Thrombelastography Values Research Articles

Empiric Cryoprecipitate Transfusion in Patients with Severe Hemorrhage: Results from the US Experience in the International CRYOSTAT-2 Trial.

Hypofibrinogenemia has been shown to predict massive transfusion and is associated with higher mortality in severely injured patients. However, the role of empiric fibrinogen replacement in bleeding trauma patients remains controversial. We sought to determine the effect of empiric cryoprecipitate as an adjunct to a balanced transfusion strategy (1:1:1). This study is a subanalysis of patients treated at the single US trauma center in a multicenter randomized controlled trial. Trauma patients (more than 15 years) were eligible if they had evidence of active hemorrhage requiring emergent surgery or interventional radiology, massive transfusion protocol (MTP) activation, and received at least 1 unit of blood. Transfer patients, those with injuries incompatible with life, or those injured more than 3 hours earlier were excluded. Patients were randomized to standard MTP (STANDARD) or MTP plus 3 pools of cryoprecipitate (CRYO). Primary outcomes included all-cause mortality at 28 days. Secondary outcomes were transfusion requirements, intraoperative and postoperative coagulation laboratory values, and quality-of-life measures (Glasgow outcome score-extended). Forty-nine patients (23 in the CRYO group and 26 in the STANDARD group) were enrolled between May 2021 and October 2021. Time to randomization was similar between groups (14 vs 24 minutes, p = 0.676). Median time to cryoprecipitate was 41 minutes (interquartile range 37 to 48). There were no differences in demographics, arrival physiology, laboratory values, or injury severity. Intraoperative and ICU thrombelastography values, including functional fibrinogen, were similar between groups. There was no benefit to CRYO with respect to post-emergency department transfusions (intraoperative and ICU through 24 hours), complications, Glasgow outcome score, or mortality. In this study of severely injured, bleeding trauma patients, empiric cryoprecipitate did not improve survival or reduce transfusion requirements. Cryoprecipitate should continue as an "on-demand" addition to a balanced transfusion strategy, guided by laboratory values and should not be given empirically.

Green Plasma Has a Superior Hemostatic Profile Compared With Standard Color Plasma.

Limitations in available donors have dramatically reduced plasma availability over the past several decades, concurrent with increasing demand for some types of plasma. Plasma from female donors who are pregnant or taking oral contraceptives often has a green appearance, which frequently results in these units being discarded. This pilot study aimed to evaluate the hemostatic potential of green compared to standard-color plasma. Plasma from twelve blood group-matched female and twelve male donors was obtained from the local blood center. Six of the female and all of the male units of plasma had a normal appearance (STANDARD), while six of the female units were grossly green (GREEN). The hemostatic potential was evaluated by thrombelastography (TEG), calibrated automated thrombogram (CAT), and coagulation factor level measurements. Univariate analysis was performed using Wilcoxon Rank-Sum. GREEN plasma was more procoagulant for all TEG values (r-value, k-time, angle, mA) when compared to STANDARD plasma. Differences were also observed in coagulation factor levels, with GREEN plasma having higher than STANDARD (factors II; VII, IX; X, XI, Protein S, and plasminogen); conversely, GREEN plasma had a longer lag time in CAT. This pilot study demonstrates that female donors with green plasma have a superior hemostatic profile than standard plasma. GREEN plasma should be further investigated for its safety profile and hemostatic potential, so if it is found to be a safe and functionally non-inferior product, it should be actively re-introduced for transfusion in bleeding patients.

Does subcutaneous administration of recombinant human erythropoietin increase thrombotic events in total hip arthroplasty? A prospective thrombelastography analysis

BackgroundAnemia is one of severe complications in the perioperative period of total hip arthroplasty (THA). Erythropoietin (EPO) has been considered to improve patients’ anemia state, but its efficiency and safety remains controversial.MethodsA total of 152 patients who underwent total hip arthroplasty from January 2017 to March 2019 were randomized to 2 groups. Recombinant human erythropoietin (rHu-EPO) group was treated with rHu-EPO subcutaneous injection 10000 IU after operation and once daily in the next week, while control group was treated with none extra treatment. Routine hematologic examination and thrombelastography (TEG) performed at different time point respectively. Doppler ultrasound for bilateral lower limbs was performed 1 day before surgery and 7 days after surgery. Auxiliary examination outcomes, blood transfusions outcomes, and postoperative complications were recorded as assessment indicators.ResultsThe difference in the relevant indexes of traditional coagulation and TEG values between two groups were not significantly. No significant difference was observed in the incidence of thromboembolism events and other complications between two groups during postoperative period. The amount of intraoperative blood loss was similar between the two groups. However, the postoperative use and dosage of allogeneic blood in the rHu-EPO group were lower than those in the control group. The hemoglobin and hematocrit level in the rHu-EPO group were higher than that in the control group after surgery.ConclusionPostoperative subcutaneous injection of rHu-EPO can improve hematological anemia-related parameters, reduce the use and dosage of allogeneic blood transfusions (ABTs), and has no significant influence on the formation of thrombosis and other complications in patients undergoing total hip arthroplasty in short term.

