Reference intervals for coagulation tests in adults with different ABO blood types

IntroductionCoagulation tests are affected by many factors, such as age, race, and gestation. Although coagulation test results vary by ABO blood type, reference intervals of different ABO blood groups remain to be determined. This study aims to investigate the reference ranges of coagulation tests for different ABO blood groups in the Han population in South China.MethodsA retrospective study was conducted in the First Affiliated Hospital of Shantou University Medical College. In all, 9600 individuals aged between 20 and 79 years were included. Coagulation tests, including prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), thrombin time, and fibrinogen, were performed.ResultsThere was a significant difference in PT, INR, and aPTT among ABO blood groups. PT and INR varied slightly between ABO blood groups. There was a higher aPTT value in individuals in the O blood group than in those in non‐O blood groups, in both males and females across the included age range. No differences were found in thrombin time and fibrinogen between the ABO blood groups.ConclusionThe study provides reference data on coagulation tests from ABO blood groups in South China. The established reference intervals specific to ABO blood type, sex, and age may improve clinical decisions based on coagulation tests.     

Dabigatran deliberate overdose: two cases and suggestions for laboratory monitoring

Context: Dabigatran etexilate (dabigatran) is a direct thrombin inhibitor anticoagulant agent. There is limited information about the changes in coagulation profile and outcomes in overdose. A monoclonal antibody has been developed to neutralize the anticoagulant effect of dabigatran. Case reports describe enhanced clearance of dabigatran by haemodialysis as an intervention to prevent haemorrhagic complications – however, the threshold for initiating haemodialysis is not well defined in an asymptomatic patient with normal renal function. Case details: Two patients presented following deliberate dabigatran overdoses. A 55-year-old woman ingested 10?×?150?mg dabigatran. A 21-year-old woman with a history of systemic lupus erythematosus and pulmonary embolus ingested 100?×?110?mg dabigatran. Both were admitted to the intensive care unit and managed expectantly. Serial coagulation tests normalized over 60 h. The half-life of dabigatran was not prolonged following overdose, being calculated between 7 and 11 h in each case. There was positive correlation between international normalized ratio (INR), prothrombin time (PT) and activated partial thromboplastin time (aPTT) with plasma dabigatran levels. Conclusion: There is limited experience with dabigatran overdoses. Normal aPTT, PT and INR assays 12 h following deliberate ingestion indicate that the drug concentration is not high. Individual risk assessment of bleeding risk needs to be formulated for each patient and expectant management is reasonable in the presence of normal renal function and absent risk factors for bleeding.     

Low Levels of Prothrombin Time (INR) and Platelets Do Not Increase the Risk of Significant Bleeding when Placing Central Venous Catheters*

Abstract Background and Purpose:   Central venous catheters are frequently placed in intensive care medicine for multiple indications. The risk of severe bleeding after cannulation is considered to be increased in patients with abnormal coagulation, common in critically ill patients. Patients and Methods:   This open prospective trial, performed at two medical intensive care units and one hematology intermediate care ward, investigated whether insertion of a central venous catheter in patients with coagulopathy (prothrombin time ≤ 50% [International Normalized Ratio, INR, ≥ 1.5] and/or platelets ≤ 50 × 10⁹/l) bears an increased risk of bleeding. Results:   In 196 patients with and without severe disorders of hemostasis, no significant difference in decrease of hemoglobin after catheter placement was observed. In addition, no correlation between a significant drop in hemoglobin and increased levels of creatinine or urea was seen. Mechanical complications were similar in frequency compared to previous publications. Conclusion:   These findings demonstrate that coagulation disorders with altered prothrombin time (INR) or platelets do not increase the risk of significant bleeding when inserting a central venous catheter. Therefore, the prophylactic correction of coagulation by transfusion of blood products or coagulation factors is not necessary before central venous catheter insertion. *Trial registration: ClinicalTrials.gov NCT00448188.     

