Flashcards in Session 15_DVT Deck (27)
List several complications associated with bed rest:
• Decubitus ulcers (injury to skin and underlying tissue resulting from prolonged pressure on the skin)
• Urinary infection
• Urostasis (stoppage of urination flow)
List several complications associated with surgery:
• atelectasis (complete or partial collapse of a lung or a section (lobe) of a lung)
• Sepsis (a life-threatening complication of an infection)
•multi system failure
What does thrombosis refer to? When does it occur?
• Thrombosis refers to "a condition" of a blood clot
• Thrombosis occurs with slowing or disruption of blood flow
• It is most frequently occurs in the calf ("the formation or presence of a blood clot in a blood vessel. The vessel may be any vein or artery as, for example, in a deep vein thrombosis or a coronary (artery) thrombosis. The clot itself is termed a thrombus.")
What can DVT turn into when the clot breaks off and travels to the lung circulation?
a traveling thrombosis =
Where do DVT occur?
deep veins of the leg (eg. iliac, femoral, popliteal, tibial)
List potential causes of a DVT:
• long flights
• immobility due to anesthesia/ post surgical
• oral contraceptives
•pressure to the calf
• disorder of clotting
• atrial fibrillation or other heart failure
•damage to a blood vessel
• post trauma
• congestive heart failure
What veins are implied when talking about DVT?
• Peroneal vein in the calf
• Femoral vein of the thigh
• Axillary or subclavian vein of the arm
• pelvic veins
How do you prevent DVT?
~ Prophylaxis ~
• compression hose
• SCDs (sequential compression device)
• Preventative anticoagulation e.g. coumadin
Despite prophylaxis, 31% of patients undergoing total knee replacement develop DVT, and 27% of patients operated on for hip fracture develop DVt. What alternative method has been shown to reduce incidence to 16%?
low-molecular weigth heparin prophylaxis
How are DVTs diagnosed?
• Ultrasound of the blood vessels
• Wells DVT criteria
• Homans sign (?) - (senstivity and specificity not optimal)
--> dorsiflexion/ resistance test
Describe the procedure of Doppler ultrasonography:
• A blood pressure cuff is wrapped around the pt's ankle
• A transducer with gel on it is placed over the pulse points of the foot and lower leg. High-frequency sound waves bounce off the soft tissue, and the echoes are converted into images on a monitor.
• This procedure is very accurate in detecting clots. Usually performed in a physicians' office or hospital outpatient diagnostic center.
Describe Well's criteria:
• Active caner? +1
• Bedrest >3 days or recent major surgery? +1
• Calf swelling >3cm compared to other leg? +1
• Entire leg swollen? Yes +1
• Calf tenderness along deep veins? +1
• Pitting edema, in the symptomatic leg? Yes +1
• Paralysis, paresis, or immobilization of the lower extremity? Yes +1
• Previous DVT? +1
• Alternative diagnosis to DVT likely? -2
How is Wells DVT criteria scored?
• High = >/- 3 points = DVT risk 75%
• Moderate = 1-2 points = DVT risk 17%
• Low =
Describe what D-Dimmer is and what a negative result implies:
• A blood test to help diagnosis DVT
• D-DIMER is a fibrin degradation product (FDP), a small protein fragment present in the blood after a blood clot is degraded
• Only present if the coagulation process has been activated
• A NEGATIVE result practically rules out thrombosis, a positive result can indicate thrombosis but does not rule out other potential causes
• Introduced in 1990
What are some signs and symptoms of DVT?
• Pain in the calf
• Calf swelling
• Well's criteria
• Positive Homans sign??
What are some complications of DVT?
• Most PEs result from DVT
• Piece of the thrombus breaks off, travels through the R side of the heart and into the pulmonary artery
• Can lodge in one of the smaller pulmonary capillaries
• Blockage to the pulmonary artery
Can you see a PE on a x-ray?
NO, can't see PE on x-ray
What are the signs and symptoms for when a DVT has become a PE (VTE)?
Symptoms = shortness of breath, cough, sharp/sudden chest pain
Signs = rapid pulse, hyotension, sweating, tachypnea, desaturation of the blood
Diagnosing PE; VQ (ventilation-perfusion) scan. Findings indicate what?
VQ scan finding = VQ mismatch in PE (high)
VQ mismatch in COPD, emphysema or atelectasis (low)
How do you prevent PE?
• Greenfield filter:
--> It is introduced through the jugular vein and is lodged in the inferior vena cava
--> Catches emboli
List some common pharmacological treatments of DVT/ pulmonary emoli:
• Anticoagulation such as: enoxaparin a.k.a. low molecular weight heparin (drug of choice since mid '90s)
• Standard unfractionated Heparin
• Coumadin aka. warfarin
(** note: while heparin does not break down clots that have already formed, it allows the body's natural clotlysis mechanisms to work normally to break down clots that have formed)
(After a DVT) when can a patient ambulate?
• When dose of anticoagulation is "theraputic"; usually within 6 hours
• Opinion varies by doctor
Recommendation from research: walk as soon and as much as possible with good compression therapy following anticoagulation therapy.
• Ambulation also leads to better outcomes: decreased pain, swelling and concurrence/severity of postthrombotic syndrome
see slide 25 for algorithm on ambulation
see slide 25 for algorithm on ambultation
When compared to bed rest, early ambulation was not associated with a higher incidence of a new PE. Furthermore, early ambulation was assocated with:
• lower new PE and new or progression of DVT
• lower incidence of new PE and overall mortality