Nursing Field Notes / Skin & Wound · Pressure Injuries · Pathophysiology + Fundamentals

🩹 SKIN & WOUND SET NG-051 Skin (foundation) NG-044 Pressure Injuries NG-080 Wound Care NG-116 Frostbite NG-182 Dermatitis NG-225 Psoriasis NG-204 Skin Cancer

Pressure Injuries 🛏️

Staging 1 → 4 + unstageable + deep tissue — and the prevention that makes all of it unnecessary

NG-044 INTEGUMENTARY · SAFETY ADHD-friendly visual edition

A pressure injury is localized damage to skin and underlying soft tissue, usually over a bony prominence or under a medical device, caused by pressure — or pressure plus shear. Staging is nothing more than counting the layers you can see on the cross-section from NG-051. Learn that picture and staging answers itself.

📄 Simple Nursing original — opens in Drive →

🪜 Stage = layers lost1 = intact red · 2 = epidermis + dermis · 3 = into fat · 4 = bone/tendon/muscle.

🚨 Can't see the base?Covered by slough or eschar = UNSTAGEABLE, not Stage 4.

🕑 Turn q2h in bedq1h in a chair · 30° lateral tilt · float the heels.

❌ Never massageNever massage a reddened bony prominence. Never reverse-stage a healing wound.

🧨

WHY IT HAPPENS

STEP 1 · CAUSE

Squash a capillary long enough and the tissue it feeds dies. Everything else on this page follows from that one sentence.

🧨 The mechanism — a capillary crushed between bone and mattress

Two variables decide the damage: how much pressure, and for how long. Very high pressure for a short time and modest pressure for a long time both kill tissue — which is why an immobile patient on an OR table, or a patient who slid down the bed and stayed there, can injure in hours.

🧠 "Muscle dies first, skin dies last." Muscle has the highest oxygen demand and sits closest to the bone. That is the entire explanation for deep tissue pressure injury — the disaster is already deep when the surface still looks nearly normal.

🧨 Pressure vs shear vs friction vs moisture — four different enemies

Exam trap: moisture-associated skin damage (MASD / incontinence-associated dermatitis) is not a pressure injury and is not staged — it is diffuse, in the moisture pattern, often not over a bony prominence. The same is true of skin tears and tape injuries. Moisture multiplies pressure injury risk, but it is a separate diagnosis.

🧠 Pressure pushes down. Shear pulls apart. Friction scrapes. Moisture softens. Head-of-bed too high = pressure AND shear at the sacrum at the same time — the single most common set-up in the hospital.

🚨 Where they come from — the two sources

Bony prominence + surface — the classic. Sacrum/coccyx, heels, ischial tuberosities, trochanters, elbows, occiput, ears, scapulae, malleoli.
Medical device — the fastest-growing category and the most missed. Oxygen tubing behind the ears and across the cheeks, nasal cannula, CPAP/BiPAP mask bridge of nose, ETT and tube holders, cervical collars, casts and splints, pulse-ox probes, SCD sleeves, catheter tubing left under a thigh, IV hubs, drain tubing.

A device-related injury takes the shape of the device. If the wound is a neat line or a mask outline, look for what was sitting there.

🧠 "If it's on the patient, look under it." Every shift, lift and inspect under every tube, strap and probe — and rotate probe sites.

⚠️ Who gets them — the risk stack

🛏️Immobilebedbound, sedated, paralyzed

💧Incontinentmoisture + friction

🍽️Poor nutritionlow protein, low albumin

🍬Diabetesneuropathy + poor perfusion

🫀Poor perfusionPVD, shock, vasopressors

👵Age > 65thin skin, less fat

🧠↓ Sensationcan't feel the pain that makes you move

🩺Cirrhosislow albumin → edema

Albumin reference 3.5–5.0 g/dL. Low albumin means poor protein status and edema, which widens the diffusion distance from capillary to cell — the tissue starves even with blood flowing.

🧠 "Can't move it, can't feel it, can't feed it, can't perfuse it." Four cannots — the more the patient has, the sooner you start prevention.

🪜

STAGING — COUNT THE LAYERS

STEP 2 · THE BIG ONE

The single most tested content on this page. Same cross-section, six times, each one deeper.