Establishing reference intervals of coagulation indices based on the ACL Top 700 system for children in Southwestern Fujian,China

BackgroundTill date, China has not issued industry standards for reference intervals (RIs) of pediatric blood coagulation indices. Here, we evaluated changes in the coagulation indices in the venous blood of healthy children aged 29 days to 12 years derived using the ACL Top 700 system and established appropriate RIs.MethodsWe analyzed venous blood from 1770 healthy children for five coagulation indices. RIs were established according to the Clinical and Laboratory Standards Institute C28-A3c guideline.ResultsThe coagulation indices were grouped by age. For prothrombin time (PT) and international normalization ratio (INR), the RIs of infants and toddlers were identical; preschool children had the same RI as school-age children. Pediatric RIs for PT and INR were slightly lower than those for adults. The RIs of activated partial thromboplastin time (APTT), thrombin time (TT), and fibrinogen (FIB) in childhood were divided into two groups by age (1 month to 1 year and 1–12 years). The RI of APTT in infants was the widest; the overall level of FIB in infants was the lowest; children's APTT and FIB RIs were lower than those of adults. The pattern of TT values and RI trends in childhood were similar to those of APTT.ConclusionsThere were minor changes in the RIs of coagulation indices for children. The RIs of PT, INR, APTT, TT, and FIB must be grouped by age. The RIs of coagulation indices for children were different from those for adults; therefore, establishing separate RIs for children is necessary.     

Emergency medicine misconceptions: Utility of routine coagulation panels in the emergency department setting

BackgroundCoagulation panels are ordered for a variety of conditions in the emergency department (ED).ObjectiveThis narrative review evaluates specific conditions for which a coagulation panel is commonly ordered but has limited utility in medical decision-making.DiscussionCoagulation panels consist of partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT), prothrombin time (PT), and international normalized ratio (INR). These tests evaluate the coagulation pathway which leads to formation of a fibrin clot. The coagulation panel can monitor warfarin and heparin therapy, evaluate for vitamin K deficiency, evaluate for malnutrition or severe systemic disease, and assess hemostatic function in the setting of bleeding. The utility of coagulation testing in chest pain evaluation, routine perioperative assessment, prior to initiation of anticoagulation, and as screening for admitted patients is low, with little to no change in patient management based on results of these panels. Coagulation testing should be considered in systemically ill patients, those with a prior history of bleeding or family history of bleeding, patients on anticoagulation, or patients with active hemorrhage and signs of bleeding. Thromboelastography and rotational thromboelastometry offer more reliable measures of coagulation function.ConclusionsLittle utility for coagulation assessment is present for the evaluation of chest pain, routine perioperative assessment, initiation of anticoagulation, and screening for admitted patients. However, coagulation panel assessment should be considered in patients with hemorrhage, patients on anticoagulation, and personal history or family history of bleeding.     

Coagulopathy parameters in patients with Crimean‐Congo hemorrhagic fever and its relation with mortality

Background: Crimean‐Congo hemorrhagic fever (CCHF) is an acute illness affecting multiple organ systems and characterized by ecchymosis, visceral bleeding, and hepatic dysfunction. In this study, we aimed to investigate the profile of coagulopathy markers (platelet count, activated partial tromboplastin time (aPTT), prothrombin time (PT), international normalized ratio (INR), fibrinogen, protein C, protein S, antithrombin III, activated protein C resistance (APCR), and D‐dimer) and their clinical significance in 83 CCHF‐infected patients. Subjects and methods: We studied 83 CCHF patients who were admitted to Ankara Numune Education and Research Hospital during the spring and summer of2007. We compared the coagulopathy markers of fatal CCHF patients (n=9) with nonfatal cases (n=74). Results: Platelet count, PT, aPTT, INR, and fibrinogen were prognostic factors associated with mortality for CCHF. Especially, platelet count<20×10⁹ cells/l and aPTT>60 sec were important. Protein C, protein S, APCR, and antithrombin III levels were not associated with mortality. Conclusion: Laboratory tests including classical parameters (platelet count, PT, aPTT, INR, and fibrinogen) of coagulopathy seem to be enough for the followup of CCHF. Protein S, protein C, APCR, and D‐dimer levels were not associated with mortality. J. Clin. Lab. Anal. 24:163–166, 2010. © 2010 Wiley‐Liss, Inc.     

