A&P of Skin: Characteristics of Normal Skin, Structures and Function, Maintenance of Healthy Skin
Skin and Wound Care. Produced by the Emory Nursing Wound Ostomy Continence Nursing Education Center.
Transcript
Hello and welcome to the Skin and Wound Care course.
Dorothy Doty:My name is Dorothy Doty.
Dorothy Doty:I'll be your instructor for this course.
Dorothy Doty:We're going to start with anatomy and physiology of the skin across the lifespan.
Dorothy Doty:So here are your objectives.
Dorothy Doty:You want to, at the end of this class, be able to describe the layers of the skin and the soft tissue in terms of the key structures and functions.
Dorothy Doty:You want to be able to describe changes in the skin across the lifespan and especially to know the implications for nursing management.
Dorothy Doty:You should be able to differentiate between the skin and tissue layers that are capable of regeneration and those that are not.
Dorothy Doty:And we will emphasize that because it's important in terms of wound healing.
Dorothy Doty:You should be able to describe the characteristics of healthy skin and the implications for routine skin care.
Dorothy Doty:And finally, you should be able to utilize correct dermatologic terminology when you're describing skin lesions and wounds.
Dorothy Doty:Now, you're going to view this lesson, you're going to complete the online self study learning exercises, and you should read chapter one in the core curriculum if you need additional information.
Dorothy Doty:Now, we have divided this first class into two sections.
Dorothy Doty:So you're going to see the overview for part one and then the summary for part one, then the overview and the summary for part two.
Dorothy Doty:If you want to take a break, you can.
Dorothy Doty:If you want to keep moving through, you can do that as well.
Dorothy Doty:So in part one, we're going to discuss the characteristics of normal skin.
Dorothy Doty:We're going to talk about the skin and soft tissue layers, specifically the epidermis, the dermis, the subcutaneous tissue and the muscle.
Dorothy Doty:And we're going to talk about strategies to keep the skin healthy.
Dorothy Doty:So let's talk about the skin in kind of big picture terms.
Dorothy Doty:First of all, it's the largest organ system in the body.
Dorothy Doty:It's 21 square feet.
Dorothy Doty:So we kind of know this, but we really don't think of the skin most of the time as being such an important organ system.
Dorothy Doty:When you talk to nurses, we tend to focus on the cardiovascular system, the pulmonary system, the renal system, the neurologic system, and the skin kind of fades into the background unless there's a major problem.
Dorothy Doty:But for those of you who have taken care of burn patients, those of you who have taken care of patients with necrotizing fasciitis, with cutaneous T cell lymphoma, or any other condition that causes massive skin loss, you recognize that the skin is actually critical to health and to survival because it plays the critical role of separating the internal environment and the external environment.
Dorothy Doty:When you think about burn patients, what do we worry about?
Dorothy Doty:Well, we worry in the early days about fluid and electrolyte imbalance because they're losing copious amounts of fluids from the internal environment throughout the length of the burn until we get closure.
Dorothy Doty:We worry about infection because they've lost that barrier.
Dorothy Doty:So when you think of the skin, you think of it as creating that barrier, that dividing line between the internal environment and the external environment.
Dorothy Doty:You think of it as holding in critical fluids and keeping out dangerous pathogens and irritants.
Dorothy Doty:So we obviously want to keep the skin healthy.
Dorothy Doty:Now, what are the characteristics of healthy skin?
Dorothy Doty:When you're providing skin care, you should always be using products and protocols that help to keep the skin dry, but supple and acidic.
Dorothy Doty:So let's talk about each one of those.
Dorothy Doty:When we talk about keeping the skin dry, we don't mean dry as in cracking and flaking.
Dorothy Doty:We mean dry as in not wet.
Dorothy Doty:You know that macerated skin is vulnerable skin, because when the skin is macerated, it means that the cells are over hydrated, over hydrated cells are stretched, the cell membrane is stretched.
Dorothy Doty:That macerated skin becomes extremely vulnerable to minor mechanical trauma and to pathogenic invasion.
Dorothy Doty:So we want it dry as in not wet, but we want it supple, we want it soft and able to withstand minor frictional forces.
Dorothy Doty:We'll talk more about that.
Dorothy Doty:And we want to maintain an acidic ph.
Dorothy Doty:So the ph of normal skin ranges somewhere between about 4 and 6.8.
Dorothy Doty:Once the skin becomes alkaline in ph, it's much more vulnerable.
Dorothy Doty:So you probably remember hearing about the acid mantle of the skin.
Dorothy Doty:What they mean by that is that the acidity that is characteristic of healthy skin actually helps to reduce bacterial proliferation, reduce the risk of skin infection.
Dorothy Doty:Also, you want to think of the skin as having a brick and mortar configuration.
Dorothy Doty:So if you look at the little brick wall on your slide, it's there for a reason.
Dorothy Doty:So we want you to think of the skin cells as bricks, and we want you to think of the skin oils as the mortar.
Dorothy Doty:And when you think about a brick wall, you think how critically important the mortar is to the integrity of the brick wall.
Dorothy Doty:Yes, bricks are impervious to rain, to almost everything, but if you don't fill the gaps between those bricks, the brick wall falls down.
Dorothy Doty:When it comes to the skin, the skin cells are the bricks.