Perioperative thrombelastography serves as an important assessment tool of transfusion requirements during liver transplantation

BackgroundThrombelastography has become increasingly used in liver transplantation. The implications of thrombelastography at various stages of liver transplantation, however, remain poorly understood. Our goal was to examine thrombelastography-based coagulopathy profiles in liver transplantation and determine whether preoperative thrombelastography is predictive of transfusion requirements perioperatively. MethodsA retrospective review of 364 liver transplantations from January 2013 to May 2017 at a single institution was performed. Patients were categorized as hypocoagulable or nonhypocoagulable based on their preoperative thrombelastography profile. The primary outcome was intraoperative transfusion requirements. ResultsOf patients undergoing liver transplantation, 47% (n = 170) were hypocoagulable and 53% (n = 194) were nonhypocoagulable preoperatively. Hypocoagulable patients had higher transfusion requirements compared to nonhypocoagulable patients, requiring more units of packed red blood cells (7 vs 4, P < .01), fresh frozen plasma (14 vs 8, P < .01), cryoprecipitate (2 vs 1, P < .01), platelets (3 vs 2, P < .01), and cell saver (3 vs 2 L, P < .01). Additionally, these patients were more likely to receive platelets and cryoprecipitate in the first 24 hours following liver transplantation (both P < .05). No differences were found between rates of intensive care unit length of stay, 30-day readmission, or mortality. ConclusionCoagulation abnormalities are common among liver transplantation patients and can be identified using thrombelastography. Identification of a patient's coagulation state preoperatively aids in guiding transfusion during liver transplantation. This work serves to better direct clinicians during major surgery to improve perioperative resource utilization. Future prospective work should aim to identify specific thrombelastography values that may predict transfusion requirements.

Thrombelastography early amplitudes in bleeding and coagulopathic trauma patients: Results from a multicenter study.

Early amplitudes in the viscoelastic hemostatic assays, thrombelastography (TEG) and rotation thromboelastometry (ROTEM), provide fast results, which is critical in the resuscitation of bleeding patients. This study investigated associations between TEG early amplitudes and standard TEG variables in a large multicenter cohort of moderately to severely injured trauma patients admitted at three North European Level I Trauma Centers. Prospective observational study of 404 trauma patients with clinical suspicion of severe injury from London, UK, Copenhagen, Denmark and Oslo, Norway. Biochemistry and clinical data including outcome and TEG parameters were recorded upon arrival. Kaolin TEG, Rapid TEG, and TEG functional fibrinogen curves were extracted, and early amplitudes A5 and A10 (amplitude at 5 and 10 minutes) were registered. Patients were stratified according to international normalized ratio of 1.2 or less or greater than 1.2, as well as transfusion requirements (nontransfused, 1-9 red blood cell units and ≥10 red blood cell units in 12 hours). In total, 404 patients were included, median Injury Severity Score was 13. There were strong positive correlations between A5/A10 and maximum amplitude in all investigated assays. All TEG values except rTEG maximum amplitude and kTEG maximum amplitude correlated significantly with mortality in transfused patients. Time from initiation of assay to A5 and A10 were lowest for rapid TEG and TEG functional fibrinogen compared with kaolin TEG. Rapid TEG A5 reduced time to result with greater than 50% compared with rapid TEG maximum amplitude. We found strong associations between TEG early amplitudes A5/A10 and maximum amplitude in rapid TEG, kaolin TEG, and TEG functional fibrinogen across trauma patients with coagulopathy and massive transfusion requirements. Introducing the use of early amplitudes can reduce time to diagnosis of coagulopathy and may be used in TEG monitoring of trauma patient. Further randomized controlled trials evaluating the role of TEG in guiding hemostatic resuscitation are warranted. Prognostic study, level III.