Fresh Frozen Plasma Dosing for Warfarin Reversal: A Practical Formula

ObjectiveTo provide a practical formula for fresh frozen plasma (FFP) dosing for warfarin reversal.Patients and MethodsWe reviewed data on all adult patients who received a total of 7778 units of FFP for warfarin reversal at Sentara Norfolk General Hospital (Norfolk, VA) between April 1, 2009, and March 31, 2010. Patients with advanced liver disease, consumptive or dilutional coagulopathy, and administration of activated factor VII or prothrombin complex concentrate were excluded. First, we used regression analysis on the FFP1 subset (patients whose international normalized ratio [INR] was checked before and after 1 FFP administration) and derived a simple formula: DeltaINR (PreINR – PostINR) after 1 FFP = a × PreINR + b, where PreINR and PostINR are the INR values before and after FFP administration, respectively, and a and b are constants. In the validation step, the formula obtained for the FFP1 subset was repeatedly applied to the FFP2 (patients who received 2 units of FFP back-to-back without an intervening INR check), FFP3, and FFP4 subsets.ResultsA total of 956 patients were included. The formula DeltaINR after 1 FFP = 0.57 × PreINR – 0.72 explained 82.6% of the total variance in INR change in the FFP1 subset (n=308; P<.01). Including age, sex, weight, FFP-to-PostINR interval, or administration of vitamin K marginally improved the model. Repeated application of the FFP1 formula to the FFP2 to 4 subsets combined confirmed the accuracy of the FFP1 formula across the entire data set (n=643; R²=95% between predicted and actual DeltaINR; P<.01).ConclusionThis formula provides a practical and accurate method for FFP dosing for warfarin reversal.     

动态对比增强MRI衍生的药代动力学参数鉴别诊断原发性中枢神经系统淋巴瘤与胶质母细胞瘤

目的 探讨原发性中枢神经系统淋巴瘤（PCNSL）与胶质母细胞瘤（GBM）动态对比增强MRI衍生的药代动力学参数差异。方法 收集17例PCNSL与21例GBM,均接受常规及动态对比增强MR检查,测量双室Tofts模型下药代动力学参数容量转移常数（K^trans）、回流速率常数（K_ep）、血管外细胞外间隙容积分数（V_e）,及初始（60 s）对比剂浓度-时间曲线下面积（iAUC）。采用单因素方差分析比较PCNSL与GBM各自的强化瘤灶（ET）、瘤旁脑组织（PT）、正常侧脑组织（NP）间各参数差异;采用独立样本t检验比较二者间ET、PT、NP各参数的差异。结果 PCNSL与GBM间ET的K^trans、K_ep差异均有统计学意义（P均<0.05）,PT的K_ep差异有统计学意义（P<0.05）。PCNSL、GBM的ET与PT间K^trans、K_ep、V_e、iAUC差异均有统计学意义（P均<0.05）;PCNSL的PT与NP间K^trans差异有统计学意义（P<0.05）;GBM的PT与NP间K^trans及K_ep差异均有统计学意义（P均<0.05）。结论 动态对比增强MRI基于Tofts双室模型的药代动力学分析对PCNSL与GBM具有鉴别诊断价值。     

Correlations between rotational thromboelastometry (ROTEM) and standard coagulation tests following viper snakebites