Dorothy Doty:Now, we've already talked about the fact that if the skin becomes overhydrated, macerated, the cells swell and become very vulnerable.
Dorothy Doty:What happens if the skin cells become dehydrated?
Dorothy Doty:If you have a dry skin environment, well, then the skin cells shrink and that creates gaps between the skin cells and the mortar.
Dorothy Doty:So our goal is to keep the skin appropriately moisturized to maintain the lipids between the cells and to maintain a healthy brick wall that keeps out pathogens and keeps fluid in.
Dorothy Doty:Now look at the diagram on the top of your slide that shows lipids in the skin, specifically ceramides.
Dorothy Doty:Ceramides are the most common skin oil in healthy skin.
Dorothy Doty:You see a very high concentration of skin lipids and the ceramides, the lipids fill the gaps between the cells, maintain that barrier function.
Dorothy Doty:Now go to the right on that top diagram and you see that in pathologic conditions, the level of skin lipids is markedly reduced.
Dorothy Doty:And what does that tell you?
Dorothy Doty:It means that you have thinned out mortar, you have multiple gaps in your barrier function, and it's very easy for pathogens and irritants to penetrate.
Dorothy Doty:So critical to maintain normal mortar, which translates into replace lost lipids.
Dorothy Doty:And we'll keep coming back to that.
Dorothy Doty:Now in your reading and when you go to conferences, you're going to hear the term tewl, or some researchers refer to it as tool.
Dorothy Doty:That stands for transepidermal water loss, and it's actually a measure of skin health.
Dorothy Doty:When you have an intact barrier, there's very low levels of transepidermal water loss because the moisture is retained as the barrier function is lost.
Dorothy Doty:As the skin is damaged, your transepidermal water loss levels go up.
Dorothy Doty:So I just want you to know what that means.
Dorothy Doty:You don't have to memorize anything specific in terms of numbers.
Dorothy Doty:Just recognize that transepidermal water loss is an indicator of skin health.
Dorothy Doty:And finally, I want you to remember that the normal thickness of the skin, including the epidermis and the dermis, is about 2 millimeters.
Dorothy Doty:So it's pretty thin.
Dorothy Doty:That actually can be helpful when it comes to pressure injury staging, which we'll get to later in this course.
Dorothy Doty:Okay, so now let's start breaking it down.
Dorothy Doty:We've looked big picture at the characteristics of the skin, what it does for us, what we should be doing to keep the skin healthy.
Dorothy Doty:Now let's look at each of the structures.
Dorothy Doty:Let's look at epidermis, let's look at dermis, and then let's look at soft tissue, sub Q and muscle.
Dorothy Doty:The epidermis, of course, is the outer layer of the skin.
Dorothy Doty:It includes four to five sub layers.
Dorothy Doty:We're going to discuss each one of those.
Dorothy Doty:And in a healthy adult, the epidermis is about 20 cell layers thick.
Dorothy Doty:So let's break those sub layers down.
Dorothy Doty:The top layer, the stratum corneum, is composed essentially of dry, sloughing keratinocytes.
Dorothy Doty:So this layer upon which we lavish so much attention, where we put our moisturizers, et cetera, that's a layer of dead cells.
Dorothy Doty:Now, the good news is the moisturizers do penetrate into deeper layers and help to maintain that mortar balance and to fill the gaps between cells.
Dorothy Doty:But the top layer is sloughing cells, and you know that.
Dorothy Doty:You know that those dead epidermal cells essentially act as shingles.
Dorothy Doty:So you think about the roof of the house, and you think about the overlapping shingles and how in an intact roof, the shingles keep everything out, okay?
Dorothy Doty:So they protect the house against rain, excessive wind, etc.
Dorothy Doty:That's what the stratum corneum does for you.
Dorothy Doty:So it's several cell layers thick, and all of those cell layers are dead dry and in the process of sloughing off.
Dorothy Doty:But in their time on the surface of the skin, those dead keratinocytes act as your shingles, keeping moisture in and keeping pathogens out.
Dorothy Doty:The next layer, the stratum lucidum, is not always present.
Dorothy Doty:It's only present in the palms of the hands and the soles of the foot.
Dorothy Doty:And it just gives extra protection to areas that are exposed to constant friction.
Dorothy Doty:The third layer down, the stratum, granulosum, is several cell layers thick.
Dorothy Doty:It's a very important layer because this is where the ceramides are produced.
Dorothy Doty:So ceramides are the skin oils.
Dorothy Doty:They are produced by the keratinocytes.
Dorothy Doty:They're stored in little organelles known as odland bodies.
Dorothy Doty:And at the level of the stratum granulosum, they're released into the extracellular tissue where they attract moisture, help to maintain normal water balance in the skin.
Dorothy Doty:You don't have to remember this number, but it's interesting to note that normally the skin is 10 to 15% water.
Dorothy Doty:You don't want it more than that, and you don't want it less than that.
Dorothy Doty:So that's the good zone, 10 to 15%.
Dorothy Doty:The fourth layer is the stratum spinosum.
Dorothy Doty:And the critical aspect of this layer, this is where you have desmosomes.
Dorothy Doty:And what does that mean?
Dorothy Doty:Well, desmosomes actually are molecules that attach the cells to each other so that it provides structural integrity to the skin and reduces the risk of frictional trauma causing skin disruption.
