peripheral vascular diseases edited

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PERIPHERAL VASCULAR DISEASE

OVERVIEW OF ANATOMY AND PHYSIOLOGYSTRUCTURE & FUNCTION OF BLOOD VESSELS BLOOD VESSELSchannels blood distributed to body tissues

WALLS OF AN ARTERY OR VEIN 3 LAYERS1- tunica intima 2-tunica media 3-tunica adventitia the pressure a vessel must endure determine thickness of the walls amount of connective tissue smooth muscle

DIVIDED INTO THE ARTERIAL & VENOUS SYSTEMARTERIAL SYSTEM high pressure vessels, Aorta- largest

branch into arterioles less than 0.5 mm in diameter functions to deliver blood to various tissues for nourishment contribute to tissue temperature regulation

VENOUS SYSTEM large diameter thin walled vessels less pressure

Leg veins contain valves regulate one-way flow

1.MUSCULAR PUMP Milking action of skeletal muscle contraction

2.RESPIRATORY PUMP Changes in abdominal and thoracic pressures occur with breathing

Functions to return blood from the capillaries to the right atrium for circulation acts as a reservoir for blood volume

CAPILLARIES

Connects arterioles and venules Permeable to gases and molecules exchanged between blood and tissue cells Found between in interwoven networks Filter and shunt blood from terminal arterioles to postcapillary venules

B. CIRCULATION AND DYNAMICS OF BLOOD FLOWBLOOD FLOW amount of fluid moved per unit of time through a vessel, organ or throughout the entire circulatory system

Systemic circulationsupplies nourishment to all of the tissue located throughout your body, with the exception of the heart and lungs because they have their own systems.

Systemic circulationmajor part of the overall circulatory system.

The blood vessels (arteries, veins, and capillaries) delivery of oxygen and nutrients to the tissue.

Oxygen-rich blood enters the blood vessels through the heart's main artery -- the aorta. The forceful contraction of left ventricle forces the blood into the aorta which then branches into many smaller arteries which run throughout the body.

inside layer of artery very smooth, allowing quick blood flow

outside layer of an artery very strong, allowing forceful blood flow.

The oxygen-rich blood enters the capillaries where oxygen & nutrients are released.

The waste products are collected waste-rich blood flows into the veins to circulate back to the heart Where pulmonary circulation will allow the exchange of gases in the lungs.

During systemic circulation, blood passes through the kidneys renal circulation

During this phase the kidneys filter much of the waste from the blood.

Blood also passes through the small intestine during systemic circulation. portal circulation.

During this phase the blood from the small intestine collects in the portal vein passes through the liver. The liver filters sugars from the blood, storing them for later.

BLOOD FLOW THROUGH THE HEART 1. deoxygenated blood returning from the body enters the heart through the superior vena cava and inferior vena cava.

2. blood passes into the right atrium and right ventricle

BLOOD FLOW THROUGH THE HEART

3. right ventricle pushes the blood through the pulmonary arteries

4. blood passes through the lungs where it loses carbon dioxide picks up oxygen

BLOOD FLOW THROUGH THE HEART

5. this oxygenated blood returns to the heart via the pulmonary veins

6. blood enters the left atrium and left ventricle

BLOOD FLOW THROUGH THE HEART

7. the left ventricle pushes the blood out through the main artery, the aorta

8. blood travels to all parts of the body where it delivers oxygen picks up carbon dioxide

FACTORS AFFECTING ARTERIAL 1. BLOOD VOLUME CIRCULATION Volume of blood transported in vessel, organ or throughout entire circulation in a given period of time

FACTORS AFFECTING ARTERIAL CIRCULATION

2. PERIPHERAL VASCULAR RESISTANCE [PVR] Opposing forces or impedance to blood flow as arterial channels are more distant from heart Determined by 3 factors Blood viscosity-thickness of blood Greater viscosity the greater resistance to moving & flowing

Length of vessel Longer the vessel the greater the resistance to blood flow

Diameter of vessel Smaller the diameter of vessel, the greater the friction against the walls of the vessel and greater impedance to blood flow

FACTORS AFFECTING ARTERIAL CIRCULATION

3. BLOOD PRESSURE Force exerted against the walls of arteries by blood Mean arterial pressure MAP Highest pressure Peak of venticular contraction or systole SYSTOLIC BLOOD PRESSURE

Lowest pressure Exerted during ventricular relaxation DIASTOLIC BLOOD PRESSURE

MEAN ARTERIAL PRESSURE [MAP]:MAP= CO [cardiac output] X PVR Estimated clinical calculation of MAP DBP + 1/3 OF PULSE PRESSURE (DIFFERENCE BETWEEN SYSTOLIC AND DIASTOLIC BLOOD PRESSURE)

FACTORS AFFECTING ARTERIAL CIRCULATION

3. BLOOD PRESSURE OTHER FACTORS REGULATING BP 1. SYMPATHETIC AND PARASYMPATHETIC NS SYMPATHETIC stimulation Vasoconstriction of arterioles Increasing BP

