Chapter 9. Evaluating and Preparing Wounds

Traumatic wounds are regularly encountered in the emergency department. It is important to document important historical information such as the mechanism, timing, and location of injury, and the degree of contamination. Associated symptoms of pain, swelling, paresthesias, and loss of function should be identified. Ascertain factors that affect wound healing, such as the patient's age, location of injury, medications, chronic medical conditions (eg, diabetes, chronic renal failure, or immunosuppression), and previous scar formation (keloid). Patients with the sensation of a foreign body are much more likely to have retained a foreign body. Patient characteristics of handedness, occupation, tetanus status, and allergies (eg, to analgesics, anesthetics, antibiotics, or latex) should be documented. When caring for wounds, the ultimate goal is to restore the physical integrity and function of the injured tissue without infection.

When treating a wound, consider the time, mechanism of injury, and its location because these factors play a role in the potential for infection. Shear, compressive, or tensile forces cause acute traumatic wounds. Shear forces are produced by sharp objects with relatively low energy, resulting in a wound with a straight edge and little contamination that can be expected to heal with a good result. Wounds caused by compression forces crush the skin against underlying bone. These high-energy forces produce stellate lacerations. Tension forces produce flap-type lacerations. These wounds typically have surrounding devitalized tissue and result in a wound much more susceptible to infection than those caused by shear forces.

Assessment of a wound's potential for infection is vital. Predictive factors for infection include location, depth, characteristics, contamination, and patient age. The risk of infection relates to the interaction of bacterial contamination, time to wound closure, and blood supply. The density of bacteria is quite low over the trunk and proximal arms and legs. Moist areas such as the axilla, perineum, and exposed hands and feet have a higher degree of colonization.

Wounds of the oral cavity are heavily contaminated with facultative and anaerobic organisms. Wounds sustained from contaminated objects or environments and animal and human bites have an increased infection risk. Wounds contaminated with feces have a high risk of infection despite determined therapy. Over the first 24 hours, the longer the time from injury to wound closure, the greater the risk of infection. Wounds in highly vascular areas such as the face and scalp are less likely to become infected.

Wound examination is greatly facilitated by a cooperative patient, good positioning, optimal lighting, and little or no bleeding. Universal precautions should be used during evaluation. A thorough and compulsory examination will minimize the risk of missed foreign bodies, tendon, and nerve injuries, a common cause of litigation.

Documentation of a wound should include the