Week 15: Vascular Disorders

acute arterial ischemia

a sudden lack of blood flow to an area due to a blockage in an artery. It can lead to tissue damage and requires immediate medical attention to prevent serious complications.

atheroma

The fatty material that clogs your arteries. It builds up over time and can lead to complications. Also known as plaque, it is the defining feature of a disease called atherosclerosis.

critical limb ischemia

a severe blockage in the arteries of the lower extremities, which markedly reduces blood-flow. It is a serious form of peripheral arterial disease, or PAD, but less common than claudication.

hypercoagulability

Also known as, hrombophilia is the increased tendency of blood to thrombose. A normal and healthy response to bleeding for maintaining hemostasis involves the formation of a stable clot, and the process is called coagulation.

intermittent claudication

pain affecting the calf, and less commonly the thigh and buttock, that is induced by exercise and relieved by rest. Symptom severity varies from mild to severe. Intermittent claudication occurs as a result of muscle ischaemia during exercise caused by obstruction to arterial flow.

peripheral artery disease (PAD)

a common condition in which narrowed arteries reduce blood flow to the arms or legs. In peripheral artery disease (PAD), the legs or arms — usually the legs — don't receive enough blood flow to keep up with demand.

• Primarily caused by atherosclerosis

• Predisposing factors include:

  • Smoking

  • Diabetes

  • Hypertension

  • Atherosclerosis.

  • High cholesterol.

  • Age above 60 years

• Common complications:

  • Infections

  • Delayed wound healing

  • Gangrene

  • Necrosis

  • Amputation.

• Dx:

  • ankle-brachial index (ABI).

  • duplex Doppler ultrasound.

Vascular

relating to, affecting, or consisting of a vessel or vessels, especially those which carry blood

venous stasis

Refers to the slowing or pooling of blood in the veins, often due to impaired circulation. It can lead to conditions like varicose veins or venous ulcers.

venous thromboembolism (VTE)

A condition that occurs when a blood clot forms in a vein. VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT occurs when a blood clot forms in a deep vein, usually in the lower leg, thigh, or pelvis.

• Causes + Risk factors - Virchow’s triad

  • Endothelial (blood vessel) injury

  • Stasis or turbulence of blood flow

  • Hypercoagulability of blood

• Signs and Symptoms (not an O2 issue)

  • calf pain.

  • Leg edema (may or may not be unilateral)

  • Redness - that leg will feel warm.

  • Pain and tenderness on palpation.

  • Positive Homans sign - the patient experiences calf pain on forced dorsi flexion of the foot when the leg is raised.

• Dx:

  • Thromboplastin time

  • INR

  • Hemoglobin hematocrit

  • CBC differential

  • D-dimer

• Complications

  • Pulmonary embolus which is a life-threatening emergency.

venous thrombosis

The formation of a blood clot within a vein, typically in the legs. It can lead to serious complications like pulmonary embolism. Treatment may involve anticoagulant therapy.

Virchow’s triad

1. Endothelial (blood vessel) injury

2. Stasis or turbulence of blood flow

3. Hypercoagulability of blood

These factors contribute to the formation of blood clots.

Consequenses of Hypoxia in a lower limb

• Ulcers

• Gangrene, which is a bacterial infection

• Necrosis.

Total Occlusion

When a blood vessel gets completely blocked or closed off. It can occur from a thrombus completely blocking the blood vessel lumen or an embolus, which is a clot that breaks off and eventually blocks a smaller vessel.

Ankle brace ankle-brachial index

A test that is performed using the handheld Doppler to determine if there is a difference in bp between upper extremities and lower extremities.

The ankle-brachial index is calculated by dividing the ankle systolic blood pressure and the brachial systolic blood pressure.

Pharmelogical Interventions for PAD

• Anti-platelet medications to prevent clots

• ACE inhibitors for blood pressure

• Vasodilators tohelp open up the blood vessels and allow blood flow to the extremity.

Pulmonary Embolus

A blockage in one of the pulmonary arteries in the lungs is usually caused by blood clots travelling to the lungs from the legs or other parts of the body.

Thrombin

An enzyme in the blood that helps in the clotting process by converting fibrinogen into fibrin, which forms blood clots to stop bleeding.

D-miner Blood test

A blood test that checks for blood-clotting problems. It measures the amount of D-dimer, a protein your body makes to break down blood clots. A positive test means the D-dimer level in your body is higher than normal. It suggests you might have a blood clot or blood clotting problems. It is used in the diagnosis of DVT.

fibrin monomer complex

The formation of thrombin exceeds the time it takes for antithrombin to form. So if thrombin is able to form faster than antithrombin, that also suggests a venous thromboembolic event

the duplex ultrasound

A combination of compression and colour flow doppler. And so the veins are examined looking for variations and compressibility. It’s normal for the veins to collapse with application of an external pressure, if they then that might indicate a DVT. Also looking at trans luminal filling defects to determine the location of a thrombus and the extent of it, how bad it is.

The duplex ultrasound is the most widely used test to diagnose a deep vein thrombosis because of its accuracy

Invasive venous studies for dx of DVT

• Computed tomography venography.

  • a contrast medium is injected into the veins. And then that contrast medium will show up where the clot is

• Magnetic resonance venography.

  • Can be done with or without a contrast. It's very accurate for detecting clots in proximal veins, but it's less accurate for detecting clots in calf veins.

  • It can distinguish between acute and chronic blood clots.

• Contrast venography (phlebogram).

Pharmelogical care for DVT

• Anticoagulants such as low molecular weight heparin and warfarin

  • Heparin affects the intrinsic clotting pathway, can be administered subcutaneously or IV, and does not cross the placenta. Overall less drug interactions.

    • antidote for heparin is protamine sulfate

  • Warfarin affects the extrinsic pathway, administered PO only, Teratogenic

    • antidote for warfarin is vitamin K

superficial vein thrombosis

A blood clot in a superficial vein, typically in the legs. It can cause pain, redness, and swelling. Treatment may involve compression stockings and pain relief medication.

deep vein thrombosis

A blood clot (thrombus) forms in one or more of the deep veins in the body, usually in the legs. Deep vein thrombosis can cause leg pain or swelling. Sometimes there are no noticeable symptoms.

oral contraceptives and deep vein thrombosis

The majority of clotting factors come from the liver, but there is a small amount of clotting factors that are made in the bone marrow.

The excess estrogen in the oral birth control pills stimulates the megakaryocytes in bone marrow to make too many clotting factors. And then the clotting factors go into the bloodstream and then that increases blood clotting and the risk for venous thromboembolism.

Evidence-based nursing interventions to prevent deep vein thrombosis in hospitalized patients.

• Encourage early postoperative ambulation

• Calf pumping when the patient is in bed.

  • Moving the foot forward and backward, up and down, and flexing at the ankle will get the blood flowing in the veins.

• Encourage our hospitalized patients to take in a healthy amount of fluids, 2-3 litres per day.

• Turn and position are immobile patients frequently every two hours around the clock.

• Any measures we can take to promote circulation in our patients

• Thrombin or thromboembolic stockings