Predictive value of rotational thromboelastometry during cardiopulmonary bypass for thrombocytopenia and hypofibrinogenemia after weaning of cardiopulmonary bypass

Platelet Contribution and Endothelial Activation and Stress Index-Potential Mortality Predictors in Traumatic Brain Injury

Coagulopathy and traumatic brain injury (TBI) are complexly intertwined. In isolated TBI, coagulopathy may contribute to hemorrhagic lesion development, progression, or recurrence, as it may lead to a particular pattern of coagulopathy called TBI-induced coagulopathy (TBI-IC). We performed a retrospective and descriptive evaluation of 63 patients admitted to the Emergency Clinical Hospital Bucharest with the diagnosis of moderate/severe brain injury. In addition to demographic data, all included patients had a complete paraclinical evaluation that included rotational thromboelastometric (ROTEM) blood-clot analysis. The platelet component (PLTEM) and the endotheliopathy activation and stress index score (EASIX) were calculated. These parameters were presented comparatively according to survival at 30 days and helped define the two study groups: survivors and non-survivors at 30 days. The contribution of platelets to clot strength is derived from maximum clot elasticity (MCE) and maximum clot firmness (MCF). MCE is defined as (MCF × 100)/(100 - MCF), and PLTEM is defined as EXTEM MCE-FIBTEM MCE. EASIX is a novel biomarker recently studied in TBI patients, calculated according to the following formula: lactate dehydrogenase (U/L) × creatinine (mg/dL)/platelets (109 cells/L). Regarding the demographic data, there were no significant differences between the survivors and non-survivors. All ROTEM parameters related to clot amplitude (A5, A10, A20, MCF in EXTEM and FIBTEM channels) were higher in the group of patients who survived. Also, PLTEM was decreased in the group of deceased patients (89.71 ± 22.86 vs. 132.3 ± 16.56 p < 0.0001). The cut-off point determined with the ROC curve is 114.10, with a sensitivity of 94.74% and a specificity of 93.18%, for the detection of the negative prognosis (death at 30 days). The EASIX score was significantly higher in the patients who survived the traumatic event, with a median difference value of 1.15 (p < 0.0001). The ROC analysis of this biomarker highlights a cut-off point of 2.12, with a sensitivity of 88.64% and a specificity of 94.74% (AUC = 0.95, p < 0.0001), for the prediction of mortality. The comparative analysis of the two studied markers was performed using the Cox proportional hazard ratio and highlighted the greater influence that PLTEM has on survival time (b value = -0.05, p < 0.0001) compared to EASIX (b value = 0.49, p = 0.0026). The present retrospective study indicates the potential of the TBI-IC reflecting parameters PLTEM and EASIX as markers of mortality prognosis. Larger prospective studies are needed to confirm their combined prognostic value and use in decision-making and reduction in the burden of disease by adequate allocation of resources in a personalized and timely manner.

Prediction of Mid-term Platelet Transfusion in Stable Trauma Patients Using Rotational Thromboelastometry

Background

Rotational thromboelastometry (ROTEM; TEM International GmbH, Munich, Germany) is a global coagulation test that guides evidence-based platelet transfusion in trauma patients. We evaluated ROTEM parameters for predicting mid-term (five days) platelet transfusion in trauma patients.

Methods

Maximum clot firmness and clot amplitudes after 5, 10, and 15 mins (A5, A10, and A15, respectively) of fibrin-specific ROTEM (FIBTEM) and extrinsically activated ROTEM (EXTEM) were retrospectively collected from 82 hospitalized, stable, non-bleeding trauma patients after successful initial resuscitation. Platelet-specific ROTEM (PLTEM) was calculated by subtracting FIBTEM from EXTEM. Platelet transfusions were reviewed for five days after ROTEM.

Results

The areas under the curve for FIBTEM, EXTEM, and PLTEM predicting platelet concentrate transfusion of >12 U at mid-term were 0.915-0.923, 0.878-0.896, and 0.551-0.735, respectively. FIBTEM and EXTEM parameters were comparable to those of fibrinogen, fibrin/fibrinogen degradation products, D-dimer, and antithrombin III. Strong correlations (r>0.7) were noted between platelet count and EXTEM (A5, A10, and A15) or PLTEM (A5), platelet function (per platelet count) and EXTEM (A10 and A15), and fibrinogen levels and all FIBTEM parameters.

