Pathology
What is a Venous Thrombi (VT)
Inflammation of a vein and formation of a thrombus
What is the Virchow Triad?
Three factors, are believed to play a significant role in the development of venous thrombosis:
Stasis of Blood
Vessel Wall Injury
Altered coagulation
Signs and symtoms are often nonspecific/asymptomatic
What is Heparin (coumadin)
Anticoagulant therapy is effective prophylaxis; however, anticoagulants do not dissolve a thrombus that has already formed.
What is Heparin-Induced Thrombocytopenia (HIT)?
sudden decrease in the platelet count by at least 30% of baseline levels in patients receiving heparin
What is the goal in treating a thrombus
Prevent the thrombus from growing and fragmenting (Risking PE) and to prevent recurrent thromboemboli
What happens in venous disorders that result in edematous tissue?
The thrombi or embolus obstructs the vein leading to decreased venous blood flow--> increased venous pressure -->increased capillary pressure, allowing filtration of fluid into the interstitial space-->tissue edema that is fragile and susceptible to breakdown, injury and infection
Explain how stasis of blood affects the formation of VT
Caused by immobility (bed rest, long plane/car/train rides, obesity, constrictive devices, paralysis, paresis, recent surgery, varicose veins, pregnancy), leads blood to remain stagnant and activate clotting factors
In monitoring for DVT what is the biggest indicator and how do you monitor it?
Unilateral leg edema r/t inhibition of venous outflow Measure leg- more than 3cm is clinically significant
How is Heparin adminstered?
SQ- NOT FIRST CHOICE IF CLIENT HAS A CLOT, typically used for prevention
IV- (prevents thrombus development/extension)- used for treatment: DOES NOT BREAK DOWN THE CLOT, PROLONGS Bleeding time
When does HIT occur?
What are some nursing interventions to prevent VT formation?
compression stockings- increase circulation
body positioning and exercise
anticoagulant therapy
Elevate limb
Apply warm moist packs PRN for comfort
Analgesia PRN
Assess pedal pulses
Activity as ordered or bed rest if fear of disloging
What are the three classifications of VT?
Deep
Thromboembolism
Explain how Vessel wall injury leads to VT
Caused by trauma (fractures, contusions), central venous catheterization, vascular devices (PICC, central lines, pacemaker wires), IV medications, cancer therapy (hormonal, chemotherapy, or radiotherapy
What are some other signs of VT that occur later in development?
-Tenderness, which usually occurs later, is produced by inflammation of vein wall, and firmness may be detected along the involved veins by gently palpating the affected extremity
How does Heparin Work?
Indirect thrombin inhibitor- Does not lyse or break up existing clot- prevents extension of a thrombus and development of new thrombi
How do you prevent HIT?
Regular Monitoring of Platelets
Normal 140-400
What patients are these interventions targeted?
Interventions to prevent thrombus formation are indicated in pts with:
thrombophlebitis
recurrent embolus formation
persistent leg edema from HF
pts who may require lengthy immobilization
What is a superficial venous thrombi?
Veins closer to the surface of extremities.
Can form from: IV with clot formation, swollen hard cord
Explain what causes Altered coagulation in the Virchow's triad
Caused by estrogen-containing oral contraception or hormone replacement, cancer (secretes procoagulants), smoking, dehydration, hypercoagulable states, late pregnancy, and the postpartum period
What are some clinical manifestations of Superficial vein thrombosis
= pain and tenderness/fullness, redness, warmth in the involved area, low grade fever
Homan's sign is not used anymore, it is unreliable.
What is Prothrombin time (PT)
measures how fast prothrombin turns into thrombin
-prolonged prothrombin time indicates deficiency in any of these- may mean pt has Vit K deficiency
What are early s/s of HIT?
decreasing platelet count
Need for increasing doses of heparin to maintain a therapeutic level
Thromboembolic or hemorrhagic complications
Skin discoloration consisting of hemorrhagic areas, hematomas, purpura, blistering
What are bleeding precautions?
Electric razor, no shaving, no rectal temps, soft toothbrushes, don’t blow nose hard, no contact sports, avoid IM injections, no NSAIDS/aspirin
What is a Deep Venous Thrombi
Thrombi located deeper in veins- trunk, limbs, pelvic area
-----RISK FACTORS-----
Which patients are at most risk for VT formation?
