Lecture 3: Wound Healing Part 1

Wound Care

Introduction to Wound Healing

• Presented by Morgan Cummings, PT, DPT, GCS

Objectives

• Review the anatomy and physiology of the Integumentary System

• Identify stages of wound healing

• Differentiate between normal and abnormal wound healing

• Identify signs and symptoms of wound infection

• Discuss PT interventions to promote wound healing

Review of the Integumentary System

Skin Facts

• Largest organ in the human body

• Approximately 300 million skin cells on average

• Cells replaced roughly every 28 days

• Skin thickness: 0.2 mm (eyelids) to 1.4 mm (feet)

• At least 5 types of receptors for pain and touch

Skin Functions

• Protection

• Sensation

• Regulating body heat (insulation and secretion)

• Prevention of fluid loss and gain

• Vitamin D synthesis

• Aesthetic appearance

Anatomy of the Skin

• Composes of various structures:

  • Epidermis

  • Dermis

  • Subcutaneous Tissue

  • Capillaries

  • Sweat Glands

  • Hair

  • Sebaceous Glands

  • Sensory Nerve Ending

Epidermis

• Composed of 5 layers:

  • Stratum corneum

  • Stratum lucidum

  • Stratum granulosum

  • Stratum spinosum

  • Stratum basale

• Role: primary protection

• Avascular, composed of epithelial cells (keratinocytes)

Dermis

• Divided into 2 layers:

  • Papillary dermis

  • Reticular dermis

• Role:

  • Sensation (contains mechanoreceptors, thermoreceptors)

  • Secretion (contains appendages like hair follicles)

  • Protection (contains leukocytes)

• Highly vascular and made of connective tissues (collagen and elastin)

Basement Membrane and Hypodermis

• Basement Membrane:

  • Made of extracellular matrix, providing support and attachment to other layers.

• Hypodermis (Subcutaneous Layer):

  • Composed of loose connective and adipose tissue.

  • Highly vascular.

  • Functions:

    • Protection (cushioning)

    • Assists in thermoregulation

    • Stores energy and fat-soluble vitamins

    • Supports the dermis

• Deeper Structures: include muscles, ligaments, tendons, bones.

Wound Healing

Wound Closure Types

• Primary Intention:

  • Surgical closure; heals in about 7 days.

  • Accelerated healing but still passes through healing phases.

• Secondary Intention:

  • Wound heals through 4 phases; acute wounds can close in 3-4 weeks, chronic wounds take much longer.

  • Wound dehiscence refers to reopening of a surgical wound left to heal via secondary intention.

• Tertiary Intention:

  • Contaminated wounds left open for cleansing and later closed surgically.

Phases of Wound Healing

1. Hemostasis: Goal is to stop bleeding; occurs immediately after injury.

2. Inflammation: Creates a clean wound bed; occurs from day of injury to day 10.

3. Proliferation: Aims to close the wound bed; occurs from day 3 to week 2-3.

4. Maturation (Remodeling): Focused on full wound closure and forming scar tissue; occurs from day 9 to >2 years.

Factors Affecting Wound Healing

Wound-Specific Factors

• Mechanism of onset

• Time since onset

• Location and dimensions of the wound

• Temperature and hydration of the wound

• Presence of necrotic tissue/foreign bodies

• Infection and inappropriate wound care (compliance issues and dressing types)

Systemic Factors

• Lifestyle:

  • Smoking, alcohol use, stress

  • Nutrition:** Essential nutrients include iron, vitamin B12, vitamin C, zinc, protein.

• Comorbidities:

  • Peripheral vascular disease, diabetes, immunocompromised conditions.

• Age:

  • All phases of healing can be slowed with age.

External Factors

• Pressure, shear, and friction can impair healing.

Abnormal Wound Healing

• Wounds can become stuck in any phase, causing different characteristics:

  • Chronic inflammation

  • Hypergranulation (during proliferation)

  • Hypogranulation and delayed re-epithelialization (during maturation)

  • Epibole (rolled edges)

  • Dehiscence (insufficient tensile strength of scar tissue)

  • Formation of hypertrophic scars or keloids.

• Chronic wounds do not heal within six weeks under optimal conditions.

Infection

Continuum of Wound Infection

• Contamination: presence of microorganisms that do not impact healing.

• Colonization: microorganisms successfully replicate without affecting healing.

• Infection: microorganisms proliferate, overwhelming the immune system and impacting healing:

  • Local infections stay within wound boundaries.

  • Spreading infections extend beyond the wound perimeter.

  • Systemic infections can lead to severe outcomes like sepsis.

Preventing Infection

• Universal Precautions: mandatory hand washing for all patients.

• Standard Precautions: used for suspected infections; includes gloves and hygiene practices.

• Sterile vs. Clean Techniques:

  • Clean techniques are standard for typical wounds.

  • Sterile techniques used for high-risk patients.

Signs & Symptoms of Infection

• Local Symptoms:

  • Erythema, warmth, edema, increased exudate.

  • Subtle signs include undermining, hypergranulation, and new pain.

• Spreading Symptoms:

  • Fever, confusion, elevated white blood cell counts, malaise.

• Silent Infections: hard to detect in immunocompromised patients due to lack of classic signs.

Diagnosing Infection

• Wound culture, tissue biopsy, blood tests, fluid aspiration.

Managing Infection

• Antimicrobial Therapy: using impregnated dressings (silver, honey), topical agents, systemic antibiotics.

• Antiseptic therapy: includes hand hygiene and specific antiseptics.

• Debridement: necessary for removing infected or necrotic tissue.

Assessment & Treatment of Wounds

• Further discussion to occur in lab settings.