The hyperfibrinolytic phenotype is the most lethal and resource intense presentation of fibrinolysis in massive transfusion patients.

Among bleeding patients, we hypothesized that the hyperfibrinolytic (HF) phenotype would be associated with the highest mortality, whereas shutdown (SD) patients would have the greatest complication burden. Severely injured patients predicted to receive a massive transfusion at 12 Level I trauma centers were randomized to one of two transfusion ratios as described in the Pragmatic, Randomized, Optimal Platelet and Plasma Ratio trial. Fibrinolysis phenotypes were determined based on admission clot lysis at 30 minutes (LY30): SD ≤0.8%, physiologic (PHYS) 0.9-2.9%, and HF ≥3%. Univariate and multivariate analysis was performed. Logistic regression was used to adjust for age, gender, arrival physiology, shock, injury severity, center effect, and treatment arm. Among the 680 patients randomized, 547(80%) had admission thrombelastography (TEG) values available to determine fibrinolytic phenotypes. Compared to SD and PHYS, HF patients had higher Injury Severity Score (25 vs. 25 vs. 34), greater base deficit (-8 vs. -6 vs. -12) and were more uniformly hypocoagulable on admission by PT, PTT, and TEG values; all p <0.001. HF patients also received more red blood cells, plasma, and platelets (at 3, 6, and 24 hours); had fewer ICU-, ventilator-, and hospital-free days; and had higher 24-hour and 30-day mortality. There were no differences in complications between the three phenotypes. Multivariate logistic regression demonstrated that HF on admission was associated with a threefold higher mortality (OR 3.06, 95% CI 1.57-5.95, p = 0.001). Previous data have shown that both the SD and HF phenotypes are associated with increased mortality and complications in the general trauma population. However, in a large cohort of bleeding patients, HF was confirmed to be a much more lethal and resource-intense phenotype. These data suggest that further research into the understanding of SD and HF is warranted to improve outcomes in this patient population. Prognostic, level II.

Dual Antiplatelet Therapy Is Associated With Coagulopathy Detectable by Thrombelastography in Acute Stroke.

Thrombelastography (TEG) provides a global, dynamic measure of coagulation. We examined the effect of antiplatelet (AP) medications on coagulation in patients with acute stroke as measured by TEG. We reviewed prospectively collected data on patients presenting with acute ischemic stroke (AIS) and spontaneous intracerebral hemorrhage (ICH) between 2009 and 2014. Patient demographics and baseline TEG values were compared among 4 different drug use groups: aspirin only, clopidogrel only, both aspirin and clopidogrel, and no AP. Multivariable regression models were conducted to compare the differences in TEG components. A total of 202 patients were included, 139 with AIS and 63 with ICH. Forty-eight (24%) patients were taking aspirin alone, 12 (6%) were taking clopidogrel, 16 (8%) dual AP, and 126 (62%) no AP. Dual AP use was associated with prolonged mean R (time to initiate clotting) of 5.5 minutes as compared to no AP use (4.6 minutes, P = .04). Additionally, mean maximal amplitude (MA; final clot strength) and angle (rate of clot formation) were decreased in the dual AP group (MA = 59.3 mm, angle = 57.8°) as compared to the no AP group (MA = 64.5 mm, angle = 64.5°; P = .04 and P = .01, respectively). Patients on single AP therapy (either aspirin or clopidogrel) did not differ from those on no AP therapy in any TEG parameters measured. Dual AP therapy is associated with a detectable coagulopathy which may have implications in the management of patients with AIS and hemorrhagic stroke. The effects of single AP therapy may not be demonstrated by TEG.