Pts with hx of varicose veins, hypercoagulation, neoplastic disease, cardiovascular disease, or recent major surgery or injury; obese, immobile, elderly, women taking oral contraceptives
What is the treatment for Superficial Vein Thrombosis
Many of these thromboses dissolve spontaneously- can be tx at home with bed rest, limb elevation, analgesics, anti-inflammatory medication.
NSAIDS NOT INDICATED-->increase in venous thromboembolism (VTE) caused by embolism breaking off and lodging in smaller vein
What is Activated Partial Thromboplastin Time (aPTT)
the test investigates bleeding disorders and to monitor pts taking an anticlotting drug such as heparin
Baseline: 21-35 seconds
Therapeutic Level = 1.5-2.5 x baseline
Critical Value >100 means there is a high risk for hemorrhage
What is Coumadin (Warfarin)?
oral anticoagulan
Admin soon after initiating heparin because may require 3-5 days to achieve a therapeutic effect.
Until a therapeutic INR is achieved, both Heparin and Coumadin are admin concurrently.
Once Coumadin demonstrates anticoagulant effectiveness, heparin can be d/c and pt maintained on oral coumadin
What s/s of bleeding are you monitoring for?
Look for bleeding from kidneys--> detected by microscopic examination of urine and is often the first sign of excessive dosage. Bruises, nosebleeds, bleeding gums also early signs
What is a Thromboembolism
when clot breaks off--> lungs (PE), heart (MI), brain (CVA)
-------VT GENERAL KNOWLEDGE------
What is Upper Extremity Thrombosis?
Thrombi that is less common than lower, however can occur in patients with IVs and underlying hypercoagulability disorder
What is the definitive diagnosis for VT?
Ultrasound
Unfractionated Heparin is at the therapeutic level when aPTT is at what value
1.5-2.5 x normal baseline
Goal 60-80 seconds
How does coumadin work
Vitamin K antagonist, suppresses synthesis of the active forms of clotting factors
Exhibits its anticoagulation effects via the intrinsic and extrinsic pathways in the clotting cascade
Which vitals should you monitor and what are their values
PT 11-13
aPTT 21-35
INR 2-3
Platelets 140-400k
Hct 36-48-Women and 42-52 Men
Hgb 12-16 Women and 14-17.4 Men
Fibrinogen 200-400
Vitamin K levels
What is an effort thrombosis
Thrombi caused by repetitive motion (competitive swimmers, tennis players, construction workers) that irritates vessel wall, causing inflammation and subsequent thrombosis
-----Coumadin-----
What foods should be avoided while on Coumadin?
Anything with lots of vitamin K
Leafy Greens, avocado, blueberries, soybeans, pumpkin
-----Thrombolytic Therapy---
What does Thrombolytic Therapy do?
lyses and dissolves thrombi
Alteplase, reteplase
What is the reversal agent for Unfractionated Heparin
Protamine Sulfate
Risks-> bradycardia, hypotension, administer slowly to minimize
What is monitored while a patient is on Coumadin?
Routine coagulation monitoring is essential- narrow therapeutic window, slow onset of action.
INR- Normal Value is 1, on Coumadin range is between 2-3, with 2.5 being the goal
What is a Venous Thrombi?
aggregates of platelets attached to the vein wall that have a tail-like appendage containing fibrin, WBCs, RBCs; can propagate as successive layers of thrombus form
Fragmentation can occur spontaneously or in association with elevated venous pressure, as when a person stands suddenly or engages in muscular activity after prolonged inactivity
-----Direct Thrombin Inhibitor-----
What is a direct thrombin inhibitor and what are the names of common meds?
Thrombin converts soluble fibrinogen to insoluble fibrin, while stimulating platelet activation; direct thrombin inhibitors (DTIs) impede this process
Desirudin, bivalirudin, argatroban (parenteral)- NO ANTIDOTE
Dabigatran (PO)- ANTIDOTE idarucizumab
What is Low-Molecular weight Heparin (Lovenox)
Longer half-lives than unfractionated so doses can be given in one or two SQ injections/day
Associated with fewer bleeding complications and lower risks of Heparin-Induced Thrombocytopenia than unfractionated heparin
How is coumadin given and what is the reversal agent?
Once INR is stable, levels are checked weekly for 2-4 weeks, then monthly
Pharmacist titrates coumadin based on morning blood draw for pt based on INR level
Reversal agent- VITAMIN K, infusion of fresh-frozen plasma or prothrombin concentrate.
Oral Vit K significantly reduces INR within 24 h; low-dose IV Vit K also effective