Chapter 21: Peripheral Vascular System and Lymphatic System

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Welcome back.

If you're listening to this right now, I know exactly who you are.

You're a college nursing student.

Exactly.

You're a nursing student.

You probably have this massive, heavy textbook staring you down and you're just looking for a way to make this really dense material actually stick in your brain.

And you are in the exact right place for that.

Yeah, because the mission for this deep dive is crystal clear.

We are going to help you completely master Chapter 21, that's the peripheral vascular system and lymphatic system, from your physical examination and health assessment text.

Right, and we're basically going to treat this time together like a private one -on -one tutoring session.

Because what's really fascinating here is how, well,

how incredibly logical this material becomes when you just step back and look at the big picture.

You definitely don't want to just memorize this stuff in a vacuum.

No, please don't.

Understanding the foundational anatomy directly fuels the specific questions you need to ask in your patient's health history and then, you know, those answers guide your physical exam.

Which ultimately ensures you're providing safe, accurate patient care.

It all connects beautifully once you see the pattern.

It really does.

Okay, so let's unpack this from the very beginning.

We're jumping right into the foundation, which is structure and function.

And to make sense of the plumbing, so to speak, we have to start with the arteries.

The delivery system.

Right.

I always like to think of the arterial system as this high -pressure, heavy -duty delivery network.

Its entire job is taking freshly oxygenated blood from the pumping heart and blasting it out to all the tissues in the body.

Yes.

And because it's dealing with that intense high -pressure right off the heart pump, those artery walls have to be incredibly strong, intense, right?

Exactly.

They are built to handle force.

They have elastic fibers that allow them to stretch with every single heartbeat, which is systole, and then recoil during diastole.

Okay.

But what you really need to care about as a future nurse is the muscle fibers embedded in those walls.

Specifically, what we call the vascular smooth muscle, or VSM.

The VSM.

Right.

The VSM is basically the control center for the amount of blood delivered to the tissues.

Right.

It contracts or dilates to change the diameter of the artery, completely controlling the weight of blood flow based on what the body needs at that exact moment.

And every time the heart beats, it creates a pressure wave, which is the pulse.

Yes.

But you can't just press anywhere on the body to feel it.

You can only really feel it where the artery lies, close to the skin and directly over a bone.

So if I'm doing a head -to -toe assessment,

what are the palpable pulse sites I absolutely need to know?

Let's group them so they're easier to remember.

Starting at the very top in the head and neck, you've got the temporal pulse right in front of the ear and the carotid pulse in the neck.

Got it.

Moving down to the arms, the major artery supplying the arm is the brachial artery, which you'll find at the bend of the elbow.

And just below the elbow, it splits into the ulnar and radial arteries, which run straight down to the wrist.

Right.

And the radial is the classic wrist pulse everyone knows.

But what about the legs?

In the legs, the major supply line is the femoral artery.

That passes right under the inguinal ligament in the groin.

As it travels down the thigh and goes behind the knee, it actually changes its name to the popliteal artery.

Okay.

Popliteal behind the knee.

Then below the knee, it divides again.

In the front, it becomes the dorsalis pedis pulse, which you feel on the top of the foot.

In the back, it's the posterior tibial artery, traveling down behind the medial malleolus.

That's your inner ankle bone.

So that is the delivery network in a totally healthy state.

But what happens when that oxygenated blood can't get to where it needs to go?

That brings us to a critical clinical term, which is ischemia.

Ischemia is simply a deficient supply of oxygenated arterial blood to a tissue.

So a blockage.

Right.

If it's a complete blockage, the tissue starves and dies.

But often, it's a partial blockage.

That creates an insufficient supply that might only actually show up when the tissue needs more oxygen -like when the patient is exercising or walking.

Yeah, this is the absolute hallmark of peripheral artery disease, or PAD, which usually affects the limbs and is most often caused by atherosclerosis or plaque buildup.

Okay.

Make that make sense for me in contrast to the veins.

If arteries are the high -pressure delivery trucks blasting oxygen out, the veins are parallel to them, but the flow is the exact opposite.

Completely opposite.

They're a low -pressure return system carrying carbon dioxide and waste products from the periphery back up to the heart.

And here's a detail that always surprises me.

The body actually has way more veins than arteries, and they lie a lot closer to the surface of the skin.

They do.

But here is the critical physiological problem your body has to solve with veins.

They do not have a pumping heart at their starting line down in your toes to push the blood back up.

So how on earth does blood from your feet defy gravity and get all the way back up to your chest?

I mean, it's not magic.

