الفهرس 
Coagulation biomarkers in critically ill patientsOnly 14 pages are availabe for public view
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Abstract
Coagulation abnormalities occur frequently in critically ill patients and may have a major impact on the outcome. An adequate explanation for the cause of the coagulation abnormality is important, since many underlying disorders may require specific treatment. Treatment of coagulation abnormalities in critically ill patients should be directed at the underlying condition, but supportive therapy may be required. Deficiencies in platelets and coagulation factors in bleeding patients or patients at risk for bleeding can be achieved by transfusion of platelet concentrate or plasma products, respectively. In addition, prohemostatic treatment may be beneficial in case of severe bleeding, whereas restoring physiological anticoagulant pathways may be helpful in patients with sepsis and DIC.
Critical illness is frequently complicated by preexisting cardiovascular disease and heart failure. Similarly, the development of ischemia and myocardial suppression from common ICU conditions complicates a patient’s course. Therefore, well established cardiac biomarkers might be useful in the ICU setting for the diagnosis and risk assessment of cardiac disease complicating critical illness. Although elevated troponin and natriuretic peptides likely signal a poor prognosis in shock ( including septic shock), whether they should be routinely incorporated into clinical practice is currently unclear. Although the natriuretic peptides may be useful in differentiating acute lung injury from heart failure, these markers do not clearly track with filling pressures or volume status.
In acute pulmonary embolism, the patients who will benefit the most from a biomarker-guided strategy are those who present without shock but may have evidence of early right ventricular ischemia (potentially detected by troponin or H-FABP) or right ventricular pressure loading (with release of natriuretic peptides) .
Cardiac biomarkers may ultimately play an important role in critical care, with several caveats. First, specific assays have limitations, assay cut-offs have not been clearly established, and measurements during dynamic critical illness may be problematic. Second, biomarker interpretation may vary depending on individual patient characteristics and ICU diagnosis. Last, any marker measured in isolation is unlikely to surpass careful bedside assessment.
Recent improvements in our understanding of AKI have enabled us to better recognize and identify early changes within the spectrum of kidney injury. AKI is prevalent among ICU patients and carries significant clinical and financial costs. The previous lack of consensus about the classification of ARF and limited diagnostic tools to identify early renal dysfunction impeded research and development of early prevention and treatment strategies for AKI. The longstanding need for earlier and more reliable detection of AKI has led to the discovery of promising biomarkers for AKI, such as NGAL, IL-18, cystatin C, and KIM-1, which have the potential to be analogous to troponins in the management of cardiac ischemia. In the future, these novel biomarkers will likely prove invaluable for the prevention and clinical management of AKI .
Study of biomarkers has led to improved understanding of the pathogenesis of ALI. To date, markers of inflammation (IL-6, IL-8, and sTNFr-I & II), epithelial and endothelial injury (RAGE, SP-D, ICAM-1 and VWf-Ag), and altered coagulation (protein C and PAI-1) correlate with mortality in large multicenter clinical trials of ALI. However, our improved understanding of the pathways involved in the ALI has not yet resulted in pharmacotherapy with proven survival benefit. The creation of large tissue banks of wellphenotyped patients with ALI and advances in the study of genomics and proteomics should provide continued refinement of our understanding of ALI.
Biomarkers of sepsis are clinically useful only if they fulfill certain requirements. These must be closely related to therapeutic consequences. Among the various biomarkers of sepsis available, most of them fulfill only a fraction of these requirements, such as improved diagnosis of bacterial infection or a better assessement of the severity of the host response to infection. Their biochemical properties , stability, half-life of induction and elimination, range of available concentrations, their correlation with severity of the disease, and response to therapy and prognosis are different for each marker. Presently, procalcitonin fulfills most of these criteria. Diagnosis of sepsis and monitoring of patients at risk of sepsis, severe sepsis, or septic shock can be improved by this parameter, although presently there are no studies available evaluating the effect of procalcitonin measurement on the outcome. A number of studies and clinical data have clearly shown an improvement in the diagnosis of sepsis, when modern biomarkers of sepsis are used.