Prevalence and Impact of Admission Acute Traumatic Coagulopathy on Treatment Intensity, Resource Use, and Mortality: An Evaluation of 956 Severely Injured Children and Adolescents

Acute coagulopathy of trauma in children is of potential importance to clinical outcomes, but knowledge is limited and has only been investigated using conventional coagulation testing. The purpose of this study was to assess the prevalence and impact of arrival coagulopathy, determined by viscoelastic hemostatic testing, in severely injured children. Pediatric patients (younger than 17 years of age) who were admitted January 2010 to May 2016 and met highest-level trauma activation were included. Patients were divided into 2 groups (coagulopathy and controls) based on arrival rapid thrombelastography values. Coagulopathy was defined as the presence of any of the following on rapid thrombelastography: activated clotting time ≥128 seconds, α-angle ≤65 degrees, maximum amplitude ≤55mm, and lysis at 30 minutes from 20-mm amplitude ≥3%. Logistic regression was used to adjust for age, sex, blood pressure, mechanism, and injury severity. Nine hundred and fifty-six patients met inclusion; 507 (57%) were coagulopathic and 449(43%) were not (noncoagulopathic and control cohort). Coagulopathic patients were younger (median 14 vs 15 years) and more likely to be male (68% vs 60%) and Hispanic (38% vs 31%) (all p < 0.05). Coagulopathic patients received more RBC and plasma transfusions and had fewer ICU and ventilator-free days and higher mortality (12% vs 3%; all p < 0.05). Of these 956, 197 (21%) sustained severe brain injury-123 (62%) were coagulopathic and 74 (38%) were noncoagulopathic. The mortality difference was even greater for coagulopathic head injuries (31% vs 10%; p= 0.002). Adjusting for confounders, admission coagulopathy was an independent predictor of death, with an odds ratio of 3.67(95% CI 1.768 to 7.632; p < 0.001). Almost 60% of severely injured children and adolescents arrive with evidence of acute traumatic coagulopathy. The presence of admission coagulopathy is associated with high mortality in children, especially among those with head injuries.

Splenectomy is associated with hypercoagulable thrombelastography values and increased risk of thromboembolism

Previous investigators have demonstrated that postinjury thrombocytosis is associated with an increase in thromboembolic (TE) risk. Increased rates of thrombocytosis have been found specifically in patients after splenectomy for trauma. We hypothesized that patients undergoing splenectomy (1) would demonstrate a more hypercoagulable profile during their hospital stay and (2) that this hypercoagulable state would be associated with increased TE events. This was a 14-month, prospective, observational trial evaluating serial rapid thrombelastography (rTEG) at 3 American College of Surgeons-verified, level 1 trauma centers. Inclusion criteria were highest-level trauma activation and arrival within 6hours of injury. Exclusion criteria were <18years of age, incarcerated, and burns>20% total body surface area. Serial rTEG (activated clotting time, k-time, α-angle, MA, lysis) and traditional coagulation testing (prothrombin time, partial thromboplastin time, fibrinogen and platelet count) were obtained at admission and then at 3, 6, 12, 24, 48, 72, 96, and 120hours. Thromboembolic complications were defined as the development of deep-vein thrombosis, pulmonary embolism, acute myocardial infarction, or ischemic stroke during hospitalization. Patients were stratified into splenectomy versus nonsplenectomy cohorts. Univariate analysis was then conducted followed by longitudinal analysis using generalized estimating equations to evaluate the effects of time, splenectomy, and group-time interactions on changes in rTEG and traditional coagulation testing. We used an adjusted generalized estimating equation model to control for age, sex, ISS, admission blood pressure, base deficit, and hemoglobin. A total of 1,242 patients were enrolled; 795 had serial rTEG data. Of these, 605 had serial values >24hours and made up the study population. Splenectomy patients were younger, more hypotensive, and in shock on arrival. Although there was no difference in 24-hour or 30-day mortality, splenectomy patients were more likely to develop TE events. Using the GEE model, we found that α-angle and MA in splenectomy patients were lesser (more hypocoagulable) within the first 6hours; however, they became substantially greater (more hypercoagulable) at 48, 72, 96, and 120hours; all P<.05. In addition, platelet counts were greater in the splenectomy group beginning at 72hours and continuing through 120hours; P<.05. This multicenter, prospective study demonstrates that patients undergoing splenectomy have a more hypercoagulable state than other trauma patients. This hypercoagulable state (identified by greater α-angle and mA values) begins at approximately 48hours after injury and continues through at least day 5. Moreover, this hypercoagulable state is associated with increased risk of TE complications.

