Articles: prothrombin-time.
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J Am Assoc Lab Anim · Nov 2011
Comparative StudyDetermination of plasma fibrinogen concentrations in beagle dogs, cynomolgus monkeys, New Zealand white rabbits, and Sprague-Dawley rats by using Clauss and prothrombin-time-derived assays.
The most widely used technique for determination of fibrinogen concentration is the Clauss fibrinogen (FIB(Clauss)) assay, which measures the clotting time of plasma after addition of excess thrombin. More recently, the PT-derived fibrinogen (FIB(PT)) assay has been developed, based on the relationship between fibrinogen concentration and the kinetics of clot formation during the prothrombin time. The objective of this study was to compare the fibrinogen concentration determined by the FIB(Clauss) and FIB(PT) assays in citrated plasma samples from healthy dogs (n = 40), monkeys (n = 40), rabbits (n = 26), and rats (n = 58) by using an automated coagulation analyzer. ⋯ In conclusion, the FIB(PT) assay is a rapid and economical method for estimating fibrinogen concentration in plasma samples from dogs, monkeys, rabbits, and rats. However, it should not be used without restriction. Further studies are required to investigate the performance of this assay in animals with various pathologic states, including coagulopathy, dysfibrinogenemia, and hypo- or hyperfibrinogenemia.
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Blood Coagul. Fibrinolysis · Mar 2011
An assessment of the utility of unselected coagulation screening in general hospital practice.
Coagulation screening using prothrombin time (PT) and activated partial thromboplastin time (APTT) is widely used. We performed an audit of coagulation screening in an Irish teaching hospital. We analysed PT and/or APTT results received during normal working hours during a 1-week period in our hospital. ⋯ APTT was longer than 50 s in four of 353 (1.1%). No patients with abnormal PT or APTT had any bleeding sequelae during the study period. Unregulated coagulation screening has a low yield of abnormal results; the majority of these abnormal results show mild prolongation of PT or APTT with no evidence that they are associated with an increased bleeding risk.
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Multicenter Study
A national study of plasma use in critical care: clinical indications, dose and effect on prothrombin time.
Fresh frozen plasma (FFP) is widely used, but few studies have described patterns of plasma use in critical care. We carried out a multicentre study of coagulopathy in intensive care units (ICUs) and here describe overall FFP utilisation in adult critical care, the indications for transfusions, factors indicating the doses used and the effects of FFP use on coagulation. ⋯ There is wide variation in FFP use by ICU clinicians, and a high proportion of current FFP transfusions are of unproven clinical benefit. Better evidence from clinical trials could significantly alter patterns of use and modify current treatment costs.
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Journal of neurosurgery · Jan 2011
Comparative StudyCoagulation factor levels in neurosurgical patients with mild prolongation of prothrombin time: effect on plasma transfusion therapy.
Neurosurgical patients often have mildly prolonged prothrombin time (PT) or international normalized ratio (INR). In the absence of liver disease this mild prolongation appears to be due to the use of very sensitive PT reagents. Therefore, the authors performed relevant coagulation factor assays to assess coagulopathy in such patients. They also compared plasma transfusion practices in their hospital before and after the study. ⋯ Neurosurgical patients with a mild prolongation of INR (up to 1.7) have hemostatically normal levels of important coagulation factors, and the authors recommend that plasma not be transfused to simply correct this abnormal laboratory value.
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Frozen plasma (FP) is commonly used for the treatment of bleeding or the prevention of bleeding in critically ill patients, but clinical evidence to help aid the critical care clinician make decisions on whether to transfuse or not is at present limited. Despite the limited evidence, it appears FP is administered not infrequently in the absence of bleeding or with no required procedure when the international normalized ratio (INR) is essentially normal (<1.5) or only mildly deranged (<2.5). The study by Stanworth and colleagues in a recent issue of Critical Care raises awareness of FP transfusion use in the critically ill, should prompt a consideration of curbing its use when it is not clearly appropriate, and illustrates the need for future high quality evidence to guide FP use in the critically ill when the risk:benefit ratio is less clear.