🪜 The staging plate — one drawing per stage

epidermis dermis subcutaneous fat muscle bone slough eschar

🧠 The stage number = the number of layers destroyed. 1 = epidermis (still intact, just red) · 2 = epidermis + dermis · 3 = + subcutaneous fat · 4 = + muscle/tendon/bone. If you cannot see the bottom, you cannot count — so it is unstageable.

⭐ Staging table — the version to memorize

Stage	Skin intact?	What you see	Depth	Trap
Stage 1	YES	Non-blanchable erythema over a bony prominence; may be firm, boggy, warmer/cooler, painful	Epidermis	In darker skin it may look purple/maroon or just different — palpate for temperature and induration
Stage 2	NO — open	Shallow open ulcer, pink/red, moist, shiny wound bed; or an intact/ruptured serum-filled blister	Epidermis + partial dermis	No slough, no eschar, no fat. Do not use Stage 2 for skin tears, tape injury, incontinence rash or maceration
Stage 3	NO	Full-thickness crater; fat may be visible; slough may be present; undermining/tunnelling common	Through dermis into subcutaneous	Depth varies by site — the ear, occiput, nose and malleolus have almost no fat, so a Stage 3 there can be shallow
Stage 4	NO	Exposed or palpable muscle, tendon, fascia, ligament, cartilage or bone; slough/eschar may be present	All layers	Highest risk of osteomyelitis and sepsis
Unstageable	NO	Base obscured by slough (yellow/tan/gray/green, stringy) or eschar (tan/brown/black)	Full thickness — depth unknown	It becomes a Stage 3 or 4 only after debridement reveals the base
Deep tissue pressure injury	May be intact	Persistent non-blanchable deep red, maroon or purple discoloration, or a blood-filled blister	Damage begins at the bone–muscle interface	Not a bruise and not Stage 1. Can deteriorate to a full-thickness wound within days even with ideal care

🧠 "Blood-filled = deep tissue. Serum-filled = Stage 2." The color of the blister fluid is the whole question.

🚨 Eschar & slough — the two words that decide "unstageable"

Eschar — black/brown, dry, leathery, dead tissue. Es-CHAR-coal = charcoal black.
Slough — yellow/tan/gray, soft, moist, stringy dead tissue. Looks like the slippery skin of a raw chicken.
Either one covering the wound base = UNSTAGEABLE until it is removed.
Do NOT remove stable eschar on the heels — dry, adherent, intact, with no erythema or fluctuance. It is acting as the body's natural biological cover. Protect and offload it, and report any change (new redness, swelling, drainage, odor, softening) at once.

🧠 EsCHARcoal is black. Slough sloughs off like chicken skin. Neither lets you count layers, so neither lets you stage.

❌ Never reverse-stage

A pressure injury does not go back up the scale as it heals. Full-thickness wounds fill with granulation and scar tissue — they never regrow fat, muscle or dermis.

A healing Stage 4 is documented as a "healing Stage 4" — never "now a Stage 2".
Track healing with measurements (length × width × depth in cm), tissue type in the bed, exudate, and wound-edge condition — not by dropping the stage number.
Once staged, the stage is the highest stage that wound ever reached.

🧠 Stages only go up. Like a scar, the history is permanent.

📐 Measuring & documenting the wound — the clock method

🧠 12 o'clock is always the patient's head. Length head-to-toe, width side-to-side, depth with a moistened sterile applicator — then say where the hidden damage is by the clock.

📍

RISK SCORE & PRESSURE POINTS

STEP 3 · FIND IT EARLY

Score the risk, then know exactly where to look — the sites change with every position.

📍 Pressure points by position

🧠 Position tells you the points. On the back → sacrum + heels. On the side → trochanter + ear. Face down → chest + knees + toes. Sitting → ischial tuberosities. Say the position out loud before you inspect.

📊 The Braden Scale — score the risk before the wound exists

Use the subscales, not just the total. A patient scoring low on moisture needs barrier cream and an incontinence plan; one scoring low on mobility needs a turning schedule and a support surface. Reassess on admission, with any change in condition, and per policy (commonly every 24–48 h in acute care).

🧠 BS = Braden Scale · BS = Broken Skin. And remember low score = big trouble — it runs the opposite way to most scores you know.