Abstract T P321: Thrombelastography Can Detect Differences In Patients With Intracerebral Hemorrhage With And Without Intraventricular Hemorrhage

Background: Intraventricular hemorrhage (IVH) is an important variable for predicting outcomes in patients with intracerebral hemorrhage (ICH). Thrombelastography (TEG) analyzes the dynamics of coagulation (Figure 1) and has previously demonstrated a hypercoagulable state in patients with acute ischemic stroke. Less is known about TEG and patients with ICH, especially those associated with IVH. We sought to determine whether TEG can detect differences between patients with ICH with and without IVH. Methods: Venous blood of patients with spontaneous ICH was analyzed with TEG. Demographics and baseline TEG values were compared between patients with and without IVH on initial CT scan. Multivariable linear regression models were conducted to compare the differences in TEG components between the two groups after adjusting for potential confounders. Results: Sixty-nine patients with ICH (32 with IVH, 37 without IVH) were analyzed. Baseline antiplatelet use, platelet count, coagulation studies (PT/PTT), and hematoma volume were similar between the two groups. Increased R time (table 1) was seen in patients with IVH (R=4.9) compared to those without IVH (R=4.0, p=0.04), indicating increased time to clot formation. No differences were observed in other baseline TEG values. Conclusion: TEG can detect differences in the coagulation profile of ICH patients with and without IVH. ICH patients with IVH have a coagulopathy detectable by TEG independent of antiplatelet or anticoagulant use. TEG may be valuable in the control of hemostasis in patients with ICH.

Positive blood alcohol is associated with reduced DVT in trauma

IntroductionTrauma patients exhibit a complex coagulopathy which is not fully understood and deep venous thrombosis (DVT) rates remain high. The effects of alcohol (EtOH) consumption on coagulopathy in trauma patients have not been studied. We hypothesized that acute EtOH intoxication would produce a relative hypocoagulable state as measured by thrombelastography (TEG) and would be associated with reduced DVT rates. MethodsData were prospectively collected on 213 trauma patients at a level 1 trauma centre and analyzed in a retrospective secondary analysis. Thrombelastography (TEG), standard laboratory tests and ETOH levels were performed. If the level was positive, patients were grouped as EtOH+ and all patients were screened for DVT using a standard protocol. Statistical significance was p<0.05. ResultsThe EtOH+ group was predominantly male (76%), was younger (p<0.05), had a lower BMI (p<0.05), demonstrated a lower AIS extremity score (p<0.01) and was less likely to have a blunt injury (p<0.01) than the EtOH− group. Gender, ISS and other AIS scores were not significantly different. TEG values in the alcohol group demonstrated a relative hypocoagulable state that was associated with a reduced DVT incidence, 1.4% versus 16.2%, (p<0.01). This difference was not detected with conventional assays. A multivariate logistic regression was performed, controlling for common risk factors for DVT and a positive EtOH level on admission was independently associated with reduced DVT incidence. ConclusionsAlcohol consumption is associated with a relative hypocoagulable state on TEG that is associated with a decreased DVT incidence. This difference is not detected by conventional assays.

A principal component analysis of postinjury viscoelastic assays: Clotting factor depletion versus fibrinolysis

The mechanisms driving trauma-induced coagulopathy (TIC) remain to be defined, and its therapy demands an orchestrated replacement of specific blood products. Thrombelastography (TEG) is a tool to guide the TIC multicomponent therapy. Principal component analysis (PCA) is a statistical approach that identifies variable clusters; thus, we hypothesize that PCA can identify specific combinations of TEG-generated values that reflect TIC mechanisms. Adult trauma patients admitted from September 2010 to October 2013 for whom a massive transfusion protocol was activated were included. Rapid TEG values obtained within the first 6hours after injury were included in the PCA. PCA components with an eigenvalue >1 were retained, and, within components, variable loadings (equivalent to correlation coefficients) >|60| were considered significant. Component scorings for each patient were calculated and clinical characteristics of patients with high and low scores were compared. Of 98 enrolled patients, 67% were male and 70% suffered blunt trauma. Median age was 41years (interquartile range 28-55) and median Injury Severity Score was 31.5 (interquartile range 24-43). PCA identified three principal components (PCs) that together explained 93% of the overall variance. PC1 reflected global coagulopathy with depletion of platelets and fibrinogen whereas PC3 indicated hyperfibrinolysis. PC2 may represent endogenous anticoagulants such as the activation of protein C. PCA suggests depletion coagulopathy is independent from fibrinolytic coagulopathy. Furthermore, the distribution of mortality suggests that low levels of fibrinolysis may be beneficial in a select group of injured patients. These data underscore the potential of risk for concurrent presumptive treatment for preserved depletion coagulopathy and possible fibrinolysis.