Conclusions

FIBTEM and EXTEM can reliably predict mid-term platelet transfusion in trauma patients. FIBTEM, EXTEM, and PLTEM parameters correlate with conventional coagulation tests (platelets and fibrinogen).

Interest in the new thromboelastometry device, Clot Pro®, for predicting thrombocytopenia and hypofibrinogenemia during lung transplantation

INTRODUCTION

Lung transplantation is associated with high proportion of transfusion. Monitoring of coagulopathy using viscoelastic tests could aid in the perioperative management of bleeding. The aim of the study was to assess the predictive cut-off values for thrombocytopenia and hypofibrinogenemia using the new thromboelastography analyzer, ClotPro.

METHODS

We retrospectively enrolled 65 patients who underwent lung transplantation and were sampled for both viscoelastic assays and conventional coagulation assays simultaneously during the procedure. We characterized the correlation between the EX-test (extrinsic pathway) and platelet count as well as between the FIB-test (extrinsic pathway after platelet inhibition) and fibrinogen concentration. Then, we used ROC curve analysis to determine the optimal EX-test and FIB-test values for predicting thrombocytopenia and hypofibrinogenemia.

RESULTS

All the amplitude values of the EX-test (A5, A10, A20, MCF) showed correlation with platelets count (Spearman's rank correlation coefficient ranging from 0.75 to 0.77, all p < 0.0001). We also observed a strong correlation between the amplitude values of the FIB-test (A5, A10, A20 and MCF) and the fibrinogen concentration (Spearman's rank correlation coefficient ranging from 0.68 to 0.71, all p < 0.0001). The AUCs of the EX-test values for thrombocytopenia <100 G/L and <80 G/L ranged from 0.80 to 0.93. Similarly, the AUCs of the FIB-test values for hypofibrinogenemia <1.5 g/L and <2 g/L ranged from 0.74 to 0.83. These results indicate that only the five-minute parameter of thromboelastometry is sufficient for detecting thrombocytopenia and hypofibrinogenemia in patients undergoing lung transplantation. The proposed cut off values for the EX-test to predict thrombocytopenia <80 G/L showed high sensitivity (>86 %), high specificity (>89 %) and high negative predictive value (>95 %). FIB-test cut off values predictive of fibrinogen below 1.5 g/L showed sensitivity (>78 %), specificity (>55 %) and negative predictive value (>88 %).

CONCLUSIONS

Our study provided preliminary results that are useful for developing a ClotPro-based algorithm to guide transfusion in lung transplantation. Future interventional studies will be necessary to validate these cut-off values of ClotPro for guiding transfusion.

Rotational Thromboelastometry Values After On-Pump Cardiac Surgery - A Retrospective Cohort Study

BACKGROUND

Viscoelastic coagulation monitoring is recommended for coagulation management after cardiac surgery, but optimum target values are poorly defined.

AIMS

To determine "to-be-expected" values in rotational thromboelastometry (ROTEM) after heparin reversal, to correlate ROTEM parameters with fibrinogen levels and platelet count, and to estimate the effect of hemoglobin levels on these measurements.

METHODS

We retrospectively analyzed 571 consecutive adult patients undergoing cardiac surgery with cardiopulmonary bypass from 12/2018 to 08/2020. ROTEM and conventional laboratory measurements were performed 5 to 10 minutes after protamine administration.

RESULTS

Clotting times in EXTEM, INTEM, and FIBTEM were significantly prolonged (72.6%, 96.1%, and 31.8% above reference ranges, respectively). Clot firmness parameters in EXTEM and INTEM were relevantly reduced (7.9% to 14.4% and 9.1% to 32.3% below the reference ranges, respectively). There was an excellent linear correlation of FIBTEM amplitude after 10 min (A10) and of maximal clot firmness (MCF) with fibrinogen concentrations (r = .81 and .80). Areas under receiver operating characteristic (AUROC) for identifying hypofibrinogenemia <1.5 g/L were between .80 and .87. No effect of hematocrit was observed. We also found a linear correlation of EXTEM, INTEM, and EXTEM-FIBTEM at both A10 and MCF with platelet counts (.32 to .68). The AUROCs for identifying thrombocytopenia (<100,000/μL) were .79 to .84, and were greater for A10 than for MCF measurements (P=.074, .001, and <.001, respectively).