⭐ Also monitor these numbers

Albumin 3.5–5.0 g/dL — low = poor protein stores, edema, slow healing. (Prealbumin responds faster to changes in intake.)
Urine output ≥ 30 mL/hr — below this signals inadequate perfusion/hydration, which starves the wound too.
Fluids commonly 2–3 L/day unless fluid-restricted.
Weight and intake — unintentional weight loss is a red flag for skin breakdown.
Hemoglobin, glucose (A1c), and prealbumin — anemia, hyperglycemia and malnutrition all slow healing.

🧠 Skin is a protein organ. No protein, no repair — the wound is a construction site with no bricks.

🚨 Signs the wound is now infected — escalate

New or spreading erythema, warmth, edema around the wound; induration
Purulent, thick or foul-smelling drainage; a sudden increase in exudate
New or increased pain; friable, bleeding granulation; wound stops progressing or gets bigger
Fever, chills, tachycardia, hypotension, confusion (especially the sudden confusion of an older adult) → think sepsis
Exposed bone in a chronic wound → suspect osteomyelitis

🧠 A clean healing wound gets smaller, pinker and less painful. Bigger, smellier and more painful = call.

🛡️

PREVENT & TREAT

STEP 4 · CARE

Prevention is the whole exam answer. Almost every "which action first?" question here is about offloading pressure.

🕑 Repositioning, the 30° rule, and floating heels

🧠 "Two in bed, one in the chair, thirty on the side, zero on the heel." Four numbers cover most prevention questions.

✅ The prevention bundle — do all of it, every shift

Assess & score
Full skin assessment on admission (within the first 24 h per most policies), Braden score, then reassess per policy and with any change.

▼

Offload
Turn q2h in bed, q1h in a chair; 30° tilt; HOB ≤30°; float heels; lift sheet — never drag.

▼

Support surface
Pressure-redistributing mattress/overlay and a proper seat cushion for at-risk patients. No donut/ring cushions — they concentrate pressure in a circle and cause ischemia.

▼

Manage moisture
Clean promptly after incontinence, pat dry, apply a barrier cream/film; consider absorbent products; treat diarrhea.

▼

Feed & hydrate
Protein and calories, fluids 2–3 L/day unless restricted; dietitian referral for at-risk patients.

▼

Look under every device
Rotate oximeter probes, pad tubing and mask edges, check ears/nose/neck/heels every shift.

🧠 ASSESS · OFFLOAD · SURFACE · DRY · FEED · DEVICES. Six steps, in that order, every single shift.

❌ Never-do list

Never massage a reddened bony prominence — it shears already-damaged capillaries.
Never use a donut / ring cushion.
Never drag a patient up the bed — friction plus shear. Use a lift sheet and two people or a mechanical lift.
Never remove stable, dry, intact eschar from a heel without an order — it is a biological cover.
Never reverse-stage a healing wound.
Never leave the head of the bed high "for comfort" without checking the sacrum — that is the shear machine.
Never assume a device is fine because the patient hasn't complained — sedated and neuropathic patients cannot tell you.

🧠 If an option in a question says massage the red area or place a donut cushion, it is wrong. Every time.

🩹 Treating what already exists — matched to the stage

Stage	Goal	Typical approach
Stage 1 / DTPI	Protect and offload — nothing to fill	Remove all pressure from the site, transparent film or a soft silicone foam dressing for protection, treat moisture, reassess frequently. DTPI can still deteriorate — document and monitor closely.
Stage 2	Keep it moist and covered, protect new epithelium	Hydrocolloid or thin foam dressing; keep the periwound dry; do not disturb an intact blister unnecessarily.
Stage 3	Fill dead space, absorb exudate, remove dead tissue	Loosely pack with a moist filler (e.g. gauze or alginate depending on exudate) and cover; debride slough; measure undermining/tunnelling every dressing change. Pack loosely — tight packing causes more pressure.
Stage 4	Same, plus protect exposed structures & find infection	Surgical/sharp debridement, advanced dressings, possible negative-pressure wound therapy, wound-care and surgical consult; watch for osteomyelitis and sepsis.
Unstageable	Reveal the base — unless it is stable heel eschar	Debridement (sharp/surgical, enzymatic, autolytic, mechanical) per order, then re-stage. Stable dry heel eschar: protect, offload, do not debride.

