- See:
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Coag Pathway
-
Pulmonary Embolus
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DVT in Hip Frx and Surgery:
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DVT Following THR:
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DVT Following TKR:
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DVT / PE arising from Trauma and Fractures
- Prophylatic Measures
-
specific agents for risk reduction:
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aspirin:
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thrombolytic therapy:
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SQ heparin
-
low molecular wt heparins
- may be more effective in total hip arthroplasty as compared to total knee arthroplasty;
- typically LMWH are administered 12-24 hours following surgery and is continued for 14 days;
- recombinant hirudin desirudin:
- may offer up to 86% risk reduction of DVT;
- direct inhibitor of thrombin;
-
warfarin
- danaparoid:
- low molecular wt glycosaminoglycan with potent anti factor Xa activity;
-
fondaparinux
-
bleeding complications:
- difficulty in assessing the risk of bleeding complications amongst various agents depends mainly on dose of meds used and amount of monitoring used;
- ie, to achieve the desired anticoagulation effect (and DVT prophylaxsis), how much bleeding are we willing to accept?
- published bleeding complications note 5% bleeding from LMWH, 3% bleeding from coumadin, and 2.5% from SQ heparin;
- in contrast, the bleeding complications from ASA is approximately 0.4%;
-
mechanical methods for risk reduction:
- note that there is a large venous plexus in the foot which is compressed when the foot is flattened with wt bearing;
- wt bearing compresses about 30 ml out of the foot and flushes it into the deep venous system;
- foot pump systems attempt to reproduce this effect;
- TED hose (compression stockings) are recommended when using mechanical devices inorder to help control venous capacitance;
-
compression stockings:
- note that mechanical compression devices that wrap around the leg cannot be used in total knee patients;
- in the study by Warwick et al 1998, DVT was noted in 18% of foot pump patients vs 13% of enoxaparin patients (no sig difference);
- patients in the enoxaparin group had significantly more bruising, thigh swelling, and wound oozing;
- the authors used venography to evaluate DVT formation;
- the authors concluded that foot pump devices had comprable efficacy to low molecular wt heparin;
- references:
- Comparison of use of a foot pump w/ use of LMWH for prevention of DVT after THR. Warwick et al. JBJS. Vol 80-A. Aug. 1998. p 1158.
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foot movement:
- sustained movement of the foot (30 cycles for one minute) will produce a sustained increase in the
venous outflow (22 % greater than baseline) which gradually returns to the base line after 30 min;
- references:
- The effect of active movement of the foot on venous blood flow after after total hip replacement. MA McNally JBJS Vol 79-A. No 8. Aug 1997. p 1198.
-
epidural anesthesia:
- epidural anesthesia has clearly been shown to reduce prevalence of DVT;
- potential problem is that blood thinning agents cannot be used as long as the epidural catheter is in place (due to the risk of
epidural hematoma and resulting neurologic deficit);
- reference:
The Prevalence of Deep Venous Thrombosis after Total Hip Arthroplasty with Hypotensive Epidural Anesthesia.
-
references
References
Comparison of Enoxaparin and Warfarin for the Prevention of Venous Thromboembolic Disease After Total Hip Arthroplasty. Evaluation During Hospitalization and Three Months After Discharge
CW Colwell et al JBJS July 1999, Vol 81-A, No 7.
Finding the right fit: Effective thrombosis risk stratification in orthopeadic patients.
JI Arcelus MD PhD et al. Orthopedics. Jun 2000. Vol 23. No 6. p 633.