There has to be a mechanical workaround.

There is, and it relies on three specific mechanisms.

First,

contracting skeletal muscles.

In the legs, this is actually called the calf pump or the peripheral heart.

The peripheral heart?

I like that.

Yeah.

When you walk, your calf muscles contract and literally squeeze the veins physically directing the blood upward.

Second is the pressure gradient caused by your breathing.

How does that work?

When you take a breath in, your thoracic pressure decreases and your abdominal pressure increases.

That pressure shift essentially acts like a vacuum pulling the blood upward.

That's amazing.

And third, veins have intraluminal one -way valves.

These are paired semilunar pockets inside the vein that open to let blood flow toward the heart and then snap shut tightly to prevent gravity from pulling it back down.

That is brilliant engineering.

And because the venous pressure is so much lower than the arterial pressure, the vein walls themselves are thinner and a lot more flexible, right?

Much more flexible.

They have a larger diameter and can actually stretch out to hold more blood when the body's overall blood volume increases.

Precisely.

That's why veins are referred to as capacitance vessels.

This ability to stretch is a vital compensatory mechanism.

By pooling some of that extra blood, it reduces the stress or the preload on the heart.

Which brings us to the third system, which I feel it gets ignored a lot but is so crucial.

The lymphatic system.

If the arteries are the delivery trucks and the veins are the garbage trucks, the lymphatics are a completely separate vacuum system.

A very necessary vacuum system.

They retrieve excess fluid and plasma proteins from the interstitial spaces between your cells and safely return them to the bloodstream.

Why do we even need that though?

To understand why, you have to look at the capillary beds.

Fluid is constantly being pushed out of the capillaries because of the hydrostatic pressure coming from the heart's pumping.

But at the same time, most plasma proteins are too big to leave the blood vessels.

So they stay inside.

Right.

They stay behind in the blood and create what's called colloid osmotic pressure, which acts like a sponge, pulling fluid back into the vessels.

Okay, so you have hydrostatic pressure pushing fluid out and colloid osmotic pressure pulling it back in.

Sounds like a perfect loop.

It would be, but it's not a perfect 50 -50 balance.

A little bit more fluid gets pushed out into the tissues than gets pulled back in.

Without the lymphatic system there to constantly vacuum up that excess fluid, it would rapidly build up in the tissue spaces and produce massive edema or swelling.

Wow.

Okay.

And where does all that vacuumed fluid go?

The lymph vessels converge into two main trunks before dumping back into the venous system.

The right lymphatic duct empties into the right subclavian vein, but it only drains the right side of the head, neck, arm, thorax, lung, and heart.

And the rest of the body.

The thoracic duct does the real heavy lifting.

It drains the entire rest of the body into the left subclavian vein.

So besides fluid control, what else does this system do?

It has three major functions you need to remember for your exams.

First, conserving that fluid and plasma protein we just talked about.

Second, defending the body.

It's a major player in the immune system.

And third, absorbing lipids or fats from the small intestine.

And the lymph nodes play a big part here too.

Absolutely.

There are little oval clumps of tissue that act as filters for the fluid before it returns to the blood.

You'll palpate the cervical nodes in the neck, the axillary nodes in the armpits, the epitrachlear node in the inside of the elbow, and the inguinal nodes in the groin.

You also have related organs aiding this system,

the spleen, the tonsils, and the thymus.

There are also some really important developmental and genetic variations with the lymphatics, right?

Like, if you're assessing a pediatric patient versus an older adult, things look very different.

Completely different.

In children, lymphatic tissue grows incredibly fast.

It's well -developed at birth, reaches adult size by age six, and actually surpasses adult size by puberty.

Wow.

Past adult size.

Yeah.

And then after puberty, it slowly atrophies.

That is totally opposite to aging adults who experience a natural loss of lymphatic tissue over time, leading to fewer and smaller nodes overall.

And if we connect this foundational anatomy to the bigger picture of clinical practice, genetics play a huge role too, particularly with peripheral artery disease.

Yes.

Research has identified specific PAD gene loci.

What's fascinating is that variants at these genetic locations strongly suggest that smoking and thrombosis play a much greater role in PAD than they do in other arterial diseases.

Which is exactly why asking about a patient's smoking history is so critical.

Exactly.

We also know there are significant documented health disparities here.

Black Americans, women, and aging adults are disproportionately affected and require comprehensive screening for PA.

The first line non -invasive test you'll use for that is the ankle brachial index, or ABI, which we'll break down in a few minutes.

Awesome.