CONCLUSIONS

"To-be-expected" ROTEM values after CPB are different from the published reference ranges. ROTEM parameters might allow for reliable estimation of fibrinogen level and platelet count without being influenced by hematocrit.

Prediction of platelet counts with ROTEM-sigma in cardiac surgery

BACKGROUND

Excessive bleeding is common after cardiac surgery. According to transfusion algorithms based on ROTEM results, platelet transfusion is recommended when FIBTEM amplitude is normal and EXTEM amplitude is reduced. The aim of this study is to evaluate whether ROTEM parameters may predict accurately platelet counts in cardiac surgery patients and to determine which of these parameters is the most useful for predicting platelet counts.

METHODS

In this retrospective single center study data from 83 patients who underwent cardiac surgery were reviewed. We analysed the results of patients for whom ROTEM and conventional laboratory tests were performed simultaneously. The derived ROTEM parameter PLTEM was used to estimate platelet count, PLTEM is calculated by subtracting FIBTEM from EXTEM. Correlation between ROTEM variables and platelet counts were determined. Logistic regression analyses were performed to predict platelet counts.

RESULTS

ROTEM A5 values show a high linear correlation with MCF values. PLTEM has a strong linear correlation with platelet counts. According to our results for PLTEM A5 < 32 mm the probability of platelet count < 150 x 109/L is 100%, for PLTEM A5 < 27 mm the probability of platelet count < 100 x 109/L is nearly 80%, and for PLTEM A5 < 22 the probability of platelet count < 75 x 109/L is 70%.

CONCLUSIONS

This study demonstrates the reliability of considering early ROTEM results and the feasibility of using PLTEM A5 to predict platelet counts and so improve our ability to decide the need of platelet transfusion in cardiac surgery patients.

TEG6s Platelet Mapping assay for the estimation of plasma fibrinogen concentration during cardiovascular surgery: a single-center prospective observational study

PURPOSE

The Activator F (ActF) test on the TEG6s Platelet Mapping assay system is a means of quantifying blood viscoelasticity caused by fibrin network formation, triggered by reptilase and factor XIII, while platelets are inhibited. This unique methodology enables the measurement of blood viscoelasticity, even in highly heparinized blood. Here, we investigated whether fibrinogen concentration could be estimated using the ActF test in blood samples obtained during cardiopulmonary bypass (CPB) and after CPB in patients undergoing cardiovascular surgery.

METHODS

We performed a single-center prospective observational study at a university hospital. Forty patients aged ≥ 18 years who underwent elective cardiovascular surgery with CPB were enrolled. Blood samples were drawn after the induction of anesthesia, after declamping of the aorta during CPB, and after the reversal of heparinization using protamine (after CPB). Coagulation profiles were evaluated using the Platelet Mapping assay and standard laboratory tests.

RESULTS

There were strong correlations between the maximal amplitude of clot strength (MA) in the ActF test and fibrinogen concentration in samples drawn during CPB (R = 0.84, 95% confidence interval [CI] 0.72-0.91; P < 0.001) and after CPB (R = 0.83, 95% CI 0.70-0.91; P < 0.001). The areas under the receiver-operating characteristic curve for the ActF MA for fibrinogen concentrations < 150 mg/dL were 0.86 (95% CI 0.73-1.0) during CPB and 0.98 (95% CI 0.94-1.0) after CPB.

CONCLUSION

TEG6s Platelet Mapping ActF MA values strongly correlated with plasma fibrinogen concentration in highly heparinized blood during CPB and yielded highly accurate measurements of low fibrinogen concentrations.