BackgroundA high prevalence of venom-induced consumption coagulopathy has been reported in individuals with viper snakebites. Rotational thromboelastometry (ROTEM) is a rapid technique that could be advantageous in assessing and monitoring coagulation disorders.PurposeTo explore correlations between ROTEM and standard coagulation tests.Patients and methodsThis prospective observational study was performed among 41 patients with viper envenomation admitted to the Vietnam Poison Control Center from April 2016 to October 2017. Standard coagulation measurements [platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen level] and ROTEM indicators [clotting time (CT), amplitude (at set time: 5 and 10 minutes), clot information time (CFT) and maximum clot firmness (MCF) for extrinsic (EXTEM), intrinsic (INTEM), and fibrin based (FIBTEM) ROTEM] were obtained.ResultsFor INTEM, EXTEM, the FIBTEM, proportions of patients with prolonged CT were 34.1%, 63.4%, and 61.0% respectively and the proportions of patients with decreased MCF were 62.2%, 62.2%, and 35.5%, respectively. Moderate correlations were observed between PT and EXTEM CT (r = 0.627), aPTT and INTEM CT (r = 0.626), fibrinogen and FIBTEM MCF (r = 0.723), and platelet count and EXTEM MCF (0.60).ConclusionROTEM indicated a hypocoagulation state in patients with viper snakebite and was moderately correlated with standard coagulation parameters.     

Modified version of the American College of Cardiology's recommendation for low-dose prothrombin complex concentrate is effective for warfarin reversal

BackgroundDosing of four factor prothrombin complex concentrate (4PCC) for warfarin reversal remains controversial. Recently, the American College of Cardiology (ACC) recommended a low-dose PCC regimen as an option for warfarin reversal in acute major bleeding. We performed a retrospective study evaluating if a modified version of the ACC guideline recommendations was effective for warfarin reversal in acute major bleeds when compared to traditional variable dosing.MethodsThis was a retrospective cohort study of patients who received 4PCC for warfarin reversal in a 12 month period. We included patients that were ≥18 years of age, received 4PCC for warfarin reversal, and had an initial International Normalized Ratio (INR) of >2. Our primary outcome was the number of patients who had a post-4PCC infusion INR of <1.6.ResultsA total of 60 patients were included in the final analysis with 30 patients stratified to the traditional dosing and low-dose groups, respectively. Patient demographics were similar between both groups. We found no difference in the number of patients who had a post-4PCC infusion INR <1.6 between the traditional dosing and low dosing group (90.0% vs. 86.7%; p = 0.68). Additionally, we found no difference between post-infusion median INRs in each group (1.35 vs. 1.30; p = 0.16). Approximately 1000 units per patient were spared when utilizing the low-dose regimen.ConclusionA modified version of the ACC's low-dose 4PCC option for warfarin reversal achieves similar outcomes for lowering INR values compared to traditional variable dosing regimens.     

Effects of telavancin on coagulation test results

Background: The lipoglycopeptide antibiotic, telavancin, may interfere with some laboratory coagulation tests including prothrombin time (PT) and activated partial thromboplastin time (aPTT). Objective: To evaluate the effects of telavancin on PT and aPTT assays in common use. Methods: Pooled normal human plasma was spiked with telavancin 10, 20, 100 or 200 μg/ml (equivalent to trough, 2 × trough, peak and 2 × peak clinical plasma concentrations, respectively) or diluent control (0.9% sodium chloride). Samples were analysed using 16 PT reagents and seven aPTT reagents. Results: Telavancin 200 μg/ml (corresponding to 2 × peak clinical plasma concentration), produced significant PT prolongation (> 9% difference vs. diluent control) with all the 16 PT reagents (range 12% to > 600%). At lower telavancin concentrations, PT prolongation was dose‐dependent and varied among reagents, but appeared greatest with preparations containing recombinant tissue factor. With telavancin 10 μg/ml (equivalent to trough), PT prolongation was 10% with HemosIL^® PT‐Fibrinogen Recombinant, while ranging from 5% to –1% with all other reagents. Significant (> 34% difference vs. baseline) and dose‐dependent aPTT prolongation was observed with all the seven reagents in samples spiked with telavancin 100 or 200 μg/ml (range 65–142% at 200 μg/ml). aPTT reagents containing a silica activator appeared to be more sensitive to telavancin interference. Telavancin 10 μg/ml was not associated with increased aPTT with any of the reagents tested. Conclusions: Telavancin has the potential to prolong both PT and aPTT in vitro. It is recommended that samples for PT or aPTT be obtained just prior to a telavancin dose (trough).     

