Articles: partial-thromboplastin-time.
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The study examined a "percent correction" formula for evaluating mixing study results comparing a 1:1 mix with a new 4:1 mix of patient plasma with citrated normal plasma for a prolonged activated partial thromboplastin time (aPTT) and/or prothrombin time (PT). The study also examined 3 suggested definitions of correction for evaluating mixing study results for comparison. Applicability of percent correction for evaluating the aPTT 4:1 mix testing with and without incubation also was studied. ⋯ The percent correction of the aPTT 4:1 mix testing after incubation had better sensitivity and specificity that that of testing immediately. Nevertheless, these procedures were complementary to each other. The percent correction using the aPTT or PT 4:1 mix seemed to offer a simple, objective, and effective criterion for evaluating mixing study results.
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Comparative Study
Correlation between activated clotting time and activated partial thromboplastin times.
To evaluate the correlation between clotting time tests and heparin concentration, the correlation between activated clotting time (ACT) and activated partial thromboplastin time (aPTT) results, and to compare the clinical decisions based on ACT results with those based on aPTT results. ⋯ The laboratory-based aPTT has a stronger correlation to heparin concentration than the bedside-based aPTT and ACT. The correlation between ACT and aPTT was similar among 3 different aPTT instruments. Decisions to adjust heparin therapy based on ACT results differed from decisions based on aPTT results more than one-third of the time.
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Int. J. Pediatr. Otorhinolaryngol. · Dec 2001
Clinical TrialThe need for routine pre-operative coagulation screening tests (prothrombin time PT/partial thromboplastin time PTT) for healthy children undergoing elective tonsillectomy and/or adenoidectomy.
In some medical centers, the routine pre-operative evaluation of healthy children undergoing elective tonsillectomy and/or adenoidectomy (T and A) includes coagulation screening tests (PT, prothrombin Time; PTT, partial thromboplastin time; and INR, international normalized ratio). In this retrospective study, we determined whether there is a positive correlation between prolonged PT/PTT/INR tests in healthy children, with no prior medical history of coagulation problems, and bleeding during surgery and/or bleeding in the month following surgery. We reviewed the records of 416 elective T and A surgeries performed at the Soroka University Medical Center in Beer-Sheva, Israel, over the course of 1999. ⋯ Two (3.3%) of the 61 with prolonged PTT values experienced light bleeding during the 1st month subsequent to surgery. We therefore concluded that pre-operative coagulation screening tests provide low sensitivity and low bleeding predictive value. As such, routine coagulation tests before T &A are not indicated unless a medical history of bleeding tendency is suspected.
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Comparative Study Clinical Trial
Point of care and central laboratory determinations of the aPTT are not interchangeable in surgical intensive care patients.
The objective of the study was to compare a bedside whole blood activated partial thromboplastin time (aPTT) performed by a point of care (POC) apparatus (CoaguCheck(R) Pro) in surgical intensive care (SIC) patients with a conventional aPTT obtained from the central laboratory. ⋯ POC aPTT and central laboratory aPTT showed a poor agreement in SIC patients admitted after surgery, although in healthy volunteers or in control patients, this agreement was better. The best test to monitor heparin treatment in this setting was anti-factor Xa activity.
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Although low molecular weight heparin (LMWH) is increasingly being used in the treatment of acute coronary syndrome (ACS), unfractionated intravenous (IV) heparin infusion is still widely used in Australian hospitals for the treatment of ACS. This paper evaluates the effectiveness of a non-weight based heparin regimen in achieving a therapeutic activated partial thromboplastin time (aPTT) within 24 hours of IV heparin commencement. A sequential retrospective chart review of 99 medical records of ACS patients in a district hospital in south western Sydney, Australia, was performed. ⋯ Comparison of therapeutic aPTT and non-therapeutic aPTT groups revealed that body weight was the only factor that was significantly different in the two groups. Patients who reached the therapeutic aPTT threshold within 24 hours weighed significantly less (mean body weight: 70.3 kg versus 80.3 kg) than those who did not reach the therapeutic threshold within 24 hours of heparin commencement (t = 3.80, d.f. = 86, p < 0.001). Given that a significant proportion of patients who require IV heparin therapy exceed the 70 kg body weight, the findings from this study suggest that a non-weight based heparin regimen is ineffective in the rapid achievement of therapeutic aPTT.