Which factors have a great impact on coagulopathy and hemostatic impairment after cardiopulmonary bypass in cardiovascular surgery? An analysis based on rotational thromboelastometry

OBJECTIVES

This study aimed to investigate which factors have a great impact on coagulopathy after cardiopulmonary bypass (CPB) using rotational thromboelastometry (ROTEM).

METHODS

Ninety-eight patients undergoing cardiovascular surgery using CPB were enrolled. Data of amplitude 10 min after clotting time (A10) of ROTEM measured routinely before and after CPB were retrospectively collected. ROTEM has some assays by which we can evaluate the capacity of extrinsic coagulation (EXTEM), intrinsic coagulation (INTEM), fibrin polymerization (FIBTEM), and the effect of heparin (HEPTEM). The platelet component, defined as PLTEM, can be calculated by subtracting FIBTEM from EXTEM. Age, sex, total plasma volume, pre-CPB A10, lowest body temperature, in-out balance during CPB, intraoperative bleeding amount, and type of pumps were considered as possible factors. Univariate and multivariate analyses were performed for the rate of change of A10.

RESULTS

The change rate of each A10 had a significant negative correlation with bleeding amount (p < 0.01 for EXTEM, p < 0.01 for INTEM, p = 0.02 for FIBTEM, p < 0.01 for PLTEM). Female sex was a significant contributive predictor for the greater decline of EXTEM (p < 0.01) and INTEM (p < 0.01), positive balance for EXTEM (p < 0.01), FIBTEM (p = 0.01), and PLTEM (p < 0.01), long CPB time for INTEM (p = 0.01), centrifugal pump for FIBTEM (p < 0.01), and large pre-CPB A10 for PLTEM (p < 0.01).

CONCLUSION

In perioperative hemostatic management using ROTEM, attention should be given to the effects of these multiple factors.

The role of ROTEM variables based on clot elasticity and platelet component in predicting bleeding risk in thrombocytopenic critically ill neonates

BACKGROUND

Our aim was to investigate the role of thromboelastometry (ROTEM) parameters, including maximum clot elasticity (MCE) and platelet component (PLTEM MCE and PLTEM MCF), in early prediction of bleeding events in thrombocytopenic critically ill neonates.

MATERIAL AND METHODS

This single-center, prospective cohort study included 110 consecutive thrombocytopenic neonates with sepsis, suspected sepsis, or hypoxia. On the first day of disease onset, ROTEM EXTEM and FIBTEM assays were performed and the neonatal bleeding assessment tool was used for the evaluation of bleeding events.

RESULTS

Most EXTEM and FIBTEM ROTEM parameters significantly differed between neonates with (n = 77) and without bleeding events (n = 33). Neonates with bleeding events had significantly lower PLTEM MCE and PLTEM MCF values compared to those without bleeding events (P < .001). Platelet count was found to be strongly positively correlated with EXTEM A5 (Spearman's rho = 0.61, P < .001) and A10 (rho = 0.64, P < .001). EXTEM A10 demonstrated the best prognostic performance (AUC = 0.853) with an optimal cutoff value (≤37 mm) (sensitivity = 91%, specificity = 76%) for prediction of bleeding events in thrombocytopenic neonates.

CONCLUSIONS

EXTEM A5 and EXTEM A10 were found to be strong predictors of hemorrhage, compared to most ROTEM variables quantifying clot elasticity and platelet component in thrombocytopenic critically ill neonates.

Diagnostic accuracy of viscoelastic point-of-care identification of hypofibrinogenaemia in cardiac surgical patients: A systematic review

