Prevention of Venous Thromboembolism - Covidien

Table 15—Thromboprophylaxis Trials in Critical Care Patients: Clinical Descriptions and Results (Section 8.0)*
Study/Year
Method of
Diagnosis
12 days, DVT was detected by routine venography in
28% of control subjects and 15% of LMWH recipients
(RRR, 45%; p � 0.045). Major bleeding rates
were 3% and 6%, respectively (p � 0.3). A large,
international trial 684 is currently underway to compare
the effectiveness and safety of LDUH and
LMWH in critical care patients.
When LMWH is administered as thromboprophylaxis
to ICU patients, the concomitant use of vasoconstrictor
drugs and possibly the presence of generalized
edema are associated with significantly
reduced anti-Xa levels presumably related to decreased
subcutaneous perfusion and drug absorption.
685–688 However, the influence of these observations
on the effectiveness of thromboprophylaxis
remains uncertain. Prophylactic doses of the LMWH
dalteparin do not appear to accumulate in ICU
patients with renal dysfunction. 111,689
It is essential for all ICUs to develop a formal
approach to thromboprophylaxis. 1 On admission to
the ICU, all patients should be assessed for risk of
VTE, and most should receive thromboprophylaxis.
The selection of thromboprophylaxis for these heterogeneous
patients involves a consideration of the
VTE and bleeding risks, both of which may vary from
day to day in the same ICU patient. When the
bleeding risk is high, mechanical thromboprophylaxis
should be started using GCS alone, or GCS
combined with IPC until the risk of bleeding decreases.
690 For ICU patients who are not at high risk
for bleeding, anticoagulant thromboprophylaxis is
recommended. For patients who are at moderate
risk for VTE, such as those with medical or general
surgical conditions, thromboprophylaxis with LMWH
or LDUH is recommended. For patients who are at
higher VTE risk, such as following major trauma or
orthopedic surgery, LMWH provides greater protection
than LDUH and is recommended. To prevent
interruption of protection, specific thromboprophylaxis
recommendations should be included in the patients’
orders when they are transferred from the ICU.
Recommendations: Critical Care
8.1. For patients admitted to a critical care unit, we
recommend routine assessment for VTE risk and
Intervention DVT†
Control Experimental Control Experimental
Cade 589 /1982 FUT for 4–10 d Placebo Heparin, 5,000 U SC bid NR/NR (29) NR/NR (13)
Fraisse et al 683 / Venography before Placebo Nadroparin, approximately
24/85 (28) 13/84 (15)
2000
d21
65 U/kg SC qd
*Randomized clinical trials in which routine screening with an objective diagnostic test for DVT was used in critical care unit patients. See Table
11 for expansion of abbreviations.
†Values given as No. of patients with DVT/total No. of patients (%).
routine thromboprophylaxis in most (Grade 1A).
8.2. For critical care patients who are at moderate
risk for VTE (eg, medically ill or postoperative
general surgery patients), we recommend using
LMWH or LDUH thromboprophylaxis
(Grade 1A).
8.3. For critical care patients who are at
higher risk (eg, following major trauma or
orthopedic surgery), we recommend LMWH
thromboprophylaxis (Grade 1A).
8.4. For critical care patients who are at high
risk for bleeding, we recommend the optimal
use of mechanical thromboprophylaxis with
GCS and/or IPC at least until the bleeding
risk decreases (Grade 1A). When the high
bleeding risk decreases, we recommend that
pharmacologic thromboprophylaxis be substituted
for or added to the mechanical thromboprophylaxis
(Grade 1C).
9.0 Long-Distance Travel
Prolonged air travel appears to be a risk factor for
VTE, although this risk is mild. 1,582,691–698 Depending
on differences in study design and populations, the
magnitude of the reported risk of VTE associated with
prolonged travel varies widely, ranging from no increased
risk to a fourfold-increased risk. 582,691–693,699–702
The incidence of travel-related VTE is influenced by
the type and duration of travel, and by individual risk
factors. 703–705 Although comparative data are limited,
thrombosis risk also appears to be increased for
travel by car, bus, or train. 699,702,706 An association
between air travel and VTE is strongest for flights
� 8 to 10 h in duration, 693,697,701,703–705 although a
case-control study 702 also found a twofold-increased
thrombosis risk for people who had traveled
� 4 h in the 8 weeks preceding the thromboembolic
event. Immobility during the flight also
appears to be an independent predictor of VTE, but
the risk is not influenced by whether the passenger
travels in economy class or business/first class. 707,708
Most individuals with travel-associated VTE have
one or more known risk factors for thrombosis, including
previous VTE, recent surgery or trauma, active
malignancy, pregnancy, estrogen use, advanced age,
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