Dorothy Doty:So the desmosomes play an important role.
Dorothy Doty:And finally, the basement layer is the stratum germinativum.
Dorothy Doty:This is a single layer of dividing cells.
Dorothy Doty:So what you want to think of is these little keratinocytes start out at the stratum germinativum, where they're reproduced or they are produced, and then they start to migrate upward.
Dorothy Doty:Okay, so think of the stratum germinativum as the basement.
Dorothy Doty:So they're produced in the basement, they start to migrate upward, migrate upward.
Dorothy Doty:As they migrate, they carry out some functions.
Dorothy Doty:They produce ceramides, release the ceramides, they gradually lose their nucleus and become filled with keratin, so that by the time they reach the roof, they're very well prepared to serve as a shingle.
Dorothy Doty:Now, the key cells and structures in the epidermis, the keratinocytes, of course, also known as epidermal cells.
Dorothy Doty:So we think of them as epidermal cells.
Dorothy Doty:They can also be called keratinocytes because as they migrate, they become filled with keratin, which is that waterproof substance that makes them very effective shingles.
Dorothy Doty:So epidermal cells, keratinocytes, basically the same thing.
Dorothy Doty:You also have melanocytes.
Dorothy Doty:And, you know, melanocytes give each of us our unique skin color.
Dorothy Doty:The more melanin you have in the skin, the more protection you have against radiation and against sun damage.
Dorothy Doty:So you see that in climates where it's very hot much of the year, where there's a lot of sun exposure, the skin is more darkly pigmented.
Dorothy Doty:In areas where there's very little skin or sun exposure, then you have very light skinned individuals.
Dorothy Doty:So melanocytes play an important role in protecting individuals based on where they live.
Dorothy Doty:In the epidermis, you also have nerve receptors.
Dorothy Doty:So those are the little receptors that recognize temperature, recognize pressure, recognize pain, recognize irritants that cause itching.
Dorothy Doty:Do you think how sensitive your skin is?
Dorothy Doty:You're aware of even breezes blowing against your skin, you're aware of light touch.
Dorothy Doty:The epidermis is acutely sensitive to any kind of painful stimulus, Acutely sensitive to extremes of temperature.
Dorothy Doty:So extreme cold, extreme heat.
Dorothy Doty:And the number of receptors is reflected in the fact that if you touch something hot, you pull your finger away before your brain even registers that it was hot.
Dorothy Doty:It's a reflex that protects you.
Dorothy Doty:So a lot of nerve receptors in the epidermis that communicate to nerve cells in the dermis, also in the epidermis, you have langerhan cells.
Dorothy Doty:They're part of your skin immune system.
Dorothy Doty:They actually recognize and present antigens to the CD4 cells.
Dorothy Doty:So they're Kind of roaming around looking for troublemakers.
Dorothy Doty:When they find one, they attach to it.
Dorothy Doty:So they essentially drag it along, take it over to the CD4 cell and say, look what I found.
Dorothy Doty:And then the CD4 cells take it from there.
Dorothy Doty:Critical functions of the epidermis.
Dorothy Doty:We've already said the major function, as you see on the third bullet point, is protection.
Dorothy Doty:The epidermis does serve that barrier function between the external and internal environment.
Dorothy Doty:Critical things to recognize.
Dorothy Doty:There are no blood vessels in the epidermis.
Dorothy Doty:So when you think about it, when you get a blister, you just leak clear fluid.
Dorothy Doty:If you get a little skin tear, they just leak clear fluid.
Dorothy Doty:Because there are no blood vessels in the epidermis.
Dorothy Doty:You don't need blood vessels because you only have one layer of living, reproducing cells, and that layer is sitting right next to the dermis where there are many blood vessels, so no blood vessels.
Dorothy Doty:Another critical structure in the epidermis are the rate ridges, also sometimes called rate pegs.
Dorothy Doty:So when you look at the diagrams of the skin and you look at the junction between the epidermis and the dermis, you'll see they always show the epidermis as having these little pegs or ridges that dip down and interlock with the dermal papillae.
Dorothy Doty:So you get this kind of interlocking configuration that gives the skin a lot of its structural stability.
Dorothy Doty:When you go to start an IV on someone, normally you can put traction on the epidermis while you locate the vein, insert the angiocath, and when you let go, the epidermis and dermis move back into position.
Dorothy Doty:They move as one layer.
Dorothy Doty:That's because of that interlocking configuration, very important to skin integrity.
Dorothy Doty:We'll talk a little bit more later on about the fact that early in life and late in life, you have less of that interlocking configuration, which explains why infants and the elderly are much higher risk for skin tears.
Dorothy Doty:Now, let's come down.
Dorothy Doty:We're going to look now at the junction between the epidermis and the dermis.
Dorothy Doty:This is known as the epidermal dermal junction, is also known as the basement membrane zone.
Dorothy Doty:And we've already talked about how important this interlocking configuration is, how it provides structural stability to the skin.
Dorothy Doty:If you have problems with a blistering skin condition, like bullous pemphigoid or epidermolysis bullosa, it typically attacks structures at the basement membrane zone, at the dermal epidermal junction and breaks down that interlocking configuration and allows the layers to move independently.
