Pressure Injury Staging and Wound Care

In depth

The one-page summary above is what the PDF prints. These sections go further.

How pressure injures tissue

Skin and muscle caught between bone and a bed, chair or device lose blood flow once the load exceeds capillary pressure (about 12 to 32 mm Hg, Merck), and injury can start within 3 to 4 hours. Shear (layers sliding over each other, as when a client slides down a raised bed) stretches and tears small vessels; friction and moisture weaken the surface. Muscle is less tolerant of ischemia than skin, so damage often begins deep at the bone and spreads outward: a small surface opening can hide a large cavity, and a deep tissue injury can open into a stage 3 or 4 wound within days.

The sacrum is the most common site, then the heels; the ischial tuberosities (sitting), trochanters, malleoli and occiput (long surgery, supine ICU patients) follow. Devices add their own sites: the nasal bridge under a mask, the lip under an endotracheal tube, the nares under a feeding tube, the ear under oxygen tubing, the neck under a collar.

Staging in practice

Stage by the deepest tissue you can confirm. Once bone or tendon is exposed or can be felt in the wound bed, depth is known and the wound is stage 4 even if some slough remains; the unstageable label is only for a wound whose base is hidden. After debridement uncovers the base, the unstageable wound is staged. Stage numbers are not a ladder: a stage 3 need not have started as a stage 1, and a stage 1 need not progress.

Stage 2 is easy to over-call. Moisture-associated damage, incontinence dermatitis and skin tears are not pressure injuries and are not staged. A blood-filled blister is a deep tissue injury, not stage 2. A purple or maroon area is not stage 1. In darkly pigmented skin, compare warmth, firmness and tenderness with the skin nearby, use good light, and remove barrier creams before looking.

A device-related injury on skin takes the device’s shape and is staged like any other; "device-related" names the cause. Injury on a mucous membrane cannot be staged because the tissue has no comparable layers.

Eschar that is dry, adherent, intact and without redness, fluctuance or drainage on a heel or in a limb with poor arterial flow acts as a natural cover and is not softened (no collagenase) or removed. If it becomes boggy, red, fluctuant or starts to drain it is no longer stable and needs prompt evaluation.

Risk in the ICU

A systematic review of critical-care studies found age, reduced mobility, poor perfusion (diabetes, vascular disease) and vasopressor infusion to be the most consistent risk factors; vasopressors predicted injury in four of six studies that tested them (Alderden 2017). Sedation, shock, prolonged surgery and devices add to this. Risk scales used in critical care rate nearly everyone high risk, so they help less with ranking ICU patients than with prompting a prevention plan.

Unstable patients who cannot tolerate full turns still get small frequent shifts, heel floating and device checks. After long operations such as cardiac surgery, check the head, sacrum and heels, and a new red area found afterward is assessed and offloaded like any other.

Support surfaces and repositioning

Static surfaces (high-specification foam, gel, air, water) need no power; dynamic surfaces (alternating pressure, low-air-loss, air-fluidized) do. Egg-crate overlays give no advantage (Merck). Turning still matters on any surface. Chair-bound clients sit for shorter periods, reposition about hourly and shift their own weight about every 15 minutes, leaning forward and to each side. Donut cushions concentrate pressure on the ring and are avoided.

Pillows go under the calves so the heels float; a pillow under the knees pushes the heels down. On the side, a pillow between knees and ankles stops bone pressing on bone. Keeping the head of the bed at 30° or lower limits shear, balanced against aspiration precautions (see Client Positioning).

Moisture and incontinence

Incontinence-associated dermatitis is moisture-associated skin damage from urine and stool. Alkaline soap raises skin pH and strips lipids, so care uses a no-rinse cleanser near skin pH (Banharak 2021 gives pH 4 to 6.8), gentle patting rather than rubbing, a zinc oxide, dimethicone or petrolatum barrier after every episode, and a breathable pad instead of a closed brief. Powder cakes and irritates. Satellite red spots at the edges suggest a yeast infection and need antifungal treatment as ordered.

Dermatitis and early pressure injury are hard to tell apart and often occur together: in a multisite survey, clients with incontinence dermatitis had about four and a half times the odds of a sacral pressure injury after adjustment for immobility (Gray and Giuliano 2018). Treat the moisture and offload the area.

Wound beds, debridement and dressings

Healthy granulation is pink-red, moist and bumpy and does not bleed easily; dark red, friable tissue that bleeds with touch suggests infection or biofilm. Slough (yellow, stringy) and eschar (black, leathery) usually must be removed for healing, except stable heel eschar. Debridement can be autolytic (moist dressings let the wound’s own enzymes work; small, low-drainage, uninfected wounds), enzymatic (a prescribed agent such as collagenase, usually daily), mechanical (wet-to-dry gauze, painful and nonselective) or sharp (a trained clinician with scalpel or scissors, at the bedside or in the operating room).