So how does all this anatomy translate into the real world when you walk into a patient's room?

Because we understand that arteries deliver, veins return, and lymphatics vacuum, we now know exactly what subjective data we need to collect on our clipboards.

The health history interview.

Exactly.

It's broken down into six key areas.

Let's walk through them organically.

Where do we start?

You start with the most common complaint, leg pain or cramps.

But you have to dig deeper.

You need to ask about their claudication distance.

Claudication distance?

That simply means asking exactly how many blocks or stairs can you walk before the pain forces you to stop.

Okay, but what if they say it hurts when they aren't even walking?

What if the pain wakes them up at night?

That is a massive red flag.

Night leg pain in aging adults can indicate ischemic rest pain.

Think about gravity.

When they are standing, gravity helps push that arterial blood down to the feet.

When they lie flat in bed, they lose that gravitational assist.

So the severe PAD means the tissues suddenly aren't getting enough oxygen.

Exactly.

Causing intense pain.

That makes so much sense.

Okay, after pain, what's the next big clue?

Skin changes.

Are their arms or legs cool to the touch?

Coolness occurs with PAD because the warm blood isn't reaching the skin.

You also want to ask if they have bulging crooked varicose veins or if they have any leg sores or ulcers that just won't heal.

Next up is swelling or edema.

Obviously, you ask what time of day it's worse and what makes it better.

But the really crucial question here is whether the swelling is bilateral, meaning both legs, or unilateral, meaning just one leg.

Why is that distinction so important?

Because it completely changes your diagnosis.

Bilateral swelling points to a systemic whole body issue like heart failure.

The heart is struggling to pump so fluid backs up everywhere.

And unilateral.

Unilateral swelling points to a local problem.

If only one leg is huge, there is a local obstruction in that specific leg, like a deep vein thrombosis or DVT.

Got it.

The fourth area is lymph node enlargement.

You just ask if they've noticed any swollen glands and if they feel hard or soft or if they hurt.

Enlarged nodes can signal anything from a mild infection to a malignancy.

What about the fifth area, medications?

Are there specific meds that affect the vascular system?

Absolutely.

You specifically want to ask if they are taking oral contraceptives or hormone replacement therapy.

Those medications can cause a hypercoagulable state, significantly increasing their risk of forming dangerous blood clots.

You also want to check if they take a daily low -dose aspirin, which many people use to prevent clots.

And the final piece of the subjective interview.

Smoking history.

As we mentioned earlier, tobacco constricts arteries, increases the coagulability of the blood, injures the inner lining of the vessels, and promotes inflammation.

It is the absolute strongest risk factor for PD.

It really is.

In fact, if a patient started smoking at age 16 or younger, it more than doubles their future risk of developing PD.

Exactly.

So now you have their history.

It's time to gather your objective data with the physical exam.

To set the scene for a good vascular exam, your environment matters.

The room temperature should be about 72 degrees Fahrenheit or 22 degrees Celsius and draftless.

If the room is freezing, the patient's vessels will vasoconstrict.

If it's too hot, they vasodilate.

Either way, it skews your findings.

And you have to remember the golden rule of physical assessment here.

Always compare sides bilaterally.

Always.

You can't know what's abnormal for a patient if you don't know what their normal looks like on the other side.

Let's start with the sequence for examining the arms.

You always begin with inspection.

Lift both their hands, note the color of the skin and the nail beds, and check the profile of their fingers to see if there is any clubbing.

For reference, the normal nail bed angle is 160 degrees.

Then you move to capillary refill.

You depress the patient's nail bed until it blanches white.

Then you let go and count how long it takes for the pink color to return.

It should take less than one to two seconds.

If it takes longer, what does that delayed refill actually tell us?

Capillary refill is a direct index of peripheral perfusion and cardiac output.

A delayed refill signifies that the vessels are vasoconstricted, or that the heart simply isn't pumping out enough blood volume to reach the fingertips quickly.

And after that, you palpate.

Right.

You'll check the radial pulse on the thumb side of the wrist and the ulnar pulse on the pinky side.

Though it's worth noting the ulnar is often not palpable in totally healthy people, so don't panic if you can't find it.

Good to know.

You also check the brachial pulse in the elbow.

You grade the force of these pulses on a standard three -point scale.

Finally, you check the apatrachlear lymph node.

You do this by essentially shaking hands with the patient and reaching your other hand under their elbow to feel the groove between the biceps and priceps.

Normally, this node is not palpable.

Okay, here's where the physical exam gets critical for patient safety.