Dorothy Doty:So what does the basement membrane zone do?
Dorothy Doty:It anchors the epidermis to the dermis.
Dorothy Doty:Now let's move into the dermal layer.
Dorothy Doty:That's the inner layer of the skin.
Dorothy Doty:It's the much thicker layer of the skin, because, remember, the epidermis, even in a healthy adult, is only 15 to 20 cell layers thick.
Dorothy Doty:Very, very thin.
Dorothy Doty:So it's the dermis that adds thickness and a lot of the structural strength to the skin.
Dorothy Doty:Now, they divide the dermis into the papillary dermis and the reticular dermis.
Dorothy Doty:Why?
Dorothy Doty:Well, simply because of some differences in structure.
Dorothy Doty:So the papillary dermis is the part that interfaces and interlocks with the epidermis.
Dorothy Doty:And you have these dermal papillae that project upwards and then the epidermal ridges that project down.
Dorothy Doty:Now, those little dermal papillae, they contain a lot of capillary loops that nourish that basement membrane layer of the epidermis.
Dorothy Doty:So it's a very important configuration.
Dorothy Doty:Not only does it provide structural integrity and strength, but it also provides critical nutrients to the reproducing layer of the epidermis.
Dorothy Doty:Now, those papillary loops extend up like this, but they're supported by a horizontally oriented layer of blood vessels.
Dorothy Doty:Why is that important?
Dorothy Doty:If the vessels are oriented horizontally, they are much more subject to point pressure.
Dorothy Doty:So you think about, say, stage two pressure injuries.
Dorothy Doty:It's like, well, how do you get a stage two pressure injury?
Dorothy Doty:Well, in part because the skin itself is nourished primarily by vessels that are oriented horizontally.
Dorothy Doty:So point pressure, like you get with a medical device, can occlude those horizontally oriented vessels and cause localized ischemia.
Dorothy Doty:So just be aware of that then.
Dorothy Doty:The reticular dermis is the deeper component of the dermis.
Dorothy Doty:That's where you have your extensive network of blood vessels.
Dorothy Doty:That's where you have your lymphatics.
Dorothy Doty:That's where you have a lot of collagen and elastin.
Dorothy Doty:The type of collagen in the dermis is primarily type 1 collagen.
Dorothy Doty:That will be important when we talk about wound healing.
Dorothy Doty:So in the dermis, primarily type 1 collagen.
Dorothy Doty:Now, if anybody ever asked you, do you think this wound extends into the reticular dermis, or do you think it stops at the papillary dermis?
Dorothy Doty:There's no way to tell.
Dorothy Doty:So just pick one and stick with your initial statement.
Dorothy Doty:What are the key cells in the dermis?
Dorothy Doty:Fibroblast and macrophages are the two most important types of cells in the dermis.
Dorothy Doty:Fibroblasts, as you know, are the only cells in the body that can synthesize collagen and elastin, which are the two connective tissue proteins most prominent in the dermis.
Dorothy Doty:So, of course, you would have fibroblasts present in the dermis to provide collagen repair, to provide elastin repair for any minor damage.
Dorothy Doty:Also in the dermis, you have large numbers of macrophages.
Dorothy Doty:And macrophages are white blood cells derived from the monocytes, and they provide protection.
Dorothy Doty:So they're roaming around.
Dorothy Doty:They can identify any bacteria, any fungal organisms, and they can phagocytize those organisms to prevent infection from occurring.
Dorothy Doty:So macrophage is critical to maintaining skin health and preventing skin infection.
Dorothy Doty:Super critical when you have an open wound, in preventing wound infection.
Dorothy Doty:Also in the dermis, you have mast cells.
Dorothy Doty:Mast cells produce histamine in response to allergens or irritants.
Dorothy Doty:So they are the architects of the inflammatory response.
Dorothy Doty:The inflammatory response is part of your skin immune system because it causes vasodilation.
Dorothy Doty:That's what histamine does.
Dorothy Doty:It causes vasodilation, which brings more white blood cells to the area to take on whatever problem has occurred.
Dorothy Doty:A very important set of structures that are anatomically located in the dermis are the hair follicles, the sebaceous glands, and the sweat glands.
Dorothy Doty:These structures are known as epidermal appendages, even though, as you can see from the diagram, they're located anatomically deep in the dermis at the very base of the dermis.
Dorothy Doty:So why are they called epidermal appendages?
Dorothy Doty:Well, if you look carefully at the slide, you'll see that these structures are lined with the basement membrane of the epidermis.
Dorothy Doty:So it's almost like they were sitting in the epidermis and fell down to the base of the dermis and took that basement membrane layer with them.
Dorothy Doty:Now, why is it important for us to talk about these separately?
Dorothy Doty:It's important because when we get to wound healing, there are two ways in which wounds heal.
Dorothy Doty:One is by replacing lost structures with more of the same.
Dorothy Doty:And the other is by scar tissue formation.
Dorothy Doty:So it's critical to know which structures in the skin and the soft tissue can reproduce and which ones cannot.
Dorothy Doty:So look at bullet point 2.
Dorothy Doty:Almost everything in the dermis can reproduce.
Dorothy Doty:You can make more collagen, you can make more elastin, you can make more blood vessels.
