Abstract
Abstract: Managing hemorrhagic shock is complex and difficult, and hemorrhage remains the leading cause of preventable deaths among trauma patients. There is an on-going debate on the best resusciative strategy. Many intensive care units practice massive transfusion protocols with resuscitation fluids composed of Packed Red Blood Cells (PRBC), Fresh Frozen Plasma and platelets in equal ratios, thus resembling whole blood. Some studies reported a great survival benefit from this relative high proportion of FFP, but most of this benefit has later been shown to be due to a survival bias. Trauma-induced coagulopathy (TIC) is present in 10-34 percent of trauma-patients at admission to the intensive care unit. A feared complication to massive hemorrhage includes the so-called «viscous cycle» of hypothermia, acidosis and coagulopathy, which is associated with increased morbidity and mortality. To understand the pathophysiology behind this, knowledge of hemostasis is needed. Endothelium, platelets and coagulation proteins are the constituents that together provide the hemostatic pathways. Each system constituent interacts with and influences all other constituents. While the coagulation proteins previously have been the only accessible constituent, newer techniques are now available. Viscoelastic hemostatic assays (VHAs), including thromboelastography and thromboelastometry, allows «point of care» evaluation of the coagulation in whole blood, and hence gives more information about clotting in vivo. It remains to tell whether the use of VHAs as guide for massive transfusion protocols will improve outcomes. Evolving evidence appears to link damage to the endothelium as a key factor to TIC. The endothelium, estimated to represent an area of 4000-7000 m2 and some 1013 cells, and its tremendous heterogeneity, is by far the constituent of the hemostatic systems most difficult to study. New insight is emerging, however. The availability of «point of care» testing is getting more common in intensive care units. Will a better understanding lead to altered transfusion protocols? And will «point of care» monitoring lead to improved outcomes through earlier diagnosis and more targeted therapy? Based on non-systematical search of relevant literature, the present study addresses these issues.