Systematic evaluation of evidence on veterinary viscoelastic testing Part 5: Nonstandard assays

To systematically examine the evidence on nontraditional uses of viscoelastic coagulation monitoring in veterinary species. Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality, and development of consensus on conclusions for application of the concepts to clinical practice. Academic and referral veterinary medical centers. Databases searched included Medline, CAB abstracts, and Google Scholar. Nontraditional assays identified included thrombelastography (TEG)-PlateletMapping (PM), functional fibrinogen assessment, and rapid-TEG (r-TEG). Direct veterinary evidence was found for only the ADP-activated PM, which appears to generate valid data in dogs but not cats or horses. Arachidonic acid activated PM shows high variability and requires further assessment and validation in veterinary species. Functional fibrinogen assays may be performed in veterinary species but may require modification due to species differences in response to abciximab. While tissue factor (TF)-activated TEG has been well described in the veterinary literature, the specific r-TEG assay has not been assessed, but presumably would be effective for generating TEG tracings and values for maximum amplitude and angle in shorter periods of time than some traditional assays.

The International Normalized Ratio overestimates coagulopathy in stable trauma and surgical patients

The international normalized ratio (INR) was developed to assess adequacy of Coumadin dosing. Its use has been generalized to guide fresh frozen plasma (FFP) therapy in stable patients. Thrombelastography (TEG) is a whole-blood assay measuring the viscoelastic properties of the clot in near real time. This study hypothesized that INR does not reflect coagulopathy and should not be used to guide FFP therapy in stable trauma and surgical patients. Prospective observational data were collected from stable trauma and surgical patients (n = 106) who received FFP transfusions. Pretransfusion and posttransfusion blood samples were obtained to assess complete blood count, standard coagulation parameters (INR, partial thromboplastin time, fibrinogen and D-dimer), soluble clotting factors (II, V, VII, VIII, IX, X, XI, XII, proteins C and S) and TEG. Data were analyzed using a Mann-Whitney U-test. Significance was defined as p < 0.05. A total of 262 U of FFP were transfused, with 78% of 106 patients receiving two or more units. Despite a reduction in INR, median TEG values remained within normal limits, while clotting factor levels retained adequate function to produce normal clotting before and following FFP transfusion. The use of FFP in this population did not affect coagulation status in a clinically relevant manner based on TEG values and coagulation factor function. INR is not a predictor of coagulopathy and should not be used to guide coagulation factor replacement in stable trauma and surgical patients. Diagnostic study, level III.

Fibrinogen function is impaired in whole blood from patients with cyanotic congenital heart disease

BackgroundPatients with cyanotic congenital heart disease (CCHD) have haemostatic abnormities associated with bleeding and thrombo-embolic events. The haemostatic abnormalities are not fully understood, but recent studies indicate that elevated haematocrit and fibrinogen function may be of importance.The aim of this study was to characterise the haemostatic profile and examine the potential role of haematocrit on clot formation and strength in CCHD patients. Furthermore to examine whether CCHD patients with history of haemoptysis have diminished fibrinogen function compared to those without haemoptysis. MethodsIn a prospective study 75 adult CCHD patients had haematocrit, platelet count, and plasma fibrinogen concentration examined. Furthermore thrombelastography(TEG) as well as TEG Functional Fibrinogen(TEG FF) assay evaluating fibrinogen function(FLEV) was performed. Data were compared with historical data regarding previous haemoptysis in CCHD patients. ResultsHaematocrit was 57±8% and platelet counts in the lower normal range. TEG revealed a hypocoagulable condition with impaired clot formation. TEG values were correlated to haematocrit, indicating that elevated haematocrit causes impaired clot formation and strength. Despite high levels of plasma fibrinogen, TEG FF demonstrated that FLEV was diminished and negatively correlated to haematocrit. Furthermore CCHD patients with previous history of haemoptysis had significantly lower FLEV compared to CCHD patients without haemoptysis. ConclusionPatients with CCHD are hypocoagulable mainly due to impaired fibrinogen function. Despite a low platelet count, platelet function does not seem to be severely affected in CCHD patients. Haemostasis, and especially fibrinogen function, is negatively affected by elevated haematocrit, and fibrinogen function is diminished in CCHD patients with haemoptysis.