We need to talk about the modified Allen test.

As a nurse, you may find yourself needing to cannulate the radial artery, meaning you have to place an arterial line in the wrist.

But before you ever insert that needle, you have to do this test.

Why?

Because if that radial artery gets damaged or clotted off by your catheter, the hand loses its main blood supply.

You have to prove that the hand has adequate collateral blood supply through the ulnar artery to keep the hand alive, just in case.

That is terrifying, but so important.

So how do I actually perform the Allen test?

I've read the steps, but walk me through the visual.

I'm literally cutting off all blood to their hand for a second, right?

Yes, temporarily.

Here are the exact steps.

First,

firmly occlude or press down hard on both the ulnar and radial arteries of one hand at the same time.

While you do that, the person makes a tight fist several times.

This squeezes the blood out, causing the hand to blanch, turning pale.

Second, ask the person to open their hand, but tell them not to hyperextend their fingers.

Just relax them.

And then the third step.

Third, and this is the key, release the pressure on the ulnar artery only, while keeping your thumb pressed down hard on the radial artery.

So I'm watching to see if the ulnar artery alone can refill the hand.

Exactly.

You are looking for a palmar blush.

The normal pink color should return to the hand in less than seven seconds.

That proves the ulnar artery is open and functioning.

If the hand stays pale, you absolutely cannot cannulate that radial artery.

Wow, okay.

Moving down to the legs.

The exam sequence is very similar.

You start with inspection, note the skin color, the hair distribution.

By the way, even on shaved legs, it's normal to find hair on the toes, check the venous pattern and look for symmetry.

Yes.

And if the legs look distinctly asymmetric, or if you suspect a deep vein thrombosis based on their history, you have to measure the calf circumference.

Right.

You use a non -stretch tape measure and you measure at the widest point of the calf, ensuring you are exactly the same distance down from the patella or kneecap on both legs.

An asymmetry of two centimeters or more is a strong indicator of a DVT.

Next is palpation.

You feel the temperature of the legs using the back of your hand.

If you feel a unilateral cool foot, or if there is a sudden temperature drop as you move your hand down the leg, that is a huge red flag for arterial ischemia.

The warm blood is hitting a roadblock.

Then you palpate the inguinal nodes in the groin and locate the leg pulses.

You have the femoral pulse just below the inguinal ligament.

If it feels weak, grab your stethoscope and listen over it for a brute, which is a swooshing sound indicating turbulent blood flow.

And then check the popliteal pulse behind the knee.

Right.

The popliteal, the dorsalis pedis on the top of the foot, and the posterior tibial inside the ankle.

Next, you check for pre -tibial edema by firmly depressing the skin over the tibia bone for five seconds and releasing.

I always get the grading scale for edema mixed up.

If pitting edema is present, meaning my thumb leaves an indent, I have to grade it from one plus to four plus.

What does a four plus actually look like in practice compared to a one plus?

A one plus is very mild pitting.

It leaves a slight indentation, but the leg doesn't look perceptibly swollen to the eye.

A four plus, on the other hand, is very deep pitting.

Your thumb leaves an indentation that lasts a long time, and the leg looks grossly swollen and distorted.

It's a very obvious difference clinically.

Finally, for the legs, you do a neurologic check.

For patients with a history of diabetes, PAD, or HIV, you must test for sensation on the sole of the foot using a monofilament tool.

Sensory loss is a major dangerous complication of arterial deficit.

Before we wrap up the objective data, let's break down those two crucial evidence -based clinical tools the text provides.

The first is the ABI, or ankle brachial index.

You calculate this by taking the highest ankle systolic pressure and dividing it by the highest arm systolic pressure.

A normal ABI is between 1 .0 and 1 .4.

If the number is 0 .90 or less, that specifically indicates peripheral artery disease.

Wait, so if the number is too high, like above 1 .4, is that a good thing?

Does that mean super strong blood flow?

Actually, no.

It's a bad sign.

If the ABI is greater than 1 .4, it suggests the arteries are heavily calcified and essentially turned to stone.

Oh, wow.

Yeah.

They are non -compressible, which frequently happens in people with long -standing diabetes or chronic kidney disease.

The pressure cuff can't squeeze them shut, so it gives a falsely high reading.

Good to know.

And the second tool.

The Wells Criteria.

This is a simple scoring system used to determine the probability of a DVT.

A score of one or two means moderate probability, while a score of three points or more indicates a high probability of a DVT.

So we've gathered all this data.

Let's shift to Section 4, Health Promotion, Documentation, and Abnormal Findings.

