Wounds & Wound Management Overview

Wounds & Wound Management

• Wounds are breaks in tissue continuity, caused by injuries or operations, potentially disrupting structure and function.
• Wound healing follows a specific sequence of overlapping phases: inflammatory, proliferative, and remodeling/maturation.
• The inflammatory phase (days 0-5) is characterized by heat, swelling, redness, pain, and loss of function at the wound site. This is a short-lived process.
• The proliferative phase involves fibroblasts, endothelial cells, and epithelial cells working together to build granulation tissue to fill the wound.
• The maturation/remodeling phase involves collagen deposition. Collagen III is initially laid down, gradually decreasing over time, with collagen I increasing to strengthen the wound. Remodeling continues for about a year, but the wound won't necessarily reach its original tensile strength.
• Wound contraction is important: special myofibroblasts start immediately and continue for the next 2–3 weeks, shrinking the wound size.
• Factors affecting wound healing are categorized as general and local.

Factors Affecting Wound Healing

• General factors include:

  • Age: slower healing in elderly due to reduced protein turnover.
  • Debilitating diseases (e.g., uremia, jaundice, cirrhosis, diabetes, malignancy): hindering healing.
  • Irradiation: preventing wound contraction and granulation tissue from forming, potentially leading to ischemia due to end arteritis obliterans.
  • Nutrition: proteins for collagen synthesis, vitamin C for procollagen maturation, and vitamins A, calcium, zinc, copper, and manganese for epithelialization.
  • Drug intake like steroids, which inhibit inflammatory response and fibroblast formation.

• Local factors include:

  • Vascularity: good blood supply aids rapid healing, while poor supply (e.g., below the knee) delays healing. Immobilization (wounds over joints or weight-bearing areas) can impact healing.
  • Tension: sutures under tension, or hematoma, increasing wound tension leads to ischemia and delayed healing.
  • Infection: bacteria compete with fibroblasts for oxygen and nutrients, and produce collagen-destroying enzymes.
  • Foreign bodies and necrotic tissue: hamper healing.
  • Adhesion to a bony surface prevents wound contraction (e.g., over the shin of the tibia, leading to chronic venous ulcers).

Classification of Wounds

• Based on Rank and Wakefield classification:
  • Tidy wounds: surgical incisions, sharp object wounds. Suturing is typical and healing is by primary intention.
  • Untidy wounds: crushing, tearing, avulsion, devitalized injury, vascular injury, multiple irregular wounds, burns. Fractures of underlying bones may be present; often associated with dehiscence, infection, and delayed healing.

Types of Wounds

• Types of wounds are categorized into closed and open wounds.

  • Closed wounds include contusions and hematomas.

  • Open wounds include incised, lacerated, penetrating, missile wounds, and bites.

• Specific open wound types include:

  • Contusions: blunt force trauma, capillary bleeding, causing bluish/brownish discoloration
  • Hematomas: excessive bleeding, clot formation, potentially needing absorption, organization through fibrosis, or liquefaction.
  • Abrasions: superficial skin scraping, often painful, requiring cleaning and non-adherent dressings.
  • Incised wounds: sharp instruments, longer than deep, clean cuts potentially involving tendons and nerves.
  • Lacerated wounds: blunt trauma, irregular shapes, severely traumatized, devascularized, potentially contaminated, and often include degloving injuries
  • Penetrating wounds: pointed objects with deeper injury extent, potentially involving vital structures and increasing infection risk.
  • Missile wounds: projectile penetration impacting healing.
  • Bites: animal or human bites potentially involving bones, joints, tendons, vessels, nerves; high infection risk in puncture wounds.

Wound Healing Intentions

• Primary intention: clean wounds closed immediately (sutures or clips). Minimal scar.
• Secondary intention: edges not approximated, due to hematoma or infection; wound filling with granulation tissue; results in an ugly scar.
• Tertiary intention: contaminated wounds left open initially; after about 5 days, if there are no signs of infection, sutures are used.

Classifying Wounds

• Wounds can be classified by the depth of tissue involvement (superficial, partial-thickness, full-thickness).
• Classification of surgical wounds into clean, clean-contaminated, contaminated, and dirty infected and their associated infection rates.

Management of Open Wounds

• Bleeding control: direct pressure; avoid tourniquet, unless temporary.

• Suspected fractures: splinting, X-rays.

• Thorough cleaning: saline irrigation, foreign body removal, followed by antiseptic solutions (e.g., povidone iodine).

• Inspection of all structures in the wound and dealing with issues.

• Arteries and veins: ligated if small; repaired if large

• Nerves and tendons: repaired

• Muscles: repaired using mattress sutures, or removed if ischemic or necrotic.

• Bones: no internal fixation in high infection risk, but external fixation if necessary. Deep fascia usually left open in extensive wounds.

Complications of Wounds

• General complications: shock, crush syndrome, compartment syndrome.

• Local complications: infection (pyogenic or specific), gangrene (vascular or infective), and healing complications (dehiscence, evisceration, scar stretching/contracture, keloid).

Complications of Wound Healing

• Dehiscence: partial or total wound separation, especially in abdominal wounds (burst abdomen).
• Evisceration: wound layers separate, organs protrude.
• Scar stretching/contracture: scar tissue shortens.
• Keloid: excessive scar tissue beyond the original wound. Hypertrophic Scar: overgrowth limited to the scar tissue, but does not extends beyond the wound.