Dorothy Doty:You can make more of everything in the dermis, except you cannot make more hair follicles, you cannot make more sebaceous glands, you cannot make more sweat glands.
Dorothy Doty:And you kind of know this because you know in taking care of a burn patient that if that burn extends to the deep dermis or beyond, that patient will never have hair in that area again, will never have oil production, will never have sweat production in that area again.
Dorothy Doty:Same thing when you have an incision.
Dorothy Doty:So you don't get hair growth in an incision because it goes all the way through the skin into deeper structures.
Dorothy Doty:So the bottom line is, once you eliminate hair follicles, they don't come back.
Dorothy Doty:Once you eliminate sebaceous glands, they don't come back.
Dorothy Doty:Once you eliminate sweat glands, they don't come back.
Dorothy Doty:When you talk about wounds that can heal by regeneration, replacing loss structures with more of the same, it's wounds that are limited to the epidermis and the upper dermis.
Dorothy Doty:Any wound that extends to the deep dermis that causes destruction of the epidermal appendages, those will not be replaced.
Dorothy Doty:Instead, they'll be.
Dorothy Doty:There will be substitution with scar tissue.
Dorothy Doty:So we'll keep coming back to that.
Dorothy Doty:It's an important concept.
Dorothy Doty:Okay, so we've gone through this skin, the epidermis, and the dermis, and now we're down to the subcutaneous tissue, the hypodermis, also known as the fat, which actually is a critical tissue layer that does not get credit for the important roles it plays.
Dorothy Doty:You never hear somebody say, you know, I pretty much like my fat.
Dorothy Doty:I think I've got just about the right amount.
Dorothy Doty:I like the way it covers my bony prominences and protects me.
Dorothy Doty:But we should say that, because when you think of patients like you see in this slide, what do you think you see?
Dorothy Doty:Someone who is acutely vulnerable to pressure, to shear, because there is no padding.
Dorothy Doty:So the subcutaneous tissue plays the critical role of providing padding and even pressure distribution.
Dorothy Doty:What are the key components of fat?
Dorothy Doty:Well, obviously the fat itself, the adipose tissue, some connective tissue, some blood vessels, though not that many, some lymphatics and some nerve cells.
Dorothy Doty:A couple of critical things to think about in relation to the fat.
Dorothy Doty:We've already talked about how critically important it is in providing prot against pressure and shear.
Dorothy Doty:I'm betting that a lot of you have noticed that your very thin patients are much higher risk than your heavy patients.
Dorothy Doty:So when you have a patient who comes in with essentially no sub q tissue, you know, you have to provide extremely high level protection if you're going to keep them from experiencing skin breakdown.
Dorothy Doty:The lady in the slide gave My permission gave me permission to use her photo in an educational presentation.
Dorothy Doty:You will see she has no fat and essentially has lost all of her muscle.
Dorothy Doty:She did not have breakdown because she retained normal sensation and she retained mobility.
Dorothy Doty:But if you took that same patient and you took her to surgery and she was in surgery for 8 to 10 hours and then impact you for 2 to 4 hours hours, and then in critical care, how long would it take before she developed significant pressure injuries?
Dorothy Doty:Not long at all.
Dorothy Doty:So she's extremely vulnerable.
Dorothy Doty:The other thing to know about subcutaneous tissue, and I know you kind of don't believe this, but it does not regenerate.
Dorothy Doty:You do not make more fat.
Dorothy Doty:You're like, yes, I do.
Dorothy Doty:I make it at night when I'm asleep and not paying attention.
Dorothy Doty:Here's what happens.
Dorothy Doty:We basically make all of our fat cells when we're kindergarten age.
Dorothy Doty:So as young children, we make all of our fat cells.
Dorothy Doty:Now, fat cells are like bank accounts.
Dorothy Doty:You can add to those fat cells and they stretch and you get increasing sub Q mass.
Dorothy Doty:Or you can withdraw fat and they shrink and you sub Q mass goes down, but you don't make more.
Dorothy Doty:That's why liposuction works, because once you suck out fat cells, they're gone.
Dorothy Doty:And then if you keep eating a lot, of course, you just deposit in other fat cells.
Dorothy Doty:So critically important to recognize two things about fat.
Dorothy Doty:It plays an important role in protection and it is not reproduced.
Dorothy Doty:What about the muscle layer?
Dorothy Doty:So you come down, you've got skin, fat, muscle.
Dorothy Doty:The muscle layer sits right next to the bone, and the muscle layer, out of all of the tissue layers has the highest metabolic rate.
Dorothy Doty:Because when you think about it, the muscle is always working as opposed to the skin and the fat.
Dorothy Doty:The skin and the fat play kind of a passive role, but the muscle every day plays an active role in terms of maintaining position, changing position.
Dorothy Doty:So much higher metabolic rate, much higher rate of oxygen utilization, which means that the muscle layer is the layer that is most sensitive, most vulnerable to the effects of reduced blood flow, most vulnerable to ischemia.
Dorothy Doty:And that's the layer that's sitting right next to the bone.
Dorothy Doty:So when you lie or sit for prolonged periods, especially on an unyielding surface, you've got bone pressing right against the muscle, interfering with blood flow, causing ischemia and causing muscle damage.
Dorothy Doty:Most of your deep pressure injuries actually start at the bone muscle interface.
