الفهرس | Only 14 pages are availabe for public view |
Abstract The pathogenesis of thrombus formationmay be explained according to Virchow’s triad (blood vesseldamage, alteration in blood constituents and venous stasis). Trauma victims may fulfil all three requisites of this classic triad. Hence, deep venous thrombosis is a major cause for concern amongst multipletrauma victims owing to the potentially fatal consequences associated with pulmonary embolism. Venous thromboembolism frequently complicates the management of patients with severe medical and surgical illnesses. Because the diagnosis of venous thrombo-embolism is especially challenging in critically ill patients, the focus of intensivists should be on characterization of risk factors and the appropriate choice of VTE prophylaxis. The VTE risks in critically ill patients vary considerably, although most intensive care unit (ICU) patients have multiple risk factors for VTE and an overall moderate-to-high risk. Some of the patient risk factors that predate the ICU admission include recent surgery, trauma, sepsis, malignancy, immobilization, increased age, heart or 81 respiratory failure, and previous VTE. Other thrombotic risk factors that may be acquired during the ICU stay include immobilization, pharmacologic paralysis, central venous lines, surgical procedures, sepsis, mechanical ventilation, vasopressor use, and hemodialysis. Neither D-dimer levels nor tests of hypercoagulability (activated protein C resistance ratio, Prothrombin 20210A gene mutation, levels of protein C, protein S, or antithrombin, anticardiolipin antibody titer, and lupus anticoagulant) had any predictive value for DVT in critically ill patients. Low density unfractionated heparin (LDUH) or low molecular weight heparin (LMWH) is the preferred choice for VTE prophylaxis in ICU patients. Mechanical methods of prophylaxis should be reserved for patients with a high risk for bleeding. The effectiveness of mechanical methods and of combined strategies of prevention and the clinically important outcomes of therapy need to be explored further in critically ill patients. LDH and LMWH were significantly more effective than no prophylaxis in ICU patients. Unfortunately, these two anticoagulants have never been directly compared in critical care patients. A large, multinational randomized 82 trial is now underway to compare the effectiveness and safety of LDH and LMWH in this setting. The selection of an appropriate method of thromboprophylaxis should be assessed on admission to the critical care unit. This decision involves a consideration of the thromboembolic and bleeding risks, both of which may vary in the same patient, from day to day. For ICU patients at high risk for bleeding, mechanical prophylaxis with intermittent pneumanetic cough (IPC)and/or graduated compression stockings (GCS) is recommended until the bleeding risk decreases, although this has never been studied in a general ICU setting. For ICU patients not at high risk for bleeding with a moderate thrombosis risk (e.g., medically ill or general surgical problems) either LMWH or LDH is recommended. For patients at higher risk (e.g., following major trauma or orthopedic procedures), LMWH provides greater protection than LDH and is recommended. To prevent interruption of thromboprophylaxis, specific prophylaxis recommendations should be included in the patients’ orders when they are transferred from the ICU. Venous thromboembolism is a common, potentially lethal complication of hospitalization for major trauma, spinal cord injury (SCI) and other critical illnesses. Despite the availability of evidence-based prophylaxis recommendations for these groups, the use of this important patient safety intervention is frequently suboptimal. |