A Reduction in Clot Formation Rate and Strength Assessed by Thrombelastography Is Indicative of Transfusion Requirements in Patients With Penetrating Injuries

Bleeding is a major cause of death in patients with traumatic injuries. Recently, thrombelastography (TEG) has been suggested as an additional means of evaluating coagulation in trauma patients. We hypothesized that TEG data would aid in defining the coagulopathy of trauma in patients with penetrating traumatic injuries. A retrospective study was performed of patients (n = 44) with penetrating injuries admitted to a combat support hospital during a 2-month period in 2004. Recorded data included standard laboratory data, TEG parameters, and blood product use in the first 24 hours after admission. Values were compared with clinically accepted ranges and those obtained from the Haemoscope Corporation. At admission, International Normalization Ratio, prothrombin time, and partial thromboplastin time were increased in 39% (>or=1.5), 31% (>16 seconds), and 37% (>40 seconds) of patients, respectively, suggesting hypocoagulation, but these variables did not correlate with the use of blood products (p > 0.05). TEG values obtained within 24 hours of admission (6 hours +/- 5.7 hours; median of 4.5 hours) demonstrated hypocoagulation based on delayed propagation of the clot (increased K time and reduced alpha-angle) and decreased clot strength (reduced maximal amplitude [MA]). MA correlated (r = 0.57, p < 0.01) with blood product use as well as platelet count (r = 0.61, p < 0.01). Patients with reduced MA (n = 23) used more blood products and had reduced platelet counts and hematocrit. Thrombelastography was a more accurate indicator of blood product requirements in our patient population than prothrombin time, partial thromboplastin time, and International Normalization Ratio. Thrombelastography enhanced by platelet count and hematocrit can guide blood transfusion requirements.

Effects of albumin 5% and artificial colloids on clot formation in small infants

Albumin is often cited in textbooks as the gold standard for fluid replacement in paediatrics, but in practice artificial colloids are more frequently used. Although one concern with the use of artificial colloids is their intrinsic action on haemostasis, the available data in children are inconclusive for 6% hydroxyethyl starch 130/0.4 (HES) and no data exist for gelatine solution with respect to coagulation. A total of 42 children (3-15 kg) undergoing surgery and needing colloid replacement were randomly assigned to receive 15 mlxkg(-1) of either albumin 5%, 4% modified gelatine solution or 6% hydroxyethyl starch 130/0.4 solution. Standard coagulation tests and modified thrombelastography (ROTEM) were performed. After colloid administration, routine coagulation test results changed significantly and comparably in all groups, although activated partial thromboplastin time values increased more with gelatine and HES. Coagulation time was unchanged in the children who received albumin or gelatine but other activated modified thrombelastography values were significantly impaired in all groups. After gelatine and after albumin the median clot firmness decreased significantly but remained within the normal range. Following HES, coagulation time increased significantly, and clot formation time, alpha angle, clot firmness, and fibrinogen/fibrin polymerisation were significantly more impaired than for albumin or gelatine, reaching median values below the normal range. From a haemostatic point of view it might be preferable to use gelatine solution as an alternative to albumin; HES showed the greatest effects on the overall coagulation process.

A Single Bolus of 3% Hypertonic Saline with 6% Dextran Provides Optimal Initial Resuscitation After Uncontrolled Hemorrhagic Shock

The optimal fluid for early resuscitation of hemorrhagic shock would restore perfusion without increasing blood loss, hypothermia, acidosis, or coagulopathy. This study examined effects of a single bolus of hypertonic saline (HTS) with or without (+/-) dextran (D) after uncontrolled hemorrhage (UH) and determined optimal fluid composition. Fifty swine were anesthetized and underwent invasive line placement, celiotomy, splenectomy, suprapubic catheterization, and grade V liver injury. After 30 minutes of UH, blinded fluid resuscitation was initiated with a 250-mL bolus. Animals were randomized to five groups: normal saline (NS), 3% HTS (3%), 3% HTS/6% D (3% D), 7.5% HTS (7.5%), or 7.5% HTS/6% D (7.5% D). Mean arterial pressure (MAP) and tissue oxygen saturation (StO2) were recorded. Laboratory and thrombelastography (TEG) data were collected every 30 minutes. Animals were sacrificed 120 minutes after injury. Analysis of variance was used to compare groups. Significance was defined as p < 0.05. Baseline characteristics and laboratory values were similar in all groups. All groups achieved a similar degree of shock. Two NS and two 3% animals did not survive to 120 minutes. Fluids containing dextran produced a significantly greater increase in MAP (p < 0.02). Animals receiving 3% D maintained a higher MAP 90 minutes after fluid bolus. Also, 7.5% +/- D produced a significantly greater initial increase in StO2 (p < 0.05). This effect declined after fluid bolus while 3% D continued to improve tissue oxygenation. Significant differences developed between groups in TEG values, hematocrit, fibrinogen, urine sodium, serum sodium, serum chloride, and urine output. A single bolus of 3% D after uncontrolled hemorrhagic shock produces an adequate and sustained rise in MAP and StO2 and attenuates hypercoagulability. Resuscitation with 7.5% +/- D produces significantly increased urine output accompanied by a decline in MAP and StO2 over time. A single bolus of 7.5% D results in significant dilutional anemia and relative hypofibrinogenemia.