Hypofibrinogenaemia during cardiac surgery may increase blood loss and bleeding complications. Viscoelastic point-of-care tests provide more rapid diagnosis than laboratory measurement, allowing earlier treatment. However, their diagnostic test accuracy for hypofibrinogenaemia has never been reviewed systematically. We aimed to systematically review their diagnostic test accuracy for the identification of hypofibrinogenaemia during cardiac surgery. Two reviewers assessed relevant articles from seven electronic databases, extracted data from eligible articles and assessed quality. The primary outcomes were sensitivity, specificity and positive and negative predictive values. A total of 576 articles were screened and 81 full texts were assessed, most of which were clinical agreement or outcome studies. Only 10 diagnostic test accuracy studies were identified and only nine were eligible (ROTEM delta 7; TEG5000 1; TEG6S 1, n = 1820 patients) (ROTEM, TEM International GmbH, Munich, Germany; TEG, Haemonetics, Braintree, MA, USA). None had a low risk of bias. Four ROTEM studies with a fibrinogen threshold less than 1.5–1.6 g/l and FIBTEM threshold A10 less than 7.5–8 mm had point estimates for sensitivity of 0.61–0.88; specificity 0.54–0.94; positive predictive value 0.42–0.70; and negative predictive value 0.74–0.98 (i.e. false positive rate 30%–58%; false negative rate 2%–26%). Two ROTEM studies with higher thresholds for both fibrinogen (<2 g/l) and FIBTEM A10 (<9.5 mm) had similar false positive rates (25%–46%), as did the two TEG studies (15%–48%). This review demonstrates that there have been few diagnostic test accuracy studies of viscoelastic point-of-care identification of hypofibrinogenaemia in cardiac surgical patients. The studies performed so far report false positive rates of up to 58%, but low false negative rates. Further diagnostic test accuracy studies of viscoelastic point-of-care identification of hypofibrinogenaemia are required to guide their better use during cardiac surgery.

Hypothermic circulatory arrest induced coagulopathy: rotational thromboelastometry analysis

Objectives

Hypothermic circulatory arrest (HCA) has been considered to cause coagulopathy during cardiac surgery. However, coagulopathy associated with HCA has not been understood clearly in details. The objective of this study is to analyze the details of coagulopathy related to HCA in cardiac surgery by using rotational thromboelastometry (ROTEM).

Methods

We retrospectively analyzed 38 patients who underwent elective cardiac surgery (HCA group = 12, non-HCA group = 26) in our hospital. Blood samples were collected before and after cardiopulmonary bypass (CPB). Standard laboratory tests (SLTs) and ROTEM were performed. We performed four ROTEM assays (EXTEM, INTEM, HEPTEM and FIBTEM) and analyzed the following ROTEM parameters: clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF) and maximum clot elasticity (MCE). The amount of perioperative bleeding, intraoperative transfusion and perioperative data were compared between the HCA and non-HCA group.

Results

Operation time and hemostatic time were significantly longer in the HCA group, whereas CPB time had no difference between the groups. The amount of perioperative bleeding and intraoperative transfusion were much higher in the HCA group. SLTs showed no difference between the groups both after anesthesia induction and after protamine reversal. In ROTEM analysis, MCE contributed by platelet was reduced in the HCA group, whereas MCE contributed by fibrinogen had no difference.

Conclusion

Our study confirmed that the amount of perioperative bleeding and intraoperative transfusion were significantly higher in the HCA group. ROTEM analysis would indicate that clot firmness contributed by platelet component is reduced by HCA in cardiac surgery.

Acute normovolemic hemodilution for a patient with secondary polycythemia undergoing aortic valve replacement due to severe aortic stenosis - A case report

Background

A high hematocrit level in patients with erythrocytosis is linked with increased blood viscosity and increased risk of thromboembolism. Therefore, it is necessary to adequately lower the hematocrit level before performing a high-risk surgery.

Case

A 67-year-old male was scheduled for aortic valve replacement due to severe aortic stenosis. The preoperative hematocrit level of this patient was very high due to secondary polycythemia by hypoxia. We decided to perform acute normovolemic hemodilution after anesthetic induction to reduce the risk of thromboembolism in the patient. The patient was discharged after a successful surgery and a post-operative period without any side effects.

Conclusions

We estimate that patients with secondary polycythemia may benefit from acute normovolemic hemodilution to reduce their hematocrit levels while undergoing cardiac surgery using cardiopulmonary bypass. However, it is necessary to control the hematocrit level, since a significant decrease can cause side effects.

