Hemostasis, DVT, PE, Anticoagulation SG

hemostasis

the arrest of bleeding, a process important to minimizing blood loss when body structure are injured

hematology

study of blood and blood forming tissue

hematocrit

plasma 55%, the rest is other components

normal clotting mechanism

initiated through one of two pathways, intrinsic or extrinsic

clotting process

vascular injury, vasoconstriction, and subendothelial exposure

adhesion

activation of clotting cascade

formation of a blood clot, aggregation

platelet plug formation

clot retraction and dissolution

aging effects on clotting

changes in bone marrow, Hgb levels, vascular integrity, and blood cell responsiveness and reserves

diminishes ability of older adults to recover from acute illness or compensate for chronic diseases

why is thrombus formation important to achieve hemostasis?

the final blood clot stabilizes the platelet plug and traps other cells, such as RBCs, phagocytes, and microorganisms

adhesion

the loss of endothelial cells exposes adhesive glycoproteins to which more platelets adhere

aggregation

the formation of platelet plugs

activation

the actions so far cause the platelets to undergo activation process which causes them to change shape and bind adhesive proteins

clot retraction and dissolution

counter mechanism of blood clotting that keeps blood in its fluid state

venous thrombosis

involves the formation of a thrombus with vein inflammation, most common disorder of the vein

VTE develops from hereditary and acquired risk factors

virchow's triad

vessel wall injury, venous stasis, and hypercoagulability is central to understanding thrombosis

venous thrombosis process

mechanical or physiologic vessel wall damage activates platelets, causing them to stick together and form a clot

thrombus may dissolve naturally or enlarge, eventually obstructing blood flow, dilating veins, and promoting additional clot formation

venous thrombosis detection

approximately 50% of people are asymptomatic, detection is challenging

risk factors for VTE

venous stasis, endothelial damage, hypercoagulability of blood

venous stasis

occurs when the valves are dysfunctional or the muscles of the extremities are inactive

common in people who are obese or pregnant, have chronic HF or A Fib, have been traveling on long trips, or are immobile for long periods of time

endothelial damage

may be caused by direct or indirect injury, stimulates platelet activation and starts the coagulation cascade, this predisposes the patient to thrombus development

direct endothelial damage

surgery, intravascular catheterization, trauma, burns, prior VTE

indirect endothelial injury

chemotherapy, diabetes, sepsis

hypercoagulability of blood

occurs with many problems that includes severe anemias, polycythemia, cancers, nephrotic syndrome, high homocysteine levels, and proteins C, S, and antithrombin deficiency

superficial vein thrombosis manifestations

palpable, firm, subcutaneous cordlike vein, area around vein may be itchy, painful to touch, reddened, or warm

mild temp elevation and leukocytosis may be present

extremity edema may occur, lower extremity SVT often includes varicose veins

SVT risk factors

increased age, pregnancy, obesity, cancer, recent fracture, estrogen therapy, recent sclerotherapy, recent surgery or long distance travel, hypercoagulability, and history of chronic venous insufficiency

SVT care

ultrasound to confirm, anticoagulants may be needed

graduated compression stockings or bandages, apply warm compresses, elevate affected limb above heart, apply topical NSAIDs, and perform mild exercise such as walking

Deep vein thrombosis

serious condition where blood clot forms in a deep vein, usually in the legs or the pelvis region

DVT manifestations

swelling, pain and tenderness, warmth, redness/discoloration, swollen veins

DVT complications

PE, post thrombotic syndrome, recurring DVT

DVT risk factors

long term bed rest, hospitalization or travel, injury/surgery, cancer, HF, inflammatory bowel, obesity, smoking, pregnancy, and oral contraceptives

DVT care

anticoagulants, compression stockings, inferior vena cava cilter, thrombolytic agents

proximal DVTs

have a higher chance of breaking off and causing a PE

most DVTs

occur in lower extremities but some occur in upper

VTE manifestations

unilateral leg edema, pain, tenderness with palpation, dilated superficial veins, sense of fullness in the thigh or calf, paresthesias, warm skin, redness, or systemic temp greater than 100.4 degrees

VTE complications

pulmonary embolism, chronic thromboembolic pulmonary hypertensions, post thrombotic syndrome, and phlegmasia cerulea dolens

VTE diagnostics

based on assessment combined with D-dimer testing and ultrasound

blood: ACT, aPTT, INR, bleeding time, Hgb, Hct, platelet count, D-dimer, fibrin monomer complex

noninvasive: venous compression ultrasound and duplex ultrasound

invasive CT venography, MRI venography, contrast

VTE care

prevention drug therapy, surgery or radiologic therapies

early and progressive mobilization, graduated compression stocking, intermittent pneumatic compression devices

venous thromboembolism

detached thrombus results in embolus, travels through the venous system to right side of heart and lodges in pulmonary circulation, becomes PE

post thrombotic syndrome symptoms

pain, aching, fatigue, heaviness, sensation of swelling, cramps, pruritus, tingling, paresthesia, bursting pain with exercise, and venous claudication