The dressing logic, the healing phases, debridement types and the full documentation checklist live on the partner page: NG-080 — Wound Care.

🧠 Moist wound bed, dry wound edges. That single sentence drives nearly every dressing choice.

👨‍👩‍👧 Teach the patient and family

Why turning matters — "the skin needs its blood back every couple of hours."
Check the skin daily, including with a mirror for the sacrum and heels at home.
Report early: a red area that doesn't fade within about 30 minutes of relieving pressure, any new pain, or any open area.
Eat the protein and drink the fluids; keep skin clean and dry.
Wheelchair users: shift weight every 15 minutes, use a prescribed cushion, never a ring.
Keep sheets wrinkle-free and crumb-free; avoid rough seams and plastic under-pads directly on skin.

🧠 "Red that won't fade = phone the nurse." Give the family one clear trigger and they will use it.

🗺️ Where this page sits in the set

NG-051 — Skin: the cross-section every stage on this page is drawn on, plus lesion vocabulary and the blanch test.
NG-080 — Wound Care: the partner page. Healing intentions and phases, dressing selection, drains, dehiscence and evisceration.
NG-116 — Frostbite: the same depth logic caused by cold rather than pressure.

🧠 NG-044 = how deep is it? NG-080 = what do I put on it? Learn them as a pair.

⚡

QUICK RECALL

SAY IT OUT LOUD

🪜 Stage = layers lost1 intact red · 2 into dermis · 3 into fat · 4 to bone.

🚨 Slough or eschar = unstageableEsCHARcoal is black. Slough is yellow & stringy.

🕑 2 · 1 · 30 · 0q2h in bed · q1h in chair · 30° tilt & HOB ≤30° · heels touch nothing.

📊 Braden: low = bad6–23. Six subscales; friction & shear only goes 1–3.

🎯 Cover & check — 9 rapid-fire questions

Q1: Define a Stage 1 pressure injury.

Intact skin with localized non-blanchable erythema, usually over a bony prominence. It may feel firm or boggy, warmer or cooler than surrounding tissue, and be painful. In darker skin the color change may be purple/maroon rather than red.

Q2: A sacral wound has a base covered in yellow stringy tissue. What stage?

Unstageable. Slough (or eschar) obscures the base, so the depth cannot be determined until it is debrided.

Q3: Serum-filled blister vs blood-filled blister — what do they mean?

Serum-filled (clear) = Stage 2. Blood-filled (maroon/purple) = deep tissue pressure injury, which signals damage that started at the bone–muscle interface and may open into a full-thickness wound.

Q4: You find dry, black, intact, adherent eschar on a heel with no redness or drainage. What do you do?

Leave it alone. Stable, dry, adherent heel eschar acts as the body's natural biological cover. Offload and protect the heel, and report any change — new erythema, swelling, fluctuance, drainage or odor.

Q5: What are the pressure points in the side-lying position?

Ear, acromion/shoulder, greater trochanter, lateral knee/condyle, and the malleolus (ankle). Use a 30-degree tilt with pillows rather than a full 90-degree side-lie so the trochanter is not directly loaded.

Q6: Why is the head of the bed kept at 30 degrees or less?

Higher elevation makes the patient slide down. The skeleton moves while the skin stays stuck to the sheets, producing shear that tears the deep tissue over the sacrum — pressure plus shear together.

Q7: Name three things you must never do.

Never massage a reddened bony prominence; never use a donut/ring cushion; never drag a patient up the bed. (Also: never reverse-stage, and never debride stable dry heel eschar without an order.)

Q8: A healing Stage 4 now looks shallow with pink granulation. How is it documented?

As a "healing Stage 4." You never reverse-stage — full-thickness wounds fill with granulation and scar, not with new dermis, fat or muscle.

Q9: A Braden score comes back at 11. What does that mean and what do you do?

High risk (commonly 10–12 = high risk; lower score = higher risk). Start the full prevention bundle: turning schedule, pressure-redistributing surface, moisture management with barrier cream, nutrition/dietitian referral, heel offloading, and inspect under all devices — and look at which subscales are driving the score.