Peripheral System - Chapter 21

What does a complete blockage lead to?

death of the distal tissue

What does a partial blockage create?

insufficient supply, and the ischemia may be apparent only at exercise when oxygen needs increase

What does Peripheral Artery Disease affect?

Noncoronary arteries and usually refers to arteries supplying the limbs

What is PAD usually caused by?

Atherosclerosis and less commonly by embolism, hypercoagulable state, or arterial dissection

Course of Veins and Arteries

Parallel to each other, flow in opposite directions

What do the Veins absorb?

CO2 and waste products from the periphery and carry them back to the heart.

What veins are accessible for examination?

• Jugular Veins

• Veins in the arms

• Veins in the legs

What are the Veins in the Arm?

each has two sets of veins:

• Superficial and deep. Superficial veins are in the subcutaneous tissue and are responsible for most of the venous return

What are the Veins in the legs?

have three types of veins:

• Deep Veins

• Superficial Veins

• Perforators

What are the Deep Veins in the legs?

run alongside the deep arteries and conduct most of the venous return from the legs.

• These are called the femoral and popliteal veins.

• As long as these veins remain intact, the superficial veins can be excised without harming the circulation

What are the Superficial Veins of the Leg?

These are the great and small saphenous veins. Blood flows from these veins into the deep leg veins.

Where are the Great Saphenous Vein?

inside the leg, starts at the medial side of the dorsum of the foot.

• can be seen ascend the front of the medial malleolus; then it crosses the tibia obliquely and ascends along the medial side of the thigh

Where are the Small Saphenous Vein?

outside of the leg, starts on the lateral side of the dorsum of the foot and ascends behind the lateral malleolus, up the back of the leg, where it joins the popliteal veins.

What are Perforators?

connecting veins that joins the two sets.

• have one way valves that route blood from the superficial into the deep veins and prevent reflux to the superficial veins

What do veins drain?

deoxygenated blood with its waste products from the tissues and returns it to the heart.

What kind of pressure system do veins have?

low pressure system; because they do not have a pump to generate their blood flow and they need a mechanism to keep the blood moving

How do veins accomplish the movement of blood?

• contracting skeletal muscles that milks the blood proximally

• Pressure gradient caused by breathing, in which inspiration makes the thoracic pressure decrease and abdominal pressure increase.

• Intraluminal Valves which ensure unidirectional flow

What are the valves of the veins and what do they do?

each valve is a paired semilunar pocket that opens toward the heart and closes tightly when filled to prevent backflow of blood

What is the mechanism for blood for in the legs?

Cald pump or peripheral heart

What is calf pump or peripheral heart?

When walking, the calf muscles alternately contract (systole) and relax (diastole).

• In the contraction phase, the gastrocnemius and soleus muscles squeeze the veins and direct the blood flow proximally.

What are the differences in the structure in Veins compared to arteries?

• Walls of veins are thinner

• Have a larger diameter

• More distensible (can expand and hold more blood)

Why are veins called “Capacitance Vessels?

Because of their ability to stretch and hold more blood when blood volume increase.

• Their compensatory mechanism to reduce stress (preload) on the heart

What does Efficient venous return depend on?

Contracting skeletal muscles, competent valves in the veins, and a patent lumen

What problems can arise with unefficient venous return?

Can lead to venous stasis

Who is at risk for venous disease?

People who undergo prolonged standing, sitting, or bed rest because they do not benefit from the milking action that walking accomplishes

What are other risk factors for venous disease?

Hypercogulable states and vein wall trauma

What causes incompetent valves?

dilated and tortuous (varicose) veins; wherein the lumen is so wide that the valve cusps cannot approximate

Venous pooling occurs in which people?

People with obesity and women following multiple pregnancies

Any disease in the vascular system impairs ____________.

the delivery of oxygen and nutrients to the affected cells and retards the elimination of carbon dioxide and waste products from cellular metabolism

The heart pumps freshly oxygenated blood through

the arteries to all body tissues.

Arteries contain what?

elastic fibers - which allow their walls to stretch with systole and recoil with diastole.

• muscle fibers (vascular smooth muscle - VSM

Vascular Smooth Muscle

controls the amount of blood delivered to this tissues

• contracts or dilates, which changes the diameter of the arteries to control the rate of blood flow

Each heartbeat creates what?

a pressure wave, which makes the arteries expand and then recoil

• it is the recoil that propels blood through like a wave.

