الفهرس 
Estimated incidence of venous thromboembolism by age, race, and genderOnly 14 pages are availabe for public view
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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
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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
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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.