PTS manifestations

persistent edema, spider veins, venous dilation, redness, cyanosis, increased pigmentation, eczema, pain during compression, atrophic blanche, and lipodermatosclerosis

pulmonary embolism

sudden, life threatening blockage in one of the pulmonary arteries in the lungs

PE diagnosis

CT pulmonary angiography is gold standard, D-dimer blood test, chest x-ray, venous ultrasound, ventilation perfusion scans

PE treatment

aims to stop the clot from getting bigger and prevent new formation, anticoagulants or thrombolytics in severe cases, procedures to remove the clot

heparin

IV or SubQ, indirect thrombin inhibitor, IV given as adjunct for existing blood clots, SQ given prophylactically to prevent development of clots, affects intrinsic plasma antithrombin coagulation pathway; inhibits thrombin mediated conversion of fibrinogen to fibrin

heparin considerations

effects measured at regular intervals with aPTT, or ACT, monitor CBC, administration guidelines

LMWH considerations

monitor CBC, reduced dosage in pt with renal problems or history of HIT prophylaxis given SQ, existing VTE give continuous IV, monitor aPTT, more predictable, long half-life, fewer bleeding complications

LMWH

SQ, indirect thrombin inhibitor

heparin side effects

HIT, long term osteoporosis

warfarin

oral, k=long term extended anticoagulation

inhibits activation of vitamin K dependent coagulation factors II, VII, IX, and X as well as anticoagulant proteins C and S

warfarin considerations

INR used to monitor therapeutic levels, same time each day, variations of certain genes may influence response to drug

takes 48-72 hours to be effective, often overlapping with parenteral anticoagulants for 5 days

do not give with NSAIDs or antiplatelet drugs, avoid changing intake of vitamin K in diet because it alters INR

dabigatran

oral direct thrombin inhibitor used for VTE prevention after elective joint replacement, for stroke prevention in nonvalvular A fib, and as a treatment for VTE

dabigatran considerations

rapid onset, no need to monitor anticoagulation, few food-drug interactions, lower risk for major bleeding, and predictable dose response

idarucizumab

dagibatran antidote

rivaroxaban and apixaban

inhibit factor Xa directly or indirectly, producing rapid anticoagulation

used for both VTE preventions and treatment

direct factor Xa inhibitors considerations

coagulation monitoring or dose adjustment not needed, anticoagulant activity measured using anti Xa assays

adnexant alfa

reverses actions of direct Xa inhibitors

aspirin

irreversibly inhibits COX-1, prevents platelet aggregation, used for MI and stroke prevention and acute coronary artery syndrome

aspirin considerations

monitor for bleeding, GI risk factors, hold before surgery, avoud in children

P2Y12 ADP receptor antagonists

clopidogrel and ticagrelor, block ADP receptors on platelets preventing activation, clopidogrel requires liver activation and ticagrelor has a faster onset with no liver activation required

clopidogrel considerations

bleeding, avoid with omeprazole

ticagrelor considerations

dyspnea

tirofiban

blocks final pathway of platelet aggregation, used during PCI, unstable angina, and high risk ACS

tirofiban considerations

given IV, continuous cardiac monitoring, high bleeding risk, and monitor platelet count

alteplase

recombinant tissue plasminogen activator used for acute ischemic stroke, STEMI, and massive PE

reteplase

modified tPA, used primarily for STEMI

tenecteplase

long half-life, given as a single IV bolus, used for STEMI

thrombolytics considerations

active bleeding absolute contraindication, monitor neuro status, signs of internal bleeding, and Hgb/Hct, avoid IM injections, limit venipunctures, no invasive procedures during infusion

hospitalization patient not bleeding

UH, LMWH, or fondaparinux

low risk VTE

no prophylaxis

moderate risk

UH or LMWH, trauma, abdominal or pelvic surgery for cancer, or orthopedic surgery

VTE surgery

open venous thrombectomy, inferior vena cava interruption devices

open venous thrombectomy

incision into vein to remove clot

inferior vena cava interruption devices

filters places via right femoral or internal jugular veins, trap clots without impeding blood flow, recommended for acute PE or proximal VTE of leg with active bleeding or if anticoagulation is contraindicated or ineffective

IVCID complications

air embolism, improper placement, filter migration, perforation of vena cava with retroperitoneal bleeding, clogged filter

VTE interventional radiology therapies

mechanical thrombectomy, pharmacomechanical devices, post thrombus extraction, angioplasty, and/or stenting

can be used with catheter directed thrombolytic therapy

VTE radiology nursing cares

maintain catheter systems, monitor for bleeding, embolization, and impaired perfusion, teach VTE prevention

clotting cascade