How do we empower the patient with this knowledge?

The text provides excellent practical guidelines for diabetic and PAD foot care.

Patient education is vital here.

You need to teach your patients to physically inspect their feet every single day, using a mirror if they can't see the bottoms.

They should wash them with mild soap and warm water, but they need to avoid adding oil to or bubble pads that make the tub slippery and risk a fall.

Makes sense.

They should use a mild skin lotion to prevent cracking, but never put lotion between the toes as that promotes fungal infections.

And of course, they need to wear comfortable, well -fitting shoes at all times.

And as a nurse, you have to document all of this assessment accurately.

What does a pristine normal chart entry look like?

For the subjective portion, you would write, no leg pain, no skin changes, no swelling or lymph node enlargement, no history of heart or vascular problems, diabetes or obesity, does not smoke.

On no medication.

And the objective.

For the objective portion, you document,

extremities have color appropriate for race or ethnicity,

capillary refill less than two seconds, pulses two plus and equal bilaterally.

But of course, you are reading this chapter to learn how to catch when things go wrong.

Let's look at the abnormal findings you need to memorize.

What are the biggest red flags?

Let's start with pulse variations.

One unique pulse to note is pulses spasferians.

This is a specific finding where each pulse actually has two strong systolic peaks with a little dip in between them.

It is highly associated with aortic valve stenosis.

Okay, what else?

Another classic presentation is Renault Phenomenon, which affects the hands.

Raynaud's is the one with the tricolor change, right?

Yes.

It features abrupt progressive color changes of the fingers in response to cold temperatures, vibration, or even emotional stress.

First, the fingers go stark white due to a sympathetic mediated vasospasm, which cuts off the arterial supply.

Then they turn blue.

Right, they turn blue, or cyanotic, due to a slow trickle of blood where the oxygen is heavily extracted by the starving tissues.

Finally, they turn bright red, or ruber, due to reactive hypersemia as the spasm relaxes and blood violently rushes back into the dilated capillary beds.

The ultimate cheat sheet you need for this chapter, though, is the distinction between arterial disease and venous disease.

They are polar opposites.

Exactly.

Let's contrast them.

Chronic arterial symptoms involve deep muscle pain, usually in the calf, brought on by specific distances of walking.

That's claudication.

The skin will be cool and pale, and remember gravity.

The pain gets worse if you elevate the leg, because now you are making that already weak arterial flow fight gravity to get to the toes.

And acute arterial symptoms.

Acute arterial symptoms are a limb -threatening emergency.

You are looking for the six PAs pain, pallor, which is paleness, pulselessness, paresthivia, which is a tingling sensation, poikilothermia, which means coldness and paralysis.

On the other hand, you have venous disease.

Chronic venous symptoms present as an aching heavy fullness in the calf or lower leg that gets worse at the end of the day, or with prolonged standing.

Elevation actually relieves this pain, because gravity is finally helping the veins drain that pooled blood back to the heart.

You'll see edema, varicosities, and weeping wet ulcers at the ankles.

And acute venous.

Acute venous symptoms, like a DVT, present very differently.

It's a sudden, intense, sharp, deep muscle pain with a warm, red, and intensely swollen leg.

It is genuinely so satisfying to see how this all ties together.

The incredible logic of this chapter, from understanding the high pressure arteries pushing oxygen out, to the low pressure veins and their calf pumps struggling to bring waste back, to the lymphatic vacuum cleaning up the interstitial mess.

It really is a beautiful system.

That underlying anatomy tells you exactly why you ask about smoking and walking distances in your health history.

It tells you exactly why you check pulses, capillary refill, and edema in your physical exam.

And it gives you the knowledge to instantly interpret what is perfectly normal versus a tissue -threatening emergency.

You've got this.

The volume of information in nursing school can feel incredibly overwhelming.

But mastering these foundational concepts is exactly what builds a safe, exceptional, and deeply competent nurse.

Keep connecting the dots and trust the process.

On behalf of the Last Minute Lecture team, thank you so much for letting us help you study today.

I'm going to leave you with a final, fascinating mechanical visual, directly from the text to mull over.

The next time you take a deep breath, I want you to close your eyes and picture the invisible pressure gradient you just created inside your own body.

By simply expanding your lungs, you lowered the pressure in your chest and raised it in your abdomen.

In doing so, you are literally sucking the venous blood all the way from your big toe, up your leg, through your abdomen, and safely back into your heart.

It is a built -in vacuum pump powered entirely by your breath, keeping you alive every single minute.

See you next time.