Films and hydrogels suit wounds with little drainage and can stay 3 to 7 days; hydrocolloids suit light drainage; foams handle variable drainage and come in waterproof versions useful with incontinence; alginates and gelling fibers absorb heavy drainage and are changed when saturated. Alginate can look green on removal and is not pus. Pack deep wounds loosely so packing comes out easily and does not crush granulation. Antiseptics such as peroxide, povidone-iodine and acetic acid damage healing tissue.

Healing, nutrition and infection

Healing runs through hemostasis (up to about an hour), inflammation (redness, swelling, some serous drainage), proliferation (granulation, new capillaries, contraction, new epithelium) and maturation, when collagen strengthens the scar over months. Healing slows with poor perfusion or oxygenation, diabetes, smoking, older age, corticosteroids, obesity, malnutrition and stress. Low hemoglobin, low albumin, high glucose or HbA1c and poor kidney function on labs point to these causes.

All open pressure injuries are colonized, so routine swabs are not sent. A culture is sent when signs of infection appear, preferably of tissue. Fever and leukocytosis raise concern for cellulitis, bacteremia or osteomyelitis; osteomyelitis is present in up to 32% of clients with pressure injuries and is suspected when a deep wound stops healing. The workup includes a CBC, blood cultures, ESR and CRP or procalcitonin, with bone biopsy to confirm (Merck).

Surgical site infection usually appears within 30 days of surgery: redness, warmth, pain, purulent drainage and fever. The surgeon may remove staples or sutures to open and drain the wound, send pus or tissue for culture, and start antibiotics; the open wound then heals by secondary intention, sometimes with a wound vacuum.

Drains and negative-pressure therapy

Closed suction drains pull fluid from a surgical bed: a Hemovac holds up to about 500 mL; a Jackson-Pratt bulb serves smaller volumes. To empty one, open the port away from your face, pour into a measuring container, squeeze the reservoir flat, and cap it while compressed so the vacuum returns. Pin it to the gown below the wound, record each drain separately, and report unusual drainage, a change in amount or signs of infection. A marked fall in output may mean the drain is ready to come out.

Negative-pressure wound therapy seals foam in the wound under film and connects it to a pump, commonly at −125 mm Hg, to remove drainage and draw the edges together; dressings are usually changed every 2 to 3 days. Therapy is meant to run most of the day (about 24 h in Open RN and the Kaiser patient instructions; a review advises at most 22 h so tissue can rest, with brief disconnections for meals or walks). A children’s hospital patient handout says never to leave foam in the wound longer than 2 hours with the vacuum off or not working: the dressing is removed, the wound washed and a new dressing applied. FDA reports named bleeding as the most serious complication, especially with vascular grafts, sternal or groin wounds, anticoagulants, and dressings stuck to tissue; retained foam pieces caused infection. Contraindications include necrotic tissue with eschar, untreated osteomyelitis, unexplored fistulas, malignancy in the wound and exposed vessels, nerves, anastomoses or organs. Clients at home are taught to seek help at once for bright red blood in the tubing or canister.

Dehiscence and evisceration

Dehiscence occurs in fewer than 3% of abdominal operations but carries a reported mortality of 14 to 50%, higher with evisceration (Downey 2020). Risks include obesity and raised abdominal pressure (distention, ileus, coughing, vomiting), diabetes, steroids, malnutrition, smoking and infection. A healing ridge should be felt along the incision by about days 5 to 9; its absence, new serosanguineous drainage, or a feeling that something gave way are warnings.

The nurse stays, calls for help, places the client in low Fowler with knees bent to relax the abdomen, covers the wound or organs with sterile saline-moistened gauze, keeps the client NPO for surgery, and watches for shock. Teaching: splint the incision with a pillow to cough or sneeze and avoid lifting 10 lb or more for 6 to 8 weeks, or as the surgeon directs.

Regulation and documentation

In nursing homes, 42 CFR 483.25(b)(1), surveyed as F686, requires care that prevents pressure ulcers unless the resident’s condition made them unavoidable, and treatment that promotes healing, prevents infection and prevents new ones. Open RN notes that injuries acquired or worsening in hospital are treated as never events, and CMS and many insurers do not pay the added costs. Accurate admission skin checks, consistent measurement and stage documentation protect both the client and the record.