Wound Healing and Dressing Principles

To help with a wound safely, you need to understand what you are looking at: how it heals, what healthy tissue looks like and why a nurse chooses one dressing over another. This guide goes into that detail. It is written for care workers who assist the nurse, so it covers more than most aides will ever do alone. Who may touch a wound depends on your state, your employer and the care plan. If a task is not in your role, you observe, report and call the nurse.

What You Will Be Able to Do

• Describe the four phases of wound healing.
• Tell common wound types and tissue types apart.
• Measure and describe a wound accurately when asked.
• Explain why wounds are cleaned and dressed the way they are.
• Recognize local and spreading infection.

Understanding Wound Healing

Before you can care for a wound, you need to understand how the body heals itself.

Phases of Wound Healing

Phase 1 - Hemostasis (seconds to minutes): Blood vessels constrict to reduce blood flow. Platelets form a clot. This is the body's emergency response to stop bleeding.

Phase 2 - Inflammation (about 1 to 4 days): Blood vessels dilate, bringing white blood cells to the wound. The area becomes red, warm, swollen, and painful. This is a normal immune response, not an infection. White blood cells clean up dead tissue and bacteria.

Phase 3 - Proliferation (4-21 days): New blood vessels grow into the wound (angiogenesis). Fibroblasts produce collagen, which forms the structural framework of new tissue. Granulation tissue (beefy red, bumpy tissue) fills the wound from the bottom up. Epithelial cells migrate across the surface to close the wound.

Phase 4 - Maturation/Remodeling (21 days to 2 years): Collagen reorganizes and strengthens. The scar matures, becoming thinner, flatter, and lighter over time. The final scar is only about 80% as strong as the original tissue.

Factors That Impair Healing

Understanding these factors helps you identify patients at risk for poor wound healing:

• Age: Elderly patients heal more slowly due to reduced collagen production and slower immune response
• Nutrition: Protein, vitamin C, zinc, and iron are essential for wound healing. Malnourished patients heal poorly.
• Diabetes: High blood sugar impairs white blood cell function and reduces circulation to extremities
• Circulation problems: Peripheral vascular disease, venous insufficiency, and arterial disease all impair blood flow to wounds
• Medications: Steroids, chemotherapy, and immunosuppressants slow healing
• Smoking: Nicotine constricts blood vessels and reduces oxygen delivery to tissue
• Infection: Active infection keeps the wound in the inflammatory phase and prevents progression
• Moisture imbalance: Too much moisture (maceration) or too little (desiccation) both impair healing
• Pressure: Continuous pressure on a wound reduces blood flow and prevents healing
• Obesity: Adipose tissue has poor blood supply

Types of Wounds

Acute Wounds

• Abrasion: Skin scraped or rubbed away (road rash, carpet burn). Typically shallow, painful, and heals well with proper care.
• Laceration: A cut or tear, often from a sharp object. May be deep with irregular edges. May require sutures or staples.
• Puncture: A small, deep hole from a pointed object (nail, thorn, animal bite). High infection risk because bacteria are pushed deep into tissue.
• Avulsion: Skin or tissue torn partially or completely away. May require surgical repair.
• Surgical incision: A clean, deliberate cut closed with sutures or staples. It heals by primary intention, meaning the edges are held together.
• Burn: Tissue damage from heat, chemicals, electricity, or radiation. Classified by depth: first degree (superficial, red skin), second degree (partial thickness, blisters), third degree (full thickness, white or charred).

Chronic Wounds

Chronic wounds are wounds that do not progress through normal healing phases in the expected timeframe (usually 30 days). Common types:

• Pressure injuries (pressure ulcers, bedsores): Caused by prolonged pressure on the skin, typically over bony prominences.
• Venous stasis ulcers: Caused by poor venous return in the lower legs. Typically located on the inner ankle, shallow, irregularly shaped, with a lot of drainage.
• Arterial ulcers: Caused by poor arterial blood flow. Typically located on the toes, feet, or outer ankle. Deep, well-defined edges, pale wound bed, minimal drainage. Very painful.
• Diabetic foot ulcers: Caused by a combination of neuropathy (loss of sensation), poor circulation, and immune dysfunction. Often located on the bottom of the foot. The patient may not feel pain because of neuropathy, which makes these ulcers dangerous.
• Skin tears: Common in elderly patients with fragile skin. The epidermis separates from the dermis, creating a flap.

Observing a Wound

A nurse is responsible for the wound assessment. Your careful description helps. Note what you see at each dressing change you take part in.

What to Note

Location: Use anatomical terminology. "2 cm wound on the medial aspect of the left ankle" is better than "wound on the leg."

Size: Measure in centimeters.

