Potential value of transfusion protocols in cardiac surgery

Damage control resuscitation

The early recognition and management of hemorrhage shock are among the most difficult tasks challenging the clinician during primary assessment of the acutely bleeding patient. Often with little time, within a chaotic setting, and without sufficient clinical data, a decision must be reached to begin transfusion of blood components in massive amounts. The practice of massive transfusion has advanced considerably and is now a more complete and, arguably, more effective process. This new therapeutic paradigm, referred to as damage control resuscitation (DCR), differs considerably in many important respects from previous management strategies for catastrophic blood loss. We review several important elements of DCR including immediate correction of specific coagulopathies induced by hemorrhage and management of several extreme homeostatic imbalances that may appear in the aftermath of resuscitation. We also emphasize that the foremost objective in managing exsanguinating hemorrhage is always expedient and definitive control of the source of bleeding.

Prospective evaluation of blood coagulability and effect of treatment in patients with stroke using rotational thromboelastometry

BACKGROUND

Stroke is the second largest cause of death worldwide. Abnormalities in hemostasis play an important role in the pathophysiology of ischemic stroke (IS). These hemostatic defects can be detected using rotational thromboelastometry (ROTEM) as a global method of measuring coagulation. This study assessed the effects of IS on blood hypercoagulability using ROTEM method, before and subsequent to therapeutic interventions.

METHODS

In a prospective observational cohort study, whole blood coagulation using ROTEM, along with full blood count and standard coagulation tests, were compared between patients with IS and an age-matched control group of healthy volunteers. Further assessment took place at 2-4 hours and at 24 hours in the stroke group after therapy to assess the effects of therapeutic intervention.

RESULTS

Seventy-two patients with IS were age-matched to 71 healthy subjects. Clotting time (CT) INTEM (P = .01) and maximum clot firmness (MCF) INTEM (P = .02) were significantly different between stroke patients at baseline and healthy subjects, but this difference disappeared when controlled for by smoking status. There was no association between ROTEM parameters and time from stroke symptom onset or stroke severity as reflected in The National Institute of Health Stroke Scale score. Significant but small changes in the values of MCF-EXTEM, clot formation time (CFT) EXTEM, and alpha-EXTEM CT were observed after therapeutic intervention (thrombolysis or aspirin treatment).

CONCLUSIONS

ROTEM testing does not seem to detect a hypercoagulable state in patients with IS. Nonetheless, some ROTEM parameters had a small change after antiplatelet therapy or thrombolysis.

A 2014 Update on Coagulation Management for Cardiopulmonary Bypass

Coagulopathy after cardiac surgery with cardiopulmonary bypass is a serious complication that may result in massive bleeding requiring transfusion of significant amounts of blood products, plasma, and platelets. In addition to increased patient morbidity and mortality it is associated with longer hospital stay and increased resource utilization. The current review discusses aspects in cardiopulmonary bypass–induced coagulopathy with emphasis on point-of-care testing and individualized “goal-directed” therapy in patients who develop excessive bleeding after cardiac surgery.

Management of hemorrhage in cardiothoracic surgery

Bleeding is an important issue in cardiothoracic surgery, and about 20% of all blood products are transfused in this clinical setting worldwide. Transfusion practices, however, are highly variable among different hospitals and more than 25% of allogeneic blood transfusions have been considered inappropriate. Furthermore, both bleeding and allogeneic blood transfusion are associated with increased morbidity, mortality, and hospital costs. In the past decades, several attempts have been made to find a universal hemostatic agent to ensure hemostasis during and after cardiothoracic surgery. Most drugs studied in this context have either failed to reduce bleeding and transfusion requirements or were associated with severe adverse events, such as acute renal failure or thrombotic/thromboembolic events and, in some cases, increased mortality. Therefore, an individualized goal-directed hemostatic therapy ("theranostic" approach) seems to be more appropriate to stop bleeding in this complex clinical setting. The use of point-of-care (POC) transfusion and coagulation management algorithms guided by viscoelastic tests such as thromboelastometry/thromboelastography in combination with POC platelet function tests such as whole blood impedance aggregometry, and based on first-line therapy with fibrinogen and prothrombin complex concentrate have been associated with reduced allogeneic blood transfusion requirements, reduced incidence of thrombotic/thromboembolic and transfusion-related adverse events, and improved outcomes in cardiac surgery. This article reviews the current literature dealing with the management of hemorrhage in cardiothoracic surgery based on POC diagnostics and with specific coagulation factor concentrates and its impact on transfusion requirements and patients' outcomes.

