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dvt_proph

DVT prophylaxis

introduction

  • all hospital patients should have VTE risk assessment performed
  • high risk patients generally require:
    • pharmacologic prophylaxis if not C/I,
    • PLUS one mechanical prophylaxis if not C/I
  • moderate risk patients generally require:
    • pharmacologic prophylaxis if not C/I
    • OR one mechanical prophylaxis if not C/I
    • PLUS early mobilisation and patient education
  • low risk patients generally require:
    • no need for pharmacologic or mechanical prophylaxis
    • BUT early mobilisation and patient education should be given
  • pregnant patients
    • some patients may require FULL therapeutic anticoagulation
      • requirement for anticoagulation prior to pregnancy
      • PH VTE with high risk thrombophilia
      • recurrent unprovoked VTE
      • VTE in current pregnancy
    • other patients may require prophylactic enoxaparin 40mg once daily s/c
      • for whole of pregnancy from 1st TM:
        • PH unprovoked VTE
        • recurrent provoked VTE
        • active autoimmune or inflammatory disorder
        • Medical co-morbidity: (e.g. cancer, nephrotic syndrome, heart failure, sickle cell, type I diabetes with nephropathy)
        • high VTE risk score
      • only while admitted to hospital:
        • general antenatal patients
        • ovarian hyperstimulation syndrome in 1st TM
        • any surgery
        • severe hyperemesis or dehydration
      • from 28wks gestation:
        • moderate VTE risk score

Pharmacologic prophylaxis

  • anticoagulant:
      • usual dose: 40 mg subcutaneous daily
      • if Creatinine Clearance < 30mL/min: 20 mg subcutaneous daily or use heparin
    • or, heparin:
      • 5,000 units subcutaneous 8-12 hourly
    • or, oral agents may be appropriate for some patients
  • duration of Rx:
    • medical patients:
      • continue until acute medical condition is stable, patient is mobile or until hospital discharge
    • post-op patients:
      • THR or hip fracture surgery: 28-35 days
      • TKR surgery: 14 days
      • lower leg immobilisation: until fully mobile
      • major general surgery: up to 1 week or until fully mobile

C/I to pharmacologic prophylaxis

absolute C/I

  • active haemorrhage
  • severe trauma to head or spinal cord with haemorrhage within past 4 weeks
  • coagulopathy
  • thrombocytopaenia < 50 x x 10^9/L
  • end stage liver disease with INR > 1.5
  • therapeutic pharmacologic anticoagulation already in place

relative C/I

  • intracranial haemorrhage within last 1 yr
  • craniotomy in last 2 weeks
  • intraocular surgery in last 2 weeks
  • GIT or genitourinary tract haemorrhage in past month
  • active intracranial lesions or neoplasms
  • hypertensive emergency
  • pos-op bleeding concerns
  • use of anti-platelets eg. clopidogrel
  • inherited bleeding disorder
  • high falls risk

special considerations

  • heparin sensitivity of PH HIT
  • insertion/removal of epidural catheter or spinal needle (lumbar puncture) (current or planned)
    • should be carried out ≥ 4 hours BEFORE a prophylactic dose of LMWH AND ≥ 10 hours after a previously administered dose.
  • creatinine clearance <30mL/min
  • acute stroke - seek advice
  • neurosurgery - seek advice
  • weight < 50kg - adjust dose
  • weight > 100kg - adjust dose

Mechanical methods of DVT prophylaxis in adults

  • Mechanical methods of prophylaxis increase venous outflow and /or reduce stasis within the leg veins.(ACCP Conference on Antithrombotic and Thrombolytic Therapy 2004).
  • Whilst they have been shown to reduce the risk of DVT in a number of patient groups, these methods have been studied far less extensively than anticoagulant-based options.
  • Mechanical methods of prophylaxis are generally less efficacious than anticoagulant based options and are primarily recommended for patients with high bleeding risks or as an adjunct to anticoagulant-based prophylaxis for patients assessed as being at moderate to very high risk of VTE.
  • The effectiveness of mechanical methods of prophylaxis is dependent upon appropriate fit and use.

C/I to mechanical prophylaxis

  • skin ulceration
  • severe dermatitis
  • lower leg trauma
  • severe lower leg deformity
  • recent low limb DVT (although anti-embolic stockings can be used)
  • massive leg oedema or pulmonary oedema due to congestive cardiac failure
  • morbid obesity where correct fitting is not possible
  • peripheral neuropathy although intermittent pneumatic compression can be used
  • recent skin graft
  • stroke patients - avoid anti-embolic stockings

Intermittent pneumatic compression devices

  • Augment the inherent ability of the calf muscle to function as a pump in forcing blood from the venous sinuses and stimulating endogenous fibrinolytic activity (Rice 2001).
  • IPC devices are available in single-chamber or multi-chamber types and provide intermittent or sequential pressure at predetermined time intervals.
  • Note: Assessment of appropriate application, device function and skin integrity under the sleeve must be undertaken at least once per shift.

Graduated compression stockings (GCS)

  • Studies have generally involved full-length stockings although it is anticipated that below knee stockings should also provide a degree of protection against DVT. As there few comparative studies, no recommendation can be made with regard to the length of stockings.
  • The decision on the length of stockings to be worn i.e. full-length vs. knee-high, is to be made by the Senior treating clinician or as per the treating Unit’s protocol
  • Regardless of the length of GCS the following recommendations are made:
  1. Ideal characteristics of GCS for DVT prophylaxis
    • Evidence of clinical efficacy
    • Pressure of 16mmHg to 20 mmHg at the ankle in the supine position with graduated compression to the knee or above
    • Note: higher pressures may be ordered for GSC ordered for the treatment of chronic venous insufficiency.
  2. The use of GSC is contradicted in critical limb ischaemia
    • Avoid/use with extreme caution in the following conditions:
      • Skin diseases/dermatitis
      • Ligature of veins
      • Open ulcers
      • Severe arteriosclerosis.
  3. They must be measured and fitted for the individual patient.
    • Sizing range should be suitable for a large percentage of the population and the window of coverage should be clearly defined
    • The circumference and length of each extremity must be accurately measured according to the manufacturer’s instructions.
    • The stocking should fit snugly to maximise venous return – an appropriate fit is vital to prevent stocking from rolling down and forming a constrictive rubber-band like effect.
  4. They should be worn continuously during the period of immobility to the return of full ambulation.
    • The use of GCS should not impede ambulation
    • Note: Patients are at increased falls risk (risk of slipping) if not wearing appropriate footwear.
  5. Assessment of appropriate application and skin integrity must be undertaken at least once every shift
dvt_proph.txt · Last modified: 2026/01/18 08:57 by gary1

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