Wilderness and Rescue Medicine 7th Edition Jeffrey Isaac, PA-C and David E. Johnson, MD

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Wilderness and Rescue Medicine

infection. They can be managed in the field, with evacuation to medical care as convenient.

Wounds Problems begin when the protective outer layer of skin is damaged and the soft tissue beneath is exposed. This allows microbes to invade unpro- tected tissue and lets body fluids escape. Deep wounds where the fascia is interrupted are at high- risk for infection. Extensive soft-tissue injury can cause shock and hypothermia. All wounds damage blood vessels and cause bleeding. The body attempts to control blood loss by automatically constricting blood vessels at the injury site. Chemical components called clotting factors interact with platelets in the blood to form a blood clot. Under most circumstances, bleeding will stop within 15 minutes. Sometimes it needs a little help in the form of direct pressure or other bleeding control techniques. After the blood loss has been stopped, the slower process of wound repair begins. The initial stages of natural wound cleansing occur over a period of several days. The clot surface dries, forming a natural bandage in the form of a scab. Underlying tissue is further protected by the process of inflam- mation that provides a protective barrier beneath the injury. Contaminants like dirt and bacteria are flushed out as the wound drains. By the third or fourth day, the protective barriers are established, and cleansing is well underway. Redness, warmth, swelling, and pain begin to decrease as the normal inflammatory response subsides. After 6 to 10 days, the wound is very resistant to contamination. Wound edges migrate together as the collagen fibers within the clot contract. Scar formation and complete healing continue over the next 6 to 12 months. Wound Assessment There are many terms—such as laceration (slice), avulsion (skin flap or tissue removed), and abra- sion (scuff or rubbed off)—used to describe wounds. For field purposes, wounds can be assessed generically as low risk or high risk. Simple low risk wounds offer no risk of life-threatening bleeding and do not represent a significant risk of

General Principles

Wound Assessment

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• Low Risk (simple) • Cosmetic or Functional Risk • High Risk Wilderness Perspective

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Low Risk Wounds Low risk wounds may involve the dermis and subcutaneous fat, but they do not penetrate the fascia. There is no contamination of muscle, bone, tendon, or joint structure. These wounds are clean and free of devitalized or macerated tissue. A superficial cut from a clean knife is an example.

General Principles

Wound Assessment

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Low Risk (simple): • Dermis and subcutaneous fat only • Clean, straight, no devitalized tissue • Low risk of infection

“A superficial cut from a clean knife is an example.”

©2018WMA

Some wounds have the potential to cause cos- metic or functional defects as they heal. Examples include wounds of the face, hands, and genitalia. You may choose to refer these wounds for imme- diate care when the risk of evacuation is low. The best results will be obtained when wound repair is accomplished within several hours, but acceptable wound repair can be accomplished days later, if necessary.