in parturients undergoing caesarean section. Strict vigilance, however, should be provided against increased bleeding associated with epidural hematoma in parturients with an indwelling epidural catheter.
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To compare prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen concentration in canine blood samples collected via an indwelling IV catheter and direct venipuncture. ⋯ Agreement between the 2 techniques for sample collection was clinically acceptable for PT, APTT, and fibrinogen concentration at time 0 and 24 hours. It is often difficult or undesirable to perform multiple direct venipunctures in critically ill patients. Use of samples collected via an IV catheter to monitor PT and APTT can eliminate additional venous trauma and patient discomfort and reduce the volume of blood collected from these compromised patients.
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Hemorrhage after tonsillectomy and adenoidectomy remains a serious complication. Therefore, routine preoperative coagulation screening, including activated partial thromboplastin time (aPTT), prothrombin time (PT) and platelet count (PLC), are regularly performed, also for medicolegal reasons. In the recently published statement of the German Society of Otorhinolaryngology, Head and Neck Surgery the need for routine preoperative coagulation screening is discussed, but so far no standardized procedure had been established. According to this statement - at least for children - routine preoperative coagulation screening is not mandatory as long as the thorough medical history provides no evidence for a coagulation disorder ( http://www.hno.org/kollegen/gerinnung_te_ae.html ). The present study was undertaken to determine the occurrence of postoperative hemorrhage on the one hand, and the incidence of abnormal preoperative routine coagulation parameters or pathological anamnesis findings on the other. ⋯ The frequently performed determination of routine coagulation parameters (aPTT, PT, PLC) is not able to reliably identify relevant coagulation disorders or to predict the risk for postoperative hemorrhagic complications after adenoidectomy or tonsillectomy.
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Comparative Study
Comparison of two blood sampling methods in anticoagulation therapy: venipuncture and peripheral venous catheter.
To compare prothrombin time and activated partial thromboplastin time values in concurrent blood samples obtained by direct venipuncture and from a peripheral venous catheter. ⋯ In clinical applications, nurses may prefer the use of peripheral venous catheter to venipuncture both for the comfort of the patients who get anticoagulation therapy and for the prevention of the risks as a result of venipuncture. Application of peripheral venous catheter eliminates the risks of superficial bleeding, irritation, pain and anxiety caused by venipuncture.