Articles: prothrombin-time.
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Review Comparative Study
Drawing coagulation studies from arterial lines: an integrative literature review.
How much blood must be discarded from a heparinized arterial line to obtain accurate coagulation studies, specifically activated partial thromboplastin time? The published literature provides insight into the question and guidelines for practice in adult critical care. This article reviews and integrates findings from 14 research studies published from 1971 to 1993 on discarding blood from arterial lines for coagulation studies. ⋯ Studies have demonstrated that adequate discard volume for activated partial thromboplastin time is 6 times the catheter dead space. These results should not be generalized to systemically heparinized patients, pediatric patients, or other types of heparinized lines such as pulmonary artery, central venous, or Hickman catheters.
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J. Cardiothorac. Vasc. Anesth. · Aug 1993
Intraoperative measurement of activated partial thromboplastin time and prothrombin time by a portable laser photometer in patients following cardiopulmonary bypass.
Intraoperative capabilities to rapidly assess coagulation status following cardiopulmonary bypass (CPB) may be of benefit in providing optimal hemostasis and transfusion management, because CPB causes abnormalities in coagulation that may increase morbidity and mortality. The Ciba Corning 512 coagulation monitor (Ciba Corning, Medfield, MA) is a compact and portable device that rapidly determines the prothrombin time (PT) and activated partial thromboplastin time (APTT) in whole blood samples. One hundred patients requiring CPB had APTT and PT determined in whole blood specimens by the 512 coagulation monitor and in plasma specimens by the hospital laboratory from the same arterial blood sample obtained after protamine administration. ⋯ The 512 coagulation monitor accuracy was not affected by a variation of hemoglobin concentration or platelet count between 6 and 12 gm/dL and 15 to 300 x 10(9)/L, respectively. In conclusion, the 512 coagulation monitor provided a rapid APTT and PT result, but the APTT was less accurate. Speeding access to hospital laboratory results would be even more efficacious and accurate.
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Randomized Controlled Trial Comparative Study Clinical Trial
Accuracy of drawing coagulation samples from heparinized arterial lines.
To determine the accuracy of activated partial thromboplastin time and prothrombin time studies when samples are drawn through heparinized arterial lines. ⋯ Results indicated that the minimal amount of discard volume for accurate activated partial thromboplastin time values in this population of percutaneous transluminal coronary angioplasty patients was the catheter deadspace volume plus 2 mL (total 3.6 mL).
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Comparative Study Clinical Trial
Comparison of PT and aPTT values drawn by venipuncture and arterial line using three discard volumes.
Blood samples obtained through heparinized arterial catheters are used routinely for a variety of laboratory tests. Accuracy of coagulation studies performed from samples obtained in this fashion continues to be questioned, particularly in regard to the minimum discard volume necessary to clear the catheter of heparinized solution. ⋯ We recommend that when drawing prothrombin time and activated partial thromboplastin time samples from an arterial line, a 5.3-mL discard volume be used.
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The development of a multifactorial coagulopathy after massive transfusion is a well-recognized clinical problem that is almost always accompanied by hypothermia. The purpose of this study was to investigate the isolated effect of alterations of temperature on the integrity of the coagulation cascade. Prothrombin times and partial thromboplastin times were each performed 15 times on samples of pooled normal plasma at the temperatures of 37 degrees C, 34 degrees C, 31 degrees C, and 28 degrees C, as well as 39 degrees C and 41 degrees C. ⋯ The series of enzymatic reactions of the coagulation cascade are strongly inhibited by hypothermia, as demonstrated by the dramatic prolongation of prothrombin time and partial thromboplastin time tests at hypothermic deviations from normal temperature in a situation where factor levels were all known to be normal. Clinicians who deal with critically ill massively transfused hypothermic patients all recognize the inevitable appearance of a coagulopathy that has a multifactorial origin. Unless specifically considered, the contribution of hypothermia to the hemorrhagic diathesis may be overlooked since coagulation testing is performed at 37 degrees C, rather than at the patient's actual in vivo temperature.