An In Vitro Model for Hemostasis Monitoring During Simulated Cardiopulmonary Bypass

The optimum model for hemostasis monitoring during cardiopulmonary bypass (CPB) is the evaluation of physiologic changes in the intact organism. This is often logistically difficult and expensive. The purpose of this study was to design an in vitro model of blood coagulation for use in simulated CPB. Human expired blood components within 4 days of outdating were reconstitituted as follows: 4 units of packed red blood cells, 4 units of platelets, and 3 units of fresh frozen plasma. The mixture was circulated in a simulated extracorporeal circuit. Blood samples were drawn every 30 minutes over a 2 hour period, recalcified, and analyzed for platelet count (PL T), fibrinogen concentration (FIB), prothrombin time (PT), activated partial thromboplastin time (aPTT), celite and kaolin activated clotting times (ACT), and thrombelastography (TEG). In the four different coagulation monitors utilized, there were no significant changes in celite or kaolin ACTs. PT increased from 15.8 ± 1.1 sec to 25.2 ± 7.8 sec and aPTT from 62.1 ± 15.9 sec to 78.9 ± 36.5 sec (p = NS). There were no changes in either PL T count or FIB concentration. Both celite and tissue factor activated TEG values trended towards hypocoagulability. In conclusion, the results show that the in vitro model is stable over 120 min of recirculation time within a simulated cardiopulmonary bypass circuit in regards to platelet count, hematocrit, total protein, PT, aPTT, and ACT. Further examination will be necessary to establish the effects of the model in regard to platelet function.

Hypercoagulability in patients with primary biliary cirrhosis and primary sclerosing cholangitis evaluated by thrombelastography

Background/Aims: Patients with primary biliary cirrhosis and primary sclerosing cholangitis survive variceal bleeding better than patients with alcoholic cirrhosis and have less bleeding at liver transplantation. Recently, patients with primary biliary cirrhosis have been found to have a higher incidence of thrombosis in the portal venous tree. We hypothesized that primary biliary cirrhosis and primary sclerosing cholangitis patients may be hypercoagulable. Methods: We used thrombelastography, which is a simple technique for evaluating whole blood clotting and fibrinolysis, to establish if hypercoagulability was present, defined by thrombelastography values greater than 2SD over controls: r<19 mm (this reflects plasma clotting factors), maximum amplitude (ma) > 60 mm, and alpha angle > 43° (these reflect platelets and fibrinogen levels). We evaluated 47 primary biliary cirrhosis and 21 primary sclerosing cholangitis patients, 40 with non-cholestatic cirrhosis and 40 healthy subjects as control groups with thrombelastography, full blood count, prothrombin time, partial thromboplastin time and, fibrinogen concentrations. In those with hypercoagulability we evaluated protein S, C, anti-thrombin III levels and activated protein C phenotype. Results: All three thrombelastography abnormalities present together defined hypercoagulability: these were found in 13 of 47 (28%) primary biliary cirrhosis and in nine of 21 (43%) primary sclerosing cholangitis patients independent of cirrhosis, and bilirubin concentration, but in only 2 of 40 (5%) patients with non-cholestatic cirrhosis and in none of the healthy controls ( p<0.03 and p<0.0002, respectively). There was no correlation between the fibrinogen concentration (which was normal in all patients) or platelet count and the thrombelastography parameters. Only six of the 22 hypercoagulable patients had lower than normal values of protein S, C or antithrombin III. Activated protein C phenotype was normal in all. Conclusions: This difference between biliary and parenchymal liver disease may have clinical implications, which need to be defined.