Novel scientific approaches and future research directions in understanding ITP

Diagnosis of immune thrombocytopenia (ITP) and prediction of response to therapy remain significant and constant challenges in hematology. In patients who present with ITP, the platelet count is frequently used as a surrogate marker for disease severity, and so often determines the need for therapy. Although there is a clear link between thrombocytopenia and hemostasis, a direct correlation between the extent of thrombocytopenia and bleeding symptoms, especially at lower platelet counts is lacking. Thus, bleeding in ITP is heterogeneous, unpredictable, and nearly always based on a multitude of risk factors, beyond the platelet count. The development of an evidence-based, validated risk stratification model for ITP treatment is a major goal in the ITP community and this review discusses new laboratory approaches to evaluate the various pathobiologies of ITP that may inform such a model.

Platelet Function Changes during Neonatal Cardiopulmonary Bypass Surgery: Mechanistic Basis and Lack of Correlation with Excessive Bleeding

Thrombocytopenia and platelet dysfunction induced by extracorporeal blood circulation are thought to contribute to postsurgical bleeding complications in neonates undergoing cardiac surgery with cardiopulmonary bypass (CPB). In this study, we examined how changes in platelet function relate to changes in platelet count and to excessive bleeding in neonatal CPB surgery. Platelet counts and platelet P-selectin exposure in response to agonist stimulation were measured at four times before, during, and after CPB surgery in neonates with normal versus excessive levels of postsurgical bleeding. Relative to baseline, platelet counts were reduced in patients while on CPB, as was platelet activation by the thromboxane A2 analog U46619, thrombin receptor activating peptide (TRAP), and collagen-related peptide (CRP). Platelet activation by adenosine diphosphate (ADP) was instead reduced after platelet transfusion. We provide evidence that thrombocytopenia is a likely contributor to CPB-associated defects in platelet responsiveness to U46619 and TRAP, CPB-induced collagen receptor downregulation likely contributes to defective platelet responsiveness to CRP, and platelet transfusion may contribute to defective platelet responses to ADP. Platelet transfusion restored to baseline levels platelet counts and responsiveness to all agonists except ADP but did not prevent excessive bleeding in all patients. We conclude that platelet count and function defects are characteristic of neonatal CPB surgery and that platelet transfusion corrects these defects. However, since CPB-associated coagulopathy is multifactorial, platelet transfusion alone is insufficient to treat bleeding events in all patients. Therefore, platelet transfusion must be combined with treatment of other factors that contribute to the coagulopathy to prevent excessive bleeding.

An introduction to point-of-care testing in extracorporeal circulation and LVADs

There is a delicate balance between bleeding and clotting in patients on circuits such as ventricular assist devices or extracorporeal membrane oxygenation. Traditional coagulation tests, prothrombin time, activated partial thromboplastin time, and anti-factor Xa levels, are used to monitor patients on these devices. However, turnaround times and inability to assess global hemostasis, including platelets and fibrinogen have contributed to a recognition that faster, accurate, and more informative coagulation tests are needed. Activated clotting time is used to monitor heparin in patients on circuits and has the advantages of being a near-patient point-of-care test. However, its utility is limited to heparin monitoring. Viscoelastic tests (thromboelastometry and thromboelastography) are global, whole-blood coagulation tests, and whole-blood platelet aggregometry evaluates platelet function. Ideally, these tests can ensure that patients are within the therapeutic range of their antithrombotic medications, identify patients at risk for hemorrhagic or thrombotic complications, and guide management of acute bleeding complications. This ideal is currently hampered by a lack of studies that delineate clear ranges that are clinically relevant. Future research is needed to better understand the optimal use of point-of-care coagulation testing in patients on extracorporeal circuits and ventricular assist devices.

