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Improving care of bleeding patients through research at Sunnybrook

Bleeding is a common surgical problem and a challenge that every surgeon has to face. Bleeding is particular challenge in trauma where it remains the most common cause of preventable death. Bleeding can be classified as mechanical (e.g. a lacerated liver) or coagulopathic – when hemostasis is defective and the patient becomes incapable of clotting effectively. Recent evidence suggests that shock is the main cause of early coagulopathy following trauma and not loss and consumption of clotting elements as previously believed. The best management of mechanical bleeding continues to be surgery while coagulopathy is essentially treated by replacing clotting elements with transfusion of blood product such as fresh plasma to replace clotting factors, platelets, and cryoprecipitate to replace fibrinogen.


Sandro Rizoli in the ROTEM Lab

The challenge in trauma is to recognize when the patient is coagulopathic. The clinical recognition of coagulopathy tends to be late, usually when there is diffuse nonstop oozing from surgical incisions, tube sites, mucosa, etc. Frequently the clinical diagnosis of coagulopathy occurs a few minutes before cardiac arrest. It is impossible to diagnose excessive clot breakdown (hyperfibrinolysis) clinically, which may be more common than recognized. A recent study published in Lancet (1) suggests that antifibrinolytic drugs reduce mortality in trauma.

Coagulopathy is better diagnosed by coagulation lab tests such as INR, aPTT, platelet count and fibrinogen levels. Unfortunately these tests may not be helpful in the context of exsanguinating hemorrhage because they take too long to be available (often more than 1 hour); may be normal even when the patient is markedly coagulopathic and have no correlation with bleeding. Remember that INR was created to evaluate coumadin therapy, not exsanguinating surgical bleeding. The combination of high mortality and lab tests of limited usefulness have led many Trauma Centers in North America to adopt Damage Control Resuscitation (DCR) for the management of massively bleeding patients. In DCR, all bleeding patients are presumed coagulopathic and receive large transfusions of red cells, fresh plasma and platelets from the start of resuscitation, while completely ignoring the lab. The evidence supporting DCR is weak and while it may have saved many lives, the chaotic and unguided transfusion of massive amounts of blood products may also have contributed to the poor outcome of others.

Thromboelastometry (TEM) is a coagulation assay used by some centers around the world for liver transplantation and cardiac surgery. TEM was recently proposed as a potentially ideal test for the diagnosis and management of coagulopathy in massive bleeding patients, particularly in trauma. The equipment consists of a pin (channel) that is immersed into a cup, containing a few drops of the patient’s blood. As the liquid blood within the cup turns into a clot and subsequently undergoes lysis, the viscoelastic resistance over the pin changes and these changes are measured by a computer that generates a graphic representation. The graph generated and its measurements are very simple to interpret. TEM evaluates the whole coagulation process, from initiation to propagation to lysis. It measures how quickly the clot is formed (that is clotting factor dependent); the maximum strength of the clot (that depends on platelets and fibrinogen) and also measures clot breakdown or fibrinolysis. Another reason TEM is considered superior to standard coagulation lab tests is the fact it can guide transfusion (for example: patients with excessive fibrinolysis need antifibrinolytic drugs and not plasma transfusion). There are two different TEM devices commercially available, but the European model (ROTEM or rotational thromboelastometry) is more sophisticated and performs 4 different tests including specific ones for platelets and fibrinogen. A few places in the world are starting to explore the usefulness of ROTEM in trauma. In North America Sunnybrook is the first one.


Rotem Trauma Room

The Sunnybrook Trauma Program led by Homer Tien is the largest in Canada and approximately 4% of our patients are admitted with massive bleeding. Some of these patients require so much blood during resuscitation that they put at risk the blood inventory for the city of Toronto. Massive bleeding is not only an area of major clinical interest at Sunnybrook but also its main focus of research. The motivation to acquire a ROTEM was the unique opportunity it offered to advance both trauma research and clinical care to a cutting-edge position. First we applied for a Special Authorization from Health Canada to use ROTEM clinically. Then the equipment was loaned by the manufacturer and installed with funds from the De Souza Research Chair. It has been proposed that the equipment be installed in the Trauma Resuscitation Room and used for point of care testing. Thanks to Elena Brnjac and the Sunnybrook Department of Clinical Pathology, we were able to place the equipment in the Hospital Lab where it will be done by trained technologists and according to the highest lab standards. In order to have the results immediately available for clinical decision-making, a large screen has been placed in the Trauma Room that is directly linked to the ROTEM in the lab. The screen will display the results in real time and can be used to diagnose coagulopathy and help in deciding which blood product to transfuse and how much. Another innovation is linking ROTEM to the Operating Rooms with similar real time display of the results. In the OR, the test will help surgeons and anesthetists resuscitate patients undergoing emergent surgery. We expect to be doing ROTEM tests in all trauma patients admitted to Sunnybrook starting July 28th.

The ROTEM project is a fascinating advance for trauma research at Sunnybrook. Over the last years, trauma surgeons Sandro Rizoli, Homer Tien, Lorraine Tremblay and transfusion specialists Jeannie Callum, Bartolomeu Nascimento, Marciano Reis have worked together in a growing number of clinical trials focused on traumatic coagulopathy and blood transfusion in trauma. Like before, the current ROTEM project will have a direct impact on patient care. The group is also conducting the first randomized controlled trial on DCR with funding from the Canadian Forces Health Services, and recently created the Sunnybrook Code Omega, a protocol for the management of massive bleeding. Their collaboration also led to the Massive Transfusion Consensus Conference, an international meeting held at the Sheraton Hotel in Toronto June 9-11, 2011. This Conference attracted world renowned surgeons, anesthetists, hematologists and transfusion specialists. It resulted in consensus guidelines on massive transfusion, which will be published in Critical Care before the end of 2011.

Even today, the mortality of the coagulopathic bleeding trauma patients remains unacceptably high around 40%. Our expectation in being among the first to explore the role of ROTEM in trauma, is to be able to advance the research on the physiopathology of coagulopathy in trauma, improve our clinical ability to diagnose and treat coagulopathy, make better and more rational use of blood transfusions and reduce the enormous mortality and suffering of these patients.

Sandro Rizoli
De Souza Trauma Research Chair
CIHR/NovoNordisk New Investigator Chief Region XII
Committee on Trauma, American College of Surgeons

1. CRASH-2 collaborators, Roberts I, Shakur H, Afolabi A, Brohi K, Coats T, Dewan Y, Gando S, Guyatt G, Hunt BJ, Morales C, Perel P, Prieto-Merino D, Woolley T. - The importance of early treatment with tranexamic acid in bleeding trauma patients: an exploratory analysis of the CRASH-2 randomised controlled trial. Lancet. 2011 Mar 26; 377(9771):1096-101, 1101.e1-2

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