Thromboelastography (TEG®) compared to conventional coagulation tests in surgical patients – a laboratory evaluation

Abstract

Background. Several methods exist for evaluation of hypocoagulation in patients with perioperative bleeding, e.g. thromboelastography (TEG^®) and conventional methods (platelet count, aPTT, INR and fibrinogen). Considering the vast experience of conventional methods it is important to investigate how well the methods correspond. Methods. Sixty surgical patients were included prospectively and blood samples were taken perioperatively. TEG^® and conventional parameters were analyzed simultaneously. An assessment of coagulopathy, based on a synthesis of the conventional methods, was done by two experienced coagulation specialists, blinded from the results of TEG^® and from the results of each other. Hypocoagulation, defined by TEG^® parameters; reaction time (R-time), angle, maximal amplitude (MA) and fibrinolysis, was evaluated according to a commonly used algorithm. Results. To detect a platelet count below 150 × 10⁹ L^?1, the sensitivity of TEG was 17% (95% CI, 7–36%) with angle and 25% (95% CI, 11–45%) with MA. The sensitivity to detect fibrinogen below 2 g/L was 11% (95% CI, 3–29%) with angle and 21% with MA (95% CI, 8–43%). To detect aPTT more than 40 s and INR more than 1.2 with R-time, the sensitivity was 19% (95% CI, 8–37%) and 0% (95% CI, 0–69%) respectively. The agreement of the evaluator's assessments of hypocoagulation was 100%, but the agreement with the overall TEG^® analysis was poor with a sensitivity of 33% and a specificity of 95%. Conclusion. The agreement between conventional laboratory tests and TEG is poor, but it remains uncertain which type of coagulation tests that best reflects the actual bleeding risk.     

Effects of Vitamin D Supplementation on Bone Health and Bone-related Parameters in HIV-infected Patients: A Systematic Review and Meta-analysis

PurposeThere is growing evidence that bone health is decreased in individuals with HIV infection. Vitamin D deficiency is also highly prevalent among HIV-infected patients. The literature was systematically reviewed to determine whether bone health and bone-related parameters may improve with vitamin D supplementation in HIV-infected individuals.MethodsFour databases were systematically searched for randomized clinical trials of vitamin D supplementation in HIV infection, published from January 1990 to September 2021. No language or publication restrictions were applied. Standardized mean differences (SMD) with 95% CIs are reported. A random-effects model was used to perform meta-analysis.FindingsTen studies met the inclusion criteria (N = 733 participants at study completion). The mean ages of the patients in the included trials ranged from 10 to 49 years. The meta-analysis indicated that with vitamin D supplementation, serum 25-hydroxy vitamin D (25[OH]D) level was significantly increased (SMD, 1.86; 95% CI, 1.02 to 2.70; I² = 94.4%), but there were no significant effects on levels of serum 1,25-dihydroxy vitamin D (1,25-[OH]₂D) (SMD, 0.29; 95% CI, –0.07 to 0.64; I² = 67.4%), total bone mineral density (SMD, 0.07; 95% CI, –0.23 to 0.37; I² = 00.0%), spine bone mineral density (SMD, 0.15; 95% CI, –0.19 to 0.49; I² = 17.3%), and parathyroid hormone level (SMD, –0.18; 95% CI, –0.37 to 0.02; I² = 1.2%) in HIV-infected patients.ImplicationsThis study showed that vitamin D supplementation can improve serum 25(OH)D in HIV-infected patients. The effects of vitamin D supplementation on other bone health–related parameters such as bone mineral density and parathyroid hormone in HIV-infected patients need to be further investigated in larger-scale, well-designed randomized, controlled trials.     