An Audit of the Diagnostic Accuracy of Rotational Thromboelastometry for the Identification of Hypofibrinogenaemia and Thrombocytopenia during Cardiopulmonary Bypass

We audited the diagnostic accuracy of ROTEM® (TEM Innovations, GmbH, Munich, Germany) measurements of hypofibrinogenaemia (fibrinogen <1.5 g/l) and thrombocytopenia (platelet count <100 × 109/l) in 200 adult non-transplant patients during cardiopulmonary bypass (CPB). Blood samples were obtained for FIBTEM (assay for the fibrin part of the clot), PLTEM (calculated platelet-specific component), and laboratory measurements simultaneously. Our thresholds for FIBTEM and PLTEM were A10 (clot firmness 10 minutes after clotting time) ≤8 mm, and <35 mm respectively. We also calculated the accuracy of smaller thresholds and earlier indices. We found that FIBTEM A10 ≤8 mm had low sensitivity (0.62) for hypofibrinogenaemia. With the 13% hypofibrinogenaemia prevalence in our sample, the positive predictive value (PPV) was 0.47. In contrast, FIBTEM A10 ≤8 mm had higher specificity (0.90) (negative predictive value [NPV] 0.94). Of the other FIBTEM values analysed, only A5 ≤6 mm had similar or superior accuracy. The PLTEM results were less encouraging (sensitivity 0.81, specificity 0.62). With our prevalence of thrombocytopenia (also 13%), the PPV was only 0.24. However, the NPV was high (0.96). Of the other PLTEM values analysed, only A5 <25 mm had similar or superior accuracy. These findings indicate that during CPB FIBTEM A10 ≤8 mm and PLTEM A10 <35 mm have greater accuracy in identifying the absence of hypofibrinogenaemia and thrombocytopenia respectively than their presence. On the basis of these results we would be reassured by FIBTEM A10 values >8 mm and PLTEM A10 values ≥35 mm, but would continue to use laboratory measurements for confirmation. We would not use FIBTEM A10 ≤8 mm or PLTEM A10 <35 mm values alone to guide replacement therapy unless clinical conditions warranted an immediate decision before laboratory measurements were available.

Rotational Thromboelastometry Rapidly Predicts Thrombocytopenia and Hypofibrinogenemia During Neonatal Cardiopulmonary Bypass

BACKGROUND

Thrombocytopenia and hypofibrinogenemia during neonatal cardiopulmonary bypass (CPB) contribute to bleeding and morbidity. Rotational thromboelastometry (ROTEM) is a viscoelastic assay with a rapid turnaround time. Data validating ROTEM during neonatal cardiac surgery remain limited. This study examined perioperative hemostatic trends in neonates treated with standardized platelet and cryoprecipitate transfusion during CPB. We hypothesized that ROTEM would predict thrombocytopenia, hypofibrinogenemia, and the correction thereof.

METHODS

Forty-four neonates undergoing CPB were included in this prospective observational study. Blood samples were obtained at Baseline, On CPB, Post-CPB, and Postoperative. The ROTEM analysis included extrinsically activated (Extem) and fibrinogen-specific (Fibtem) assays. Platelet-specific thromboelastometry (Pltem) values were calculated. Platelet and cryoprecipitate transfusion was initiated prior to termination of CPB.

RESULTS

Platelet count and Extem amplitude decreased significantly On CPB ( P < .0001), increased significantly Post-CPB ( P < .0001), and Postoperative values were not significantly different from Baseline. Extem amplitude at 10 minutes (A10) > 46.5 mm (AUC = 0.941) and Pltem A10 > 37.5 mm [area under curve (AUC) = 0.960] predicted platelet count > 100 × 10³/μL, and they highly correlated with platelet count ( R = 0.89 and R = 0.90, respectively). Fibrinogen concentration and Fibtem amplitude decreased significantly On CPB ( P ≤ .0001) and normalized after cryoprecipitate transfusion. Fibtem A10 > 9.5 mm predicted fibrinogen >200 mg/dL (AUC = 0.817), but it correlated less well with fibrinogen concentration ( R = 0.65).

CONCLUSIONS

ROTEM analysis during neonatal cardiac surgery is sensitive and specific for thrombocytopenia and hypofibrinogenemia, identifying deficits within 10 minutes. Platelet and cryoprecipitate transfusion during neonatal CPB normalizes platelet count, fibrinogen level, and ROTEM amplitudes.