• Length: longest measurement from head to toe, along the long axis of the body
• Width: widest measurement side to side, at a right angle to the length
• Depth: measured by the nurse at the deepest point

Write size as length x width x depth, in centimeters.

Wound bed appearance:

• Red/pink (granulation tissue): Healthy. Beefy red, bumpy tissue. This is the wound healing.
• Yellow (slough): Devitalized tissue. Soft, moist, yellow or tan. Needs to be removed for healing to progress.
• Black (eschar/necrotic tissue): Dead tissue. Hard, dry, black or brown. Must be removed (debrided) for healing, unless it is a stable eschar on a heel (which may be left intact per physician order).
• Mixed: Wound beds often have multiple tissue types. Describe the percentage of each: "60% red granulation, 30% yellow slough, 10% black eschar."

Drainage (exudate):

• Amount: None, scant, small, moderate, large, or copious
• Type: Serous (clear, straw-colored), sanguineous (bloody), serosanguineous (pink, blood-tinged), purulent (thick, opaque, may be yellow, green, or brown)
• Odor: Normally minimal. A foul odor may indicate infection or necrotic tissue.

Wound edges:

• Well-defined or irregular?
• Attached or detached (undermining)?
• Rolling under (epibole)? This prevents wound closure.

Surrounding skin:

• Color: Redness (erythema) may indicate inflammation or infection
• Temperature: Warm to touch may indicate inflammation or infection
• Moisture: Maceration (white, soggy skin from excess moisture) indicates the wound is too wet
• Integrity: Is the surrounding skin intact or breaking down?

Undermining and tunneling:

• Undermining: Tissue destruction under the wound edges. Documented using the clock method: "Undermining extends 2 cm from 2 o'clock to 5 o'clock."
• Tunneling: A narrow channel extending from the wound into surrounding tissue. Document the location and depth: "Tunnel at 3 o'clock, 3 cm deep."

Pain: Ask the patient to rate wound pain (0-10 scale). Note whether pain is constant, increases with dressing changes, or occurs at specific times.

Wound Cleaning

How Cleaning Works

• Follow the technique in the care plan. Sterile technique is usually for deep or surgical wounds with a high infection risk. Clean technique is common for chronic wounds at home.
• The standard wound cleansing solution is normal saline (0.9% sodium chloride)
• Do not use hydrogen peroxide, povidone-iodine (Betadine) or alcohol on open wounds unless they are specifically ordered. They are cytotoxic, meaning they kill healthy cells and delay healing along with bacteria and delay healing.
• Clean from the center of the wound outward, or from the cleanest area to the dirtiest
• Use gentle pressure. High-pressure irrigation (using a syringe with an 18-gauge needle or commercial wound irrigation device) is effective for removing debris but should only be done as ordered.

Cleaning Steps, When Delegated

1. Wash your hands. Put on clean gloves.
2. Remove the old dressing gently, in the direction of hair growth. If it sticks, moisten it with normal saline and wait a moment.
3. Observe the old dressing: how much drainage? What color? Any odor? These observations are part of your assessment.
4. Discard the old dressing and soiled gloves. Wash your hands. Put on new clean gloves (or sterile gloves if the care plan requires sterile technique).
5. Pour normal saline over the wound or irrigate gently with a syringe. Let the fluid run across the wound and collect on the pad beneath.
6. Using gauze moistened with saline, gently wipe from the center of the wound outward. Use a new piece of gauze for each wipe. Do not go back and forth with the same piece.
7. Pat the surrounding skin dry with clean gauze. Excess moisture on the surrounding skin causes maceration and skin breakdown.

Dressing Types and Selection

The nurse or provider chooses the dressing. A wound heals fastest when it stays moist, not wet and not dry, because cells grow and move more easily. It also needs protection from contamination.

Dressing Selection Guide

Gauze:

• The most versatile and widely available dressing
• Can be used wet (saline-moistened) for packing wounds or dry as a cover
• Requires frequent changes (may dry out and stick to the wound bed)
• Good for packing deep wounds with dead space
• Often used as a secondary (outer) dressing over other primary dressings

Transparent film (Tegaderm, OpSite):

• Clear, adhesive, waterproof
• Allows you to monitor the wound without removing the dressing
• Best for: shallow wounds, skin tears, IV sites, Stage 1 pressure injuries
• Not for: wounds with moderate to heavy drainage (traps moisture)

Hydrocolloid (DuoDERM):

• Waterproof, adhesive outer layer with a gel-forming inner layer
• Promotes moist healing
• Can stay in place for 3-7 days
• Best for: partial-thickness wounds, light to moderate drainage, Stage 2 pressure injuries
• Not for: infected wounds, wounds with heavy drainage