The 5, 10 methylenetetrahydrofolate reductase C677T mutation and risk of fetal loss: a case series and review of the literature

Recommendations for urgent reversal of oral anticoagulation with vitamin K₁ antagonists are largely derived from case series employing empirical dosing regimens with vitamin K₁ and prothrombin complex concentrates. Data on the use of prothrombin complex concentrates in this indication are scarce in the elderly who are at high risk of both hemorrhagic and thrombotic complications. The two cases presented here describe patients older than 75 years who underwent rapid International Normalized Ratio (INR) reversal with prothrombin complex concentrates for surgical treatment of a bleeding ruptured spleen and for emergency surgery of a dissecting aorta. Both patients had their INRs rapidly corrected to ≤ 1.6 and underwent operation without complications. Evidence on treatment of patients who present with elevated INR and who have major bleeding or need to undergo emergency surgery is based mainly on observational studies. The two elderly patients presented here underwent successful emergency surgery after their INRs had been corrected with the intravenous use of vitamin K₁ in combination with prothrombin complex concentrate that was administered according to current guideline recommendations.     

Use of error grid analysis to evaluate acceptability of a point of care prothrombin time meter

BackgroundStatistical methods (linear regression, correlation analysis, etc.) are frequently employed in comparing methods in the central laboratory (CL). Assessing acceptability of point of care testing (POCT) equipment, however, is more difficult because statistically significant biases may not have an impact on clinical care. We showed how error grid (EG) analysis can be used to evaluate POCT PT INR with the CL.Materials and methodsWe compared results from 103 patients seen in an anti-coagulation clinic that were on Coumadin maintenance therapy using fingerstick samples for POCT (Roche CoaguChek XS and S) and citrated venous blood samples for CL (Stago STAR). To compare clinical acceptability of results we developed an EG with zones A, B, C and D.ResultsUsing 2nd order polynomial equation analysis, POCT results highly correlate with the CL for CoaguChek XS (R² = 0. 955) and CoaguChek S (R² = 0. 93), respectively but does not indicate if POCT results are clinically interchangeable with the CL. Using EG it is readily apparent which levels can be considered clinically identical to the CL despite analytical bias.ConclusionWe have demonstrated the usefulness of EG in determining acceptability of POCT PT INR testing and how it can be used to determine cut-offs where differences in POCT results may impact clinical care.     

The short-term effects of balneotherapy on pain,disability and fatigue in patients with chronic low back pain treated with physical therapy: A randomized controlled trial

ObjectiveThis study aimed to compare whether there are positive effects of balneotherapy(BT) on pain, quality of life and disability of individuals receiving physical therapy(PT) for chronic low back pain and to examine the effect of body mass index(BMI) on treatment.Materials and methodThis prospective, controlled, single blind study was conducted. Patients were randomized into two groups through a simple randomization in a 1:1 ratio. The clinician and biostatistics expert were blinded. PT group was applied PT, BT + PT group was applied PT + BT. All patients were included in the study for 3 weeks (total of 15 sessions, 5 days per week). All patients applied hot pack, transcutaneous electrical nerve stimulation and ultrasound. Patients in the BT + PT group applied BT in thermo mineralized water pool (20 min at 38−40 °C). Assessments were made using Pain-Visual Analog Scale(VAS), EQ-5D-3 L Scale(EQ5), EQ-VAS, Functional Assessment of Chronic Illness Therapy-Fatigue(FACIT-F), Roland-Morris Disability Questionnaire(RMDQ) and Quebec Back Pain Disability Scale(QBPDS) at the beginning (W0) and end (W3) of treatment. While performing statistical analysis, patients were divided into 3 categories of BMI1(18.5–24.9 kg/m²), BMI2 (25.0–29.9 kg/m²) and BMI3(≥30.0 kg/m²).Results270 patients were randomized. 129 patients in PT group and 133 patients in PT + BT group completed the study. In the BT + PT group, there were increases in the EQ5 and EQ-VAS variables and decreases in all other variables compared to the PT group which were found to be statistically significant (for QBPDS p < 0.05, the others p < 0.01). The differences in all variables W0 and W3 were at least half reductions and increases which were found to be statistically significant (p < 0.01). In terms of BMI, there were significant differences for all groups, especially BMI3 had higher means for all variables apart from EQ5 and EQ-VAS than the other two categories. BMI1 was the BMI category with highest means for EQ5 and EQ-VAS. The Group × Time interaction was found to be statistically significant for Pain-VAS, EQ5, EQ-VAS, FACIT-F, QBPDS and RMDQ(p < 0.01). For Pain-VAS, the effect of the Group × Time × BMI interaction was found to be statistically significant(p < 0.05).ConclusionBT plus PT was more effective than PT. BT may have positive contributions to reducing pain, functionality of patients, quality of life, fatigue and disability status.     