FACTORS AFFECTING ARTERIAL CIRCULATION

3. BLOOD PRESSURE OTHER FACTORS REGULATING BP 1. SYMPATHETIC AND PARASYMPATHETIC NS PARASYMPATHETIC stimulation Vasodilation of arterioles Lowering BP

FACTORS AFFECTING ARTERIAL CIRCULATION

3. BLOOD PRESSURE OTHER FACTORS REGULATING BP 1. SYMPATHETIC AND PARASYMPATHETIC NS BARORECEPTORS & CHEMORECEPTORS (in aortic arch, carotid sinus and other large vessels Sensitive to pressure and chemical changes causing REFLEX SYMPATHETIC STIMULATION vasoconstriction increased HR & BP

FACTORS AFFECTING ARTERIAL CIRCULATION

3. BLOOD PRESSURE OTHER FACTORS REGULATING BP 2. ACTION OF KIDNEYS TO EXCRETE OR CONSERVE SODIUM AND WATER Kidneys initiate renin-angiotensin mechanism in response to decrease in BP Release of aldosterone from adrenal cortex Sodium ion reabsorption & water retention

Kidneys reabsorb water in response to pituitary release of antidiuretic hormone Increase in blood volume Increase CO & BP

FACTORS AFFECTING ARTERIAL CIRCULATION

3. BLOOD PRESSURE OTHER FACTORS REGULATING BP 3. TEMPERATURE Cold Vasoconstriction

Warmth Vasodilation

4. CHEMICALS, HORMONES, DRUGS Vasoconstriction Epinephrine Endothelin [chemical fr.bld vsl inn lining] Nicotine

Vasodilation Prostaglandin Alcohol & histamine

FACTORS AFFECTING ARTERIAL CIRCULATION

3. BLOOD PRESSURE OTHER FACTORS REGULATING BP 5. DIETARY FACTORS Salt Saturated fat Cholesterol

6. OTHER FACTORS Race Gender Age Weight Time of day Position Exercise Emotional state

DIANOSTIC TEST AND ASSESSMENT

DOPPLER ULTRASOUND measures the velocity of the blood flow through a vessel emits an audible signal when arterial palpation is difficult or impossible because of occlusive disease useful in determining blood flow

DIAGNOSTIC TESTS AND ASSESSMENT

palpable pulse & Doppler pulse are not equivalent & should not be used interchangeably

biologic changes in volume in a portion of the body associated with cardiac contractions or in response to pneumatic venous occlusion

PLETHYSMOGRAPHY

can detect & quantify vascular disease changes in pulse contour, blood pressure. or arterial /venous blood flow

A plethysmography test is performed by placing blood pressure cuffs on the extremities to measure the systolic pressure The cuffs are then attached to a pulse volume recorder (plethysmograph) that displays each pulse wave.

The test compares the systolic blood pressure of the lower extremity to the upper extremity, to help rule out disease that blocks the arteries in the extremities

utilizing computer technology visualization of blood vessels occurs after IV injection of contrast material

DIGITAL INTRAVENOUS ANGIOGRAPHY

allows for small peripheral venous injections of contrast medium, compared with large doses that must be injected via arterial cannulation

DIGITAL INTRAVENOUS ANGIOGRAPHY

VENOGRAPHY injection of radiopaque dye into veins serial x-rays are taken to detect deep vein thrombosis and incompetent valves

ANGIOGRAPHY injection of radiopaque dye into arteries to detect plaques, occlusions, injury, etc

most commonly used parameter for overall evaluation of extremity status

ANKLE-BRACHIAL INDEX

ankle pressure normally is the same or slightly higher than brachial systolic pressure expected ABI is 0.8 to 1.0

ANKLE-BRACHIAL INDEX

gives the ratio of the systolic blood pressure in the ankle to the systolic blood pressure in the brachial artery of the arm

COMPUTED TOMOGRAPHY

allows for visualization of the arterial wall and its structures

used in the diagnosis of abdominal aortic aneurysm [AAA] and postoperative vascular complications graft occlusion hemorrhage

MAGNETIC RESONANCE IMAGING [MRI]

uses magnetic fields rather than radiation used with angiography to detect abnormalities especially in people who are unable to have dye injected

MRI

COMMON NURSING A. BLOOD PRESSURE TECHNIQUES AND is primarily a PROCEDURES: BLOOD function of cardiac PRESURE MEASUREMENT output and systemic vascular resistance B. ARTERIAL BLOOD PRESSURE= CARDIAC OUTPUT X SYSTEMIC VASCULAR RESISTANCE

1. Client seated with arm bared, supported and at heart level

C. PROPER TECHNIQUE

2. Client should not have smoked or ingested caffeine 30 minutes prior

3. BP taken in both arms initially

4. Appropriate sized cuff must be used rubber bladder should encircle the arm by 80%