Point of Care Testing and Cardiac Surgery 2014

Thromboelastometry as guidance for blood management in patients undergoing cardiac surgery

OBJECTIVE

Thromboelastometry is a viscoelastometric method for haemostasis testing in a whole blood sample. The aim of this study was to assess the results of using thromboelastometry as guidance for blood management in cardiac surgery, postoperative adverse events and ICU stay.

MATERIAL AND METHOD

Analytical and comparative non-randomised quasi-experimental prospective study with a retrospective control group. The inclusion criteria for the 80 patients were: patients undergoing cardiac surgery who had had prior cardiac surgery, endocarditis surgery or aortic arch surgery. Thirty-one patients were treated following routine transfusion practice during surgery (group A). The other 49 patients were treated with thromboelastometrically guided transfusion algorithms (group B). The main objective was blood products transfused, and postoperative adverse events and ICU stay were the secondary objectives.

RESULTS

Statistical analysis showed lower transfusion rates of fresh-frozen plasma in group B compared to group A (P<.001), as well as red blood cell transfusion during surgery with an average transfusion rate of 3.9 units in group A in comparison to 2.67 units in group B (P=.125). Moreover, fibrinogen infusion was increased in group B compared to group A (P=.019). In addition, a lower rate of respiratory adverse events was found in group B (P=.019). There was a significant decrease in ICU stays over 7 days in group B compared to group A (P=.031).

CONCLUSIONS

Using thromboelastometry guidance for blood management led to a meaningful reduction of fresh frozen plasma transfusion during surgery. This probably resulted in a reduction in respiratory adverse events after surgery and length of ICU stay in our patients.

Correlation of pre-operative plasma protein concentrations in cardiac surgery patients with bleeding outcomes using a targeted quantitative proteomics approach

PURPOSE

Despite recent advancements in the use of thrombelastography (TEG) in the surgical setting, adequate technology to accurately predict bleeding phenotypes for patients undergoing cardiopulmonary bypass on the basis of non-mechanical parameters is lacking. While basic science and translational studies have provided key mechanistic insights about the protein components of coagulation cascades and regulatory mediators of hemostasis and fibrinolysis, targeted protein assays are still missing and the association of protein profiles to bleeding phenotypes and TEG readouts have yet to be discovered.

OBJECTIVE

To identify protein biomarkers of bleeding phenotypes of cardiopulmonary bypass patients in pre-operative plasma.

EXPERIMENTAL DESIGN

We applied a targeted proteomics approach to quantify 123 plasma proteins from 23 patients undergoing cardiopulmonary bypass (CPB) and sternotomy. We then correlated these measurements to bleeding outcomes and TEG parameters, associated with speed of clot formation and strength.

RESULTS

In this pilot study, we demonstrate the feasibility of protein quantitation as a viable strategy to predict low versus high bleeding phenotypes (loss of < or > than 20% of estimated blood volume, calculated as 70 mL/kg for BMI<29.9, 60 mL/kg for BMI = 30-39.9, and 50 mL/kg for BMI>40. Statistical elaborations highlighted a core set of proteins showing significant correlations to either total blood loss or TEG R/MA parameters.

CONCLUSION AND CLINICAL RELEVANCE

Though prospective verification and validation in larger cohorts will be necessary, this report suggests a potential for targeted quantitative proteomics of pre-operative plasma protein concentrations in the prediction of estimated blood loss following CPB.

Higher fibrinogen concentrations for reduction of transfusion requirements during major paediatric surgery: A prospective randomised controlled trial

BACKGROUND

Hypofibrinogenaemia is one of the main reasons for development of perioperative coagulopathy during major paediatric surgery. The aim of this study was to assess whether prophylactic maintenance of higher fibrinogen concentrations through administration of fibrinogen concentrate would decrease the volume of transfused red blood cell (RBCs).

METHODS

In this prospective, randomised, clinical trial, patients aged 6 months to 17 yr undergoing craniosynostosis and scoliosis surgery received fibrinogen concentrate (30 mg kg(-1)) at two predefined intraoperative fibrinogen concentrations [ROTEM(®) FIBTEM maximum clot firmness (MCF) of <8 mm (conventional) or <13 mm (early substitution)]. Total volume of transfused RBCs was recorded over 24 h after start of surgery.

RESULTS

Thirty children who underwent craniosynostosis surgery and 19 children who underwent scoliosis surgery were treated per protocol. During craniosynostosis surgery, children in the early substitution group received significantly less RBCs (median, 28 ml kg(-1); IQR, 21 to 50 ml kg(-1)) compared with the conventional fibrinogen trigger of <8 mm (median, 56 ml kg(-1); IQR, 28 to 62 ml kg(-1)) (P=0.03). Calculated blood loss as per cent of estimated total blood volume decreased from a median of 160% (IQR, 110-190%) to a median of 90% (IQR, 78-110%) (P=0.017). No significant changes were observed in the scoliosis surgery population. No bleeding events requiring surgical intervention, postoperative transfusions of RBCs, or treatment-related adverse events were observed.

CONCLUSIONS

Intraoperative administration of fibrinogen concentrate using a FIBTEM MCF trigger level of <13 mm can be successfully used to significantly decrease bleeding, and transfusion requirements in the setting of craniosynostosis surgery, but not scoliosis.

CLINICAL TRIAL REGISTRY NUMBER

ClinicalTrials.gov NCT01487837.