The agreement between capillary and venous sampling for plasma PT/INR results

Abstract

Regular measurement of prothrombin time (PT) as an international normalized ratio (INR) is of great importance in ensuring a safe Warfarin treatment due to the narrow therapeutic range. Hence, accurate results of the PT/INR analysis are crucial. Due to the high sampling load that patients on Warfarin experience, some prefer capillary sampling (from the tip of the finger) as an alternative to standard venous sampling (from the cubital fossa). The present study evaluated the method of capillary sampling compared to the standard venous method for plasma PT/INR measurement. Both venous and capillary samples were collected simultaneously for plasma PT/INR testing from 100 patients of which the majority undergoing active Warfarin treatment. The samples were analyzed on a Sysmex 2100i instrument (Siemens) using the Owrens method with PT reagents from MediRox. The capillary sampling method showed statistically significant lower values (p?相似文献   

Assessment of thrombin generation measured before and after cardiopulmonary bypass surgery and its association with postoperative bleeding

Summary. Background: Bleeding after cardiopulmonary bypass (CPB) is a major cause of morbidity and mortality and consumes large amounts of blood. Identifying patients at increased risk of bleeding secondary to hemostatic impairment may improve clinical outcomes by allowing early intervention. Methods: This present study recruited 77 patients undergoing CPB and measured coagulation screens, coagulation factors, TEG^®, Rotem^® and thrombin generation (TG) before surgery and 30 min after heparin reversal. The tests were analyzed to investigate whether they identified patients at increased risk of excess bleeding (defined as > 1000 mL) in the first 24 h postoperatively. Results: Patients who bled > 1000 mL had a lower: platelet count (P < 0.02), factors (F)IX, X and XI (P < 0.005), endogenous thrombin potential (ETP) and an initial rate of TG (P < 0.02) and higher activated partial thromboplastin time (aPTT) (P < 0.001) than patients who bled < 1000 mL. Receiver operating characteristic (ROC) analysis was significant for post‐operative TG and aPTT (P < 0.001). Furthermore, reduced pre‐operative TG was associated with increased postoperative bleeding (P < 0.02). Pre‐ and postoperative TG were correlated (ρ = 0.7, P < 0.001). TEG^®, Rotem^® and prothrombin time (PT) at either time point were not associated with increased bleeding. Conclusion: These data suggest that pre‐operative defects in the propagation phase of hemostasis are exacerbated during CPB, contributing to bleeding post‐CPB. TG taken both pre‐ and postoperatively could potentially be used to identify patients at an increased risk of bleeding post‐CPB.     

Warfarin Poisoning with Delayed Rebound Toxicity

Background

Intentional poisoning with warfarin is not the same as over-anticoagulation, for which guidelines exist. The coagulopathy resulting from a warfarin overdose is reversed with vitamin K₁, the dose and timing of which is often guided by experience with the management of over-anticoagulation with warfarin therapy, rather than acute overdose.

Coagulation defects in trauma patients: etiology, recognition, and therapy

Trauma patients have many reasons to have defects in coagulation. These can be caused by the trauma or because of pre-existing disorders. Trauma patients who are at risk for coagulation defects should be screened with the basic tests (aPTT, INR/PT, platelet counts, hematocrit, and fibrinogen), with therapy based on the results. Attention also should be paid to any other correctable factors such as hypothermia. Finally, pre-existing disorders can influence the patient's hemostasis greatly and may require specific therapies.