Dorothy Doty:So you think about your stage three, your stage four, your unstageables, and some of your deep tissue injuries.
Dorothy Doty:Where does that damage Start probably at muscle bone interface.
Dorothy Doty:Also important to recognize muscle does not regenerate.
Dorothy Doty:So once you get injury extending to the muscle, that muscle is lost and will be replaced with scar tissue if we can get it to heal.
Dorothy Doty:Okay, so we've talked about the structures of the skin.
Dorothy Doty:Now let's review the functions of the skin and then we'll talk about keeping the skin healthy.
Dorothy Doty:The critical, critical function is protection.
Dorothy Doty:We've talked about that a lot.
Dorothy Doty:That's what I really want you to remember.
Dorothy Doty:Now, there are some secondary functions.
Dorothy Doty:Definitely the skin and the related structures contribute to temperature control because you have blood vessels that can dilate or constrict.
Dorothy Doty:So dilate to contribute to evaporative loss, constrict to retain.
Dorothy Doty:You also have sweat glands that can contribute to evaporative loss or that can retain fluid.
Dorothy Doty:So definitely temperature control is affected by skin structures.
Dorothy Doty:Primary is protection.
Dorothy Doty:Yes, the skin contributes to excretion.
Dorothy Doty:When you sweat, you lose water and you lose sodium chloride.
Dorothy Doty:Very important in terms of sensory awareness.
Dorothy Doty:Contributes to vitamin D levels because sunlight activates steroids in the skin to produce vitamin D and an important component of body image, but the one I want you to remember, protection.
Dorothy Doty:Now, just a couple of other things.
Dorothy Doty:When you talk about normal skin flora, you know that your skin is crawling with organisms all the time.
Dorothy Doty:All of the little signs in our hospitals today remind us about all the organisms on our skin.
Dorothy Doty:Resident bacteria are literally organisms that live on the skin.
Dorothy Doty:So you're always going to find them there.
Dorothy Doty:It's like, this is my home.
Dorothy Doty:So Staphylococcus epidermidis, Corynebacterium.
Dorothy Doty:Those are resident bacteria.
Dorothy Doty:Transient bacteria are organisms that are not usually found on the sky.
Dorothy Doty:They're kind of just, you know, passing through.
Dorothy Doty:They're easily removed by routine hygiene.
Dorothy Doty:What you want to remember is there's always a lot of organisms on the skin.
Dorothy Doty:So if you are getting a wound, culture is absolutely critical, not only to flush the wound, but either to avoid the surrounding skin or to clean the surrounding skin so that you don't get them contaminating your culture.
Dorothy Doty:What about epidermal regeneration?
Dorothy Doty:How long does it take to replace lost keratinocytes with new keratinocytes?
Dorothy Doty:How long does it take a cell to go from the basement to the roof?
Dorothy Doty:Well, in young adults it's about 20 days.
Dorothy Doty:So they have that healthy, fresh looking skin.
Dorothy Doty:But as we age, the turnover time gets longer.
Dorothy Doty:By the time we're elderly, somebody looks at our skin and says, wow, looks like those cells have been there a while.
Dorothy Doty:Yes, they're waiting for their replacements.
Dorothy Doty:And it takes a lot longer for those cells to migrate from the basement to the roof because they're old, so they're kind of crawling up the steps.
Dorothy Doty:So we know that in young adults it's like 20 days.
Dorothy Doty:In older individuals it's 30 days.
Dorothy Doty:And the elderly it might be even longer than that.
Dorothy Doty:There's a couple of other things that are important to remember in terms of epidermal turnover.
Dorothy Doty:We talk about steroids and their negative impact on skin health and the fact that you get thinner skin in patients on steroids.
Dorothy Doty:Why is that?
Dorothy Doty:Well, one effect of steroids is to block epidermal reproduction in that basement membrane layer.
Dorothy Doty:Remember, you have these little cells down there that are producing new cells and sending them to the surface.
Dorothy Doty:But in a patient on steroids, the rate of reproduction is significantly reduced.
Dorothy Doty:So there's many fewer cells migrating toward the surface.
Dorothy Doty:Takes a lot longer to heal a surface wound.
Dorothy Doty:And the skin itself becomes much thinner, much more vulnerable.
Dorothy Doty:On the flip side, and in terms of good news, any kind of injury, any kind of skin loss stimulates reproduction at that basement membrane layer.
Dorothy Doty:So it's like a message goes out that says, hey guys, we have a defect measuring 4 by 6 on the right thigh.
Dorothy Doty:Until this defect is covered, everyone's working seven days a week, 12 hours a day.
Dorothy Doty:All leave is canceled.
Dorothy Doty:Now you've got very motivated keratinocytes.
Dorothy Doty:Reproduction speeds up, the defect is resurfaced, everything goes back to normal.
Dorothy Doty:So steroids slow reproduction and thin the skin injury stimulates reproduction to eradicate the defect.
Dorothy Doty:The last thing we're going to cover in this section is what are the things that we should be doing on a routine basis to keep the skin healthy.
Dorothy Doty:And when we talk about healthy skin, we're talking about an intact barrier.
Dorothy Doty:So what are the things we do every day?
Dorothy Doty:We clean the skin, we shower ourselves, we clean the skin for our patients.