Foam (Mepilex, Allevyn):

• Absorbent, cushioning, non-adherent
• Comes in adhesive and non-adhesive varieties
• Can stay in place for 3-7 days
• Best for: moderate to heavy drainage, pressure injuries, under compression wraps
• Good for fragile skin because foam dressings are gentle to remove

Alginate (such as Kaltostat):

• Made from seaweed
• Very absorbent
• Forms a soft gel when it contacts wound fluid
• Best for: heavy drainage, deep wounds, packing material
• Not for: dry wounds (it needs moisture to work)

Hydrogel (Intrasite, SAF-Gel):

• Water-based gel that donates moisture to the wound
• Available as sheets, tubes, or impregnated gauze
• Best for: dry wounds, wounds with necrotic tissue (helps soften eschar), painful wounds (cooling effect)
• Not for: wounds with heavy drainage

Silver dressings:

• Contain antimicrobial silver
• Best for: wounds with confirmed or suspected infection, high-risk wounds
• Used as ordered by the physician or wound care nurse

Collagen dressings:

• Contain bovine or porcine collagen to promote cellular growth
• Best for: chronic wounds that have stalled in the healing process
• Used as ordered by the wound care team

Applying a Dressing, When Delegated

1. Use the dressing named in the care plan.
2. Cut the dressing to size. It should overlap the wound edges by at least 1 inch (2.5 cm) on all sides.
3. If packing a deep wound, moisten the packing material with saline and gently place it into the wound. Fill the dead space but do not pack tightly (tight packing increases pressure and impairs blood flow).
4. Apply the primary dressing (the one that contacts the wound).
5. Apply a secondary dressing (cover dressing) if needed. Secure with tape or a wrap.
6. Label the dressing with the date, time, and your initials.
7. Document the wound assessment and the dressing change.

Pressure Injuries

Pressure injuries are a common type of chronic wound. Keep the person off the injured area and follow the repositioning plan, because pressure stops healing.

Signs of Wound Infection

Report these signs to the nurse or physician immediately:

Local Signs of Infection

• Increasing redness spreading outward from the wound edges
• Increased swelling or induration around the wound
• Increased warmth to touch
• Purulent drainage (thick, opaque, yellow, green, or brown)
• Foul odor
• Increased pain at the wound site
• Wound bed changes from red to dark or gray
• Wound stopped progressing or is getting larger despite appropriate care
• New undermining or tunneling

Systemic Signs of Infection

• Fever (temperature above 100.4 degrees F / 38 degrees C)
• Chills
• Increased heart rate
• Red streaks spreading from the wound toward the heart. This is lymphangitis, an infection spreading through the lymph system. Report it immediately
• Confusion or altered mental status (especially in elderly patients)
• General malaise (feeling unwell)

When to Call Immediately

• Red streaks from the wound
• Fever with wound deterioration
• Foul-smelling, copious purulent drainage
• Rapid increase in wound size
• Patient becomes acutely confused or lethargic

Wound Care Documentation

When a dressing change is in your role, record the date and time, what you saw, how much drainage and what kind, the surrounding skin, the person's pain, what you used, how they tolerated it, whether it is better or worse, and who you told. A full wound assessment includes location, size, wound bed appearance, drainage, surrounding skin and pain.

What Is Usually Outside an Aide's Role

Rules vary, but these tasks usually belong to a nurse or wound care specialist:

• Sterile dressing changes and clinical wound assessment.
• Removing dead tissue (debridement).
• Packing deep or tunneling wounds.
• Using negative pressure wound therapy (a wound VAC).
• Choosing or changing a dressing type.

If a family member asks you to do one of these, explain that it is outside your role and call the nurse.

Common Mistakes

Check Your Understanding

1. A wound bed is beefy red and bumpy. Is that good or bad?

Good. That is granulation tissue, which is healthy.

2. A dressing you remove shows thin, clear, slightly yellow fluid. What is the word for this type of drainage?

Serous.

3. A client's skin at the edge of her dressing has turned pale, wrinkled and wet-looking. What might be going on?

That is maceration, caused by too much moisture. Report it, because the dressing plan may need to change.

4. A client's wound has spreading redness and now red streaks going up the leg. What do you do?

Report it right away. Red streaks can mean infection is spreading.

Key Takeaways

• Wounds heal in four phases, and the first redness and warmth can be normal.
• Red tissue is healthy, yellow is slough and black is dead tissue.
• Clean from the center outward with saline, and keep wounds moist.
• Dressings should overlap the wound by at least 1 inch.
• Report spreading redness, pus, odor, fever and red streaks.
• Follow your scope, and call the nurse.