Microvascular reactivity measured by vascular occlusion test is an independent predictor for postoperative bleeding in patients undergoing cardiac surgery

The purpose of the study is to investigate the relationship between microvascular reactivity and postoperative bleeding in cardiac surgery. The authors retrospectively analyzed a prospectively collected registry of cardiac surgery patients. Data from 154 patients enrolled in the registry were analyzed. A linear mixed model was performed to evaluate the association between the amount of postoperative chest tube output (CTO, milliliter, repeatedly measured at 0-8, 8-24, and 24-48 h) and tissue oxygen saturation (StO₂₎ recovery slope (%/s) measured by vascular occlusion test (VOT) at skin closure. A logistic regression was carried out to see the relationship between StO₂ recovery slope and packed red blood cell (PRBC) transfusion during the 48-h postoperative period. In the multivariable adjusted model, the effect of StO₂ recovery slope on postoperative CTO (log-transformed) was statistically significant, and the degree of StO₂ recovery slope was inversely related to the amount of CTO (exp(estimate) = 0.935; exp(95% CI) 0.881-0.992; p = 0.027). StO₂ recovery slope was also inversely associated with postoperative PRBC transfusion possibility (OR = 0.795; 95% CI 0.633-0.998; p = 0.048). Microvascular reactivity measured by VOT is independently and inversely associated with postoperative bleeding in patients undergoing cardiac surgery.

Introduction of thromboelastometry-guided administration of fresh-frozen plasma is associated with decreased allogeneic blood transfusions and post-operative blood loss in cardiopulmonary-bypass surgery

BACKGROUND

Cardiac surgery is frequently associated with excessive blood loss requiring multiple blood transfusions which are, in turn, associated with increased morbidity and mortality. We evaluated the effectiveness of rotational thromboelastometry (ROTEM^®)-guided administration of fresh-frozen plasma (FFP) with regards to blood loss, transfusion requirements, and major post-operative complications.

MATERIALS AND METHODS

Coagulation management in 68 prospective patients undergoing cardiac surgery with cardiopulmonary bypass was based on a treatment algorithm guided by ROTEM^® measurements. The primary end-point was blood loss at 24 hours after surgery. Secondary end-points were: (i) need for allogeneic blood products after cardiopulmonary bypass and 24 hours post-operatively, and (ii) post-operative complications until discharge. The results were compared with those of a retrospective, control group of 69 patients who received empirical coagulation management before implementation of the ROTEM^®-guided algorithm.

RESULTS

Although patients with significantly lower haemoglobin levels received less packed red blood cells (PRBC) (840 vs 1,120 mL; p=0.031) and FFP (480 vs 720 mL; p=0.007) after introduction of the ROTEM^® algorithm, the intra-operative blood loss and post-operative haemoglobin levels were similar in the ROTEM^® and the retrospective control groups. In addition to significantly reduced blood loss and decreased requirements for PRBC (30.8 vs 62.3%; p<0.001) and FFP (25.0 vs 56.5%; p<0.001), the amounts of PRBC (315 vs 840 mL; p<0.001) and FFP (480 vs 840 mL; p=0.001) received during the first 24 hours after surgery were significantly reduced in the ROTEM^® group, as was the duration of post-operative hospitalisation.

DISCUSSION

Compared with empirical treatment, timely ROTEM^®-guided FFP administration during cardiac surgery can reduce not only overall blood product use and blood loss but also the duration of hospitalisation.

Thromboelastometry Versus Rotational Thromboelastography in Cardiac Surgery

Evidence exists on the morbiduty and mortality associated with both massive blood loss and transfusion in cardiac surgical patients. Monitoring of the vesicoelastic properties of blood using rotational thromboelastometry and thromboelsatography (TEG) has been a major step towards ameliorating the risks associated with these 2 evils by providing trageted goal-directed blood product resuscitation. Point of care ROTEM and TEG overcome many of the current limitatons of conventional laboratory coagulation testing. Despite the peaking interest and widespread use there is a lack of consensus whetehr the use of these devices to guide blood product resucistation is associated with a reduction in mortality. Also, both ROTEM and TEG suffer from some limitations resulting in a lack of agreement on the duperiority of one device versus the other. In this concise review we discuss the operational charecteristics of both devices and the pro-side of the use of ROTEM in cardiac surgery backed with the most recent evidence.