Palpation - Temporal Artery

palpated in front of the ear

Palpation - Carotid Artery

Palpated in the groove between the sternomastoid muscle and the trachea

Palpation - Arteries in the Arm

Major supplying artery is the brachial artery which runs in the biceps-triceps furrow of the upper arm and surfaces at the antecubital fossa in the elbow to the biceps tendon

Radial Pulse location

lies just medial to the radius at the wrist

Ulnar Artery location

same relation to the ulna, but it is deeper and often more difficult to feel

Major artery of the Leg

Femoral artery, which passes under the inguinal ligament and travels down the thigh.

Posterior tibial Artery

travels down behind the medial malleolus and forms the plantar arteries in the foot. F

What is the Function of the Arteries?

To supply oxygen and essential nutrients to the cells

What is Ischemia?

Deficient supply oxygenated arterial blood to a tissue caused by the obstruction of a blood vessel.

Weak, “Thready” Pulse - 1+

hard to palpate, need to search for it, may fade in and out, easily obliterated by pressure

Full, Bounding, Pulse - 3+

easily palpable, pounds under your fingertips

• Associated with: Hyperkinetic states (exercise, anxiety, fever, anemia, hyperthyroidism

Water-Hammer (Corrigan) Pulse - 3+

Greather than normal force, then collapses suddenly

• Associated with: aortic valve regurgitation, patent ductus arteriosus

Pulse Bigeminus

Rhythm coupled, every other beat comes early, or normal beat followed by premature beat; force of premature beat decreased because of shortened cardiac filling time

• Associated with: Conduction Disturbance (e.g Premature ventricular contraction, premature atrial contraction)

Pulses Alterans

Rhythm regular, but force varies, with alternating beats of large and small amplitude

Pulses Paradoxus

Beats have weaker amplitude with inspiration, stronger with expiration; best determined during blood pressure measurement; reading decreases (>10mmHg) during inspiration and increases with expiration.

Pulses Bisferiens

Each pulse has two strong systolic peaks with a dip in between; best assessed at the carotid artery

Raynaud Phenomenon

Episodes of abrupt, progressive tricolor change of the fingers in response to cold, vibration, or stress.

• 3 phases

• Duration: 15-20 mins after rewarming

• Management: rewarm

  • long term: avoid smoking

• Red flags: onset after age 30, male sex, unilateral (one sided symptoms)

Raynaud Phenomenon - Phases

• White (pallor): Vasoconstriction/Ischemia - numbness

• Blue (Cyanosis: oxygen extraction - pain/aching

• Red (Rubor): reactive hyperemia/rewarming (burning/throbbing)

Aneurysms

a sac formed by dilation in the artery wall.

• Atherosclerosis weakens the middle layer (media) of the vessel wall.

Lymphatics Systems

vessel system that retrieves excess fluid and plasma proteins from the interstitial spaces and returns them to the bloodstream.

• fluid moves according to a pressure gradient (filtration)

Arterial end of lymphatics system

hydrostatic pressure is caused by the pumping action of the heart and pushes somewhat more fluid out of the capillaries than the venules can absorb.

Without lymphatic drainage, what would happen?

fluid would build up in the interstitial spaces and produce edema

Right Lymphatic Duct drains what?

empties into the right subclavian vein; drains the right side of the head and neck, right arm, right side of the thorax, right lung and pleura, right side of the heat, and right upper section of the liver

Thoracic Duct drains what?

the rest of the body. It empties into the left subclavian vein

What is the function of the lymphatic System?

• conserve fluid and plasma proteins that leak out of the capillaries

• form a major part of the immune system that defends the body against disease

• absorbs lipids from the small intestines

The Flow of lymph is __________.

Slow compared to that of the blood.

• Lymph flow is propelled by contraction of the skeletal muscles

• pressure changes secondary to breathing

• contraction of the vessel walls

Lymph nodes

small, oval clumps of lymphatic tissue located at intervals along the vessels.

• most nodes are arranged in groups, both deep and superficial

What do Nodes do?

filter fluid before it is returned to the bloodstream and filter out microorganisms that could be harmful to the body.

Cervical nodes drain ___________.

the head and neck

Axillary nodes drain __________.

the breast and upper arm

Epitrochlear node drains ___________.*

the hand and lower arm.

• it is in the antecubital fossa

Inguinal node drains __________.*

most of the lymph of the lower extremities, the external genitalia, and the anterior abdominal wall

What related organs aid the lymphatic system?

spleen, tonsils, and thymus

What are the functions of the Spleen and location?