TEG and ROTEM: technology and clinical applications

Initially described in 1948 by Hertert thromboelastography (TEG) provides a real-time assessment of viscoelastic clot strength in whole blood. Rotational thromboelastometry (ROTEM) evolved from TEG technology and both devices generate output by transducing changes in the viscoelastic strength of a small sample of clotting blood (300 µl) to which a constant rotational force is applied. These point of care devices allow visual assessment of blood coagulation from clot formation, through propagation, and stabilization, until clot dissolution. Computer analysis of the output allows sophisticated clot formation/dissolution kinetics and clot strength data to be generated. Activation of clot formation can be initiated with both intrinsic (kaolin, ellagic acid) and extrinsic (tissue factor) activators. In addition, the independent contributions of platelets and fibrinogen to final clot strength can be assessed using added platelet inhibitors (abciximab and cytochalasin D). Increasingly, ROTEM and TEG analysis is being incorporated in vertical algorithms to diagnose and treat bleeding in high-risk populations such as those undergoing cardiac surgery or suffering from blunt trauma. Some evidence suggests these algorithms might reduce transfusions, but further study is needed to assess patient outcomes.

Ökonomie und Gerinnungsmanagement

<b><i>Hintergrund: </i></b>Bei erworbenen oder chronisch bestehenden Störungen der Gerinnung ist in der perioperativen Phase eine gezielte Therapie von herausragender Bedeutung. Der kostenintensive Einsatz von Blut- und Gerinnungspräparaten und die Beeinflussung des Patientenoutcomes werden hinsichtlich des G-DRG(German Diagnosis Related Groups)-Systems und der Anwendung von Point-of-Care-Geräten bewertet. <b><i>Methode: </i></b>Anhand einer Literaturübersicht und eigener Daten wird der aktuelle Sachstand analysiert und diskutiert. <b><i>Ergebnisse: </i></b>Die perioperative Behandlung von Störungen der Gerinnung ist komplex. Neben der klassischen Labordiagnostik unterstützen und beschleunigen Point-of-Care-Geräte die Therapieentscheidungen. Die Anwendung eines Algorithmus-basierten Applikationsregimes von Blut- und Gerinnungspräparaten optimiert die Verbrauchsmengen und verbessert das Patientenoutcome. Demgegenüber können durch das G-DRG-System bedingte finanzielle Effekte aufgrund von kosten- und erlösseitigen Änderungen für das Krankenhaus negativ ausfallen. Fallpauschalen und Zusatzentgelte decken vor allem bei komplexen Behandlungsfällen wie der Lebertransplantation nicht die tatsächlichen Aufwendungen. Systemisch finanzielle Anreize zur Therapieentscheidung, die unabhängig von einer medizinischen Indikation sein können, sind vorherrschend. <b><i>Schlussfolgerungen: </i></b>Die Therapie von Gerinnungsstörungen stellt Ärzte, die Krankenhausverwaltungen und das G-DRG-System vor besondere Herausforderungen. Nicht selten besteht eine paradoxe Situation zwischen dem Streben nach einer bestmöglichen Patientenversorgung und einer adäquaten Leistungsvergütung des Krankenhauses. Finanzielle Anreize durch Pauschalen und Zusatzentgelte mit Mengenschwellen, die Therapieentscheidungen beeinflussen können, sind zukünftig zu eliminieren.