Dorothy Doty:So what should we be thinking about?
Dorothy Doty:Well, we should be thinking we want the surface of the skin to remain acidic.
Dorothy Doty:So you're going to see a lot of cleansing products that are labeled PH balanced.
Dorothy Doty:If you can do patient cleansing with pH balanced, no rinse cleansers.
Dorothy Doty:It helps to keep the skin, number one, acidic, and it eliminates that soap film that can cause an irritant response and problems.
Dorothy Doty:So you're looking for ph balance.
Dorothy Doty:No rinse cleansers.
Dorothy Doty:Super fatted, non alkaline soaps can help to replace lost lipids and keep the skin soft and supple.
Dorothy Doty:What about chg?
Dorothy Doty:Because we see A lot of protocols that call for routine bathing with chlorhexidine gluconate, impregnated wipes, especially in high risk areas like our ICUs.
Dorothy Doty:And we have pretty good data that says that routine use of CHG based products does reduce the levels of pathogens on the skin and does reduce the incidence of central line associated skin infections.
Dorothy Doty:So can CHG bathing be a good thing?
Dorothy Doty:Yes, it can definitely reduce serious infections.
Dorothy Doty:Is it a bad thing?
Dorothy Doty:So I've heard anecdotal reports, I've talked to people who feel like they see more irritant reactions when they're bathing with chg.
Dorothy Doty:But so far we do not have any objective data that says that CHG increases skin reactions, allergic reactions or skin breakdown.
Dorothy Doty:So if you're in a system and you're using CHG based products to reduce skin infections and to reduce bloodstream infections, yes, you want to be adherent to that.
Dorothy Doty:One thing you should think about is when you're selecting emollient products to keep the skin soft and supple, you have to make sure that they're compatible with chg.
Dorothy Doty:Also, you have to think about age issues and we'll come back to this.
Dorothy Doty:But basically CHG has been found to be safe and effective all the way from two months throughout the lifespan.
Dorothy Doty:What about infants younger than two months?
Dorothy Doty:We do not have good data on those products in that patient population.
Dorothy Doty:So currently CHG is the recommended and accepted protocol for routine bathing of high risk individuals to reduce the incidence of skin infections and bloodstream infections.
Dorothy Doty:Ongoing research.
Dorothy Doty:So those recommendations may change.
Dorothy Doty:That's where we are right now, individualized bathing frequencies.
Dorothy Doty:So we know that older individuals produce lower levels of skin oils.
Dorothy Doty:Every time we bathe somebody, we tend to strip some of the skin oils.
Dorothy Doty:So in many agencies you'll see that bathing frequency for older individuals is reduced to every other day or three times a week instead of every day.
Dorothy Doty:And that makes good sense from a science perspective.
Dorothy Doty:We want to teach our care providers, so your nursing techs or CNAs or your home providers to use gentle technique and soft cloths when bathing the skin.
Dorothy Doty:A lot of us were taught, I started out as a CNA and a lot of us were taught cleanliness is next to godliness and we were going to scrub our patients cleaning.
Dorothy Doty:You still see a lot of scrubbing going on, but when you have fragile skin and you're cleaning vigorously with a hospital based washcloth, it's like taking sandpaper to their skin.
Dorothy Doty:So you want to rethink what are we trying to do.
Dorothy Doty:We're trying to remove organisms, we're trying to remove secretions.
Dorothy Doty:Were trying to keep the barrier intact.
Dorothy Doty:So gentle cleansing, non aggressive cloths.
Dorothy Doty:Okay.
Dorothy Doty:Non abrasive cloths with pH balanced, ceramide rich, oil rich products.
Dorothy Doty:So now we come down to moisturizers.
Dorothy Doty:And I want you to differentiate between emollients and humectants.
Dorothy Doty:Hemolliants are good for everyone.
Dorothy Doty:So emollients are basically oils.
Dorothy Doty:So you'll see a lot of your products.
Dorothy Doty:Now if you look at the ingredients, they'll talk about ceramides.
Dorothy Doty:A lot of hygienic products include ceramides.
Dorothy Doty:A lot of cosmetic products include ceramides.
Dorothy Doty:Because now there's increasing recognition that ceramides do fill the gaps between the skin cells and their critical skin oils.
Dorothy Doty:You'll see other skin oils incorporated in products.
Dorothy Doty:So dimethicone helps to fill gaps.
Dorothy Doty:Any kind of oil based product.
Dorothy Doty:So your lotions, your creams, your moisturizers are going to include emollients that penetrate the stratum corneum, fill the gaps between the cells.
Dorothy Doty:They're good for fragile skin, they're good for normalcy.
Dorothy Doty:What about humectants?
Dorothy Doty:Humectants are different.
Dorothy Doty:Humectants actively attract water to the skin.
Dorothy Doty:They're intended for extremely dry skin.
Dorothy Doty:For xerosis, your humectants are things like urea based products.
Dorothy Doty:So I'm trying to remember the name of one, I can't think of it right now.
Dorothy Doty:But your hydroxyurea products and also attractane, which is available over the counter, all of those are either urea based or they're another molecule that actively attracts water.
Dorothy Doty:Those are very appropriate for extremely dry skin, very appropriate for dry feet.
Dorothy Doty:Totally inappropriate for very fragile, macerated skin.
Dorothy Doty:You never want something that attracts water if the skin is already macerated.
Dorothy Doty:Most of these humectants have a desloughing effect because they're intended for that very dry, rough skin.
Dorothy Doty:And you don't want a desloughing effect on fragile skin.
Dorothy Doty:So emollients are appropriate for everyone.
Dorothy Doty:Humectants are appropriate only for patients with very dry skin.
Dorothy Doty:I thought of the other.
Dorothy Doty:The urea based product is lac hydrin.
Dorothy Doty:It's a prescription product, but you'll see dermatologists recommend that a lot for patients with extremely dry skin.
Dorothy Doty:And across the board, when you're applying emollients and humectants, you should apply them to barely damp skin because one of the things they do is lock in that moisture.
Dorothy Doty:What about common skin problems?
Dorothy Doty:What if you have somebody with itchy skin and they're constantly doing this and they tell you, my skin itches, I'm scratching all the time.
Dorothy Doty:That's how I got this, breaking the skin here.
Dorothy Doty:What are some things you can do to reduce itching?
Dorothy Doty:Well, of course you're going to use emollients, you're going to try to correct dry skin.
Dorothy Doty:But also you can use soothing products like Aveeno, which is oatmeal based, or Burro solution, which is aluminum acetate.
Dorothy Doty:So those are common products that are used in dermatology that you can recommend as well.
Dorothy Doty:What about your diabetic patients with dry, scaly feet or sometimes just older patients with very dry, scaly feet?
Dorothy Doty:Well, you can do a vinegar water soak where you do one part vinegar to three parts water, about a 10 to 15 minute soak.
Dorothy Doty:Why vinegar?
Dorothy Doty:Because it's acetic acid and it's a keratolytic, meaning it penetrates that very dry outer layer of skin and takes water into the skin itself.
Dorothy Doty:It has a desluffing effect.
Dorothy Doty:So when you take them out of the vinegar water soap, you can buff the skin and a lot of that dry skin will come off.
Dorothy Doty:And then you can apply either a heavy duty, heavy duty amalia like Aquaphor, Petrolatum, Eucerin, any of those, or you can use humectant like Lacydrin or a Tractane or something like that.
Dorothy Doty:Now I know you're thinking, hmm, you just said to do a soak.
Dorothy Doty:And I know that the current recommendations are do not do soaks for diabetic feet.
Dorothy Doty:So let's think through that.
Dorothy Doty:Why do we tell diabetic patients, don't soak your feet?
Dorothy Doty:Number one, we're concerned that they won't check the temperature of the water and they'll burn their feet.
Dorothy Doty:Number two, we're concerned that they won't dry well between their toes and they'll get fissures.
Dorothy Doty:But if you're the provider, you can control the temperature and you can make sure that you dry well between the toes.
Dorothy Doty:So yes, brief soaks are appropriate and are safe if you're in charge.
Dorothy Doty:We have many, many patients with thin, fragile skin.
Dorothy Doty:Our elderly patients, our critically ill patients, our very malnourished patients.
Dorothy Doty:And so it all comes down to gentle care, gentle technique and routine use of emollients.
Dorothy Doty:Your oil based products penetrate the stratum corneum, fill the gaps between the skin cells, help to keep the skin healthy, help to maintain that barrier.
Dorothy Doty:When should you send a patient to dermatology?
Dorothy Doty:Anytime that you see a problem that you're not sure what it is, you're not sure what should be done.
Dorothy Doty:Or maybe you thought you knew what was going on and so you initiated management, but it was ineffective.
Dorothy Doty:Never, ever hesitate to refer.
Dorothy Doty:When you look at the dermatology textbooks and you see they're hundreds of pages long, you know, there's many, many things that can go wrong with the skin.
Dorothy Doty:We know about this many of them.
Dorothy Doty:So everything else goes to dermatology.
Dorothy Doty:If in doubt, refer.
Dorothy Doty:Okay, so in summary, you're almost to a break.
Dorothy Doty:Normal skin is acidic and supple.
Dorothy Doty:That's always your goal.
Dorothy Doty:Maintain acid ph, keep the skin soft and supple.
Dorothy Doty:The epidermis, outer layer, 20 cell layers thick.
Dorothy Doty:The only actively living reproducing layer is that basal layer.
Dorothy Doty:The epidermis is the critical layer in terms of barrier function.
Dorothy Doty:The dermis provides strength and support to the skin.
Dorothy Doty:Primary components of the dermis are collagen and elastin.
Dorothy Doty:The subcutaneous layer, remember, is critical in terms of padding and protection.
Dorothy Doty:And the muscle layer has the highest metabolic rate and is the most vulnerable to loss of blood flow to ischemia across the board.
Dorothy Doty:What should you do to keep the skin healthy?
Dorothy Doty:Use products that are ph balanced so that you maintain that acid mantle.
Dorothy Doty:Use moisturizers on a routine basis to replace skin lipids so that you maintain that intact brick wall.
Dorothy Doty:Manage dry skin and pruritus so that you don't get cracks in the skin from scratching.
Dorothy Doty:Okay, so that's it for part one.
Dorothy Doty:And when you're ready, we'll move on to part two.
Dorothy Doty:Thank you.