Located in LUQ:

• Destroy old red blood cells

• Produce antibodies

• Store red blood cells

• Filter Microorganisms

Tonsils (Palatine, Adenoid, and Lingual)

located at the entrance to respiratory and gastrointestinal tracts and responds to local inflammation

Thymus

flat, pink-gray gland located in superior mediastinum behind sternum and in front of aorta

• important with T lymphocytes

Arteriosclerosis

peripheral blood vessels that grow more rigid with age, producing a rise in systolic blood pressure.

What is Intermittent Claudification?

pain in a specific muscle group that is brought on by walking and is relieved with rest.

• impairs walking distance

• Feels like a cramp and is usually relieved by rest within 2 minutes.

Aging produces a progressive enlargement of what?

intramuscular calf veins

What can increase the risk for DVT?

Prolonged bed rest, prolonged immobilization, and chronic disease (e.g heart failure, chronic kidney disease, cancer, liver disease)

Aging adults have a loss of what?

lymphatic tissue leading to fewer number of lymph nodes and decrease in the size of the remaining lymph nodes

Night Pain is common in aging adults and may indicate what?

the Ischemic rest pain of peripheral vascular disease.

• Alterations in arterial circulation cause pain that becomes worse with leg elevation and is eased when the extremity is dangled.

50% of the causes of PAD can be attributed to:

• smoking

• DM

• Dyslipidemia (high cholesterol)

• HTN

What is the highest group with PAD?

non-Hispanic Blacks

With PAD, blood flow cannot match muscle demand during exercise; therefore ____________.

people feel muscle fatigue or pain when walking (claudication), but only 10% of those with PAD have this classic symptom

What is Claudication Distance?

the number of blocks walked or stairs climbed to produce pain

Night Leg Pain is common in aging adults, indicating what?

the ischemic rest pain of PAD, severe night muscle cramping (usually calf) or restless legs syndrome.

What is Aortoiliac Occlusion associated with?

Erectile dysfunction (Leriche Syndrome)

Risk factors for PVD

Diabetes and smoking are stronger risk factors for this than they are even for heart diseases

What should be avoided with PAD?

Compression stocking since they further impede blood flow.

• they are indicated to prevent leg swelling in standing workers or thrombus formation

Why do Leg Ulcers occur with>

chronic arterial and venous disease

When is Edema Bilateral?

when the cause is generalized (heart failure)

When is Edema unilateral?

when it is the result of a local obstruction or inflammation

What causes Enlarged Lymph nodes?

infection, malignancies, and immunologic diseases

Medications can cause what?

Hypercoagulable state

• low-dose aspirin or clopidogrel; is used to prevent blood clots in selected people

Why do we want to know about smoking history?

Because it constricts arteries, increases coagulability, injures endothelium and promotes inflammation

• starting smoking <16 doubles future PAD risk

We use profile sign to detect what?

early clubbing (viewing the finger from the side)

• the normal nail angle is 160 degrees

When we have the person’s hands near the level of his/her heart, what do we check?

capillary refill.

What does capillary refill indicate?

it is an index of peripheral perfusion and cardiac output.

Flattening of angle and clubbing occurs because of what?

Congenital Cyanotic Heart disease and Cor Pulmonale

If capillary refills lasts more than 2 seconds, what could it signal?

vasoconstriction or decreased cardiac output (hypovolemia, heart failure, shock)

• the hands are cold, clammy, and pale

Edema of Ipsilateral upper extremity occurs because of what?

when lymphatic drainage is obstructed after breast surgery or radiation

When would we palpate the brachial artery?

If we suspect arterial insufficiency - their force should be equal bilaterally

Where do we check for epitrochlear lymph nodes?

in the depression 2 or 3 cm above and behind the medial condyle of the humerus

• Do this by shaking hands with the person and reaching your other hand under the elbow to the groove between the biceps and triceps muscles.

• these nodes are NOT normally palpable

Enlarged Epitrochlear nodes occur with?

infection of the hand or forearm.

• occurs in conditions of generalized lymphadenopathy; lymphoma; chronic leukemia; infectious mononucleosis; HIV Infection

What is the modified Allen test used for?

to Evaluate the adequacy of collateral circulation before cannulating the radial artery.

• Press both ulnar and radial arteries and have pt make a fist

• have pt release hand, hand blanches, release ulnar artery while maintaining pressure on radial artery

• Adequate circulation is suggested by palmar blush

What are some limitation of the modified Allen test?

it is subjection and requires patient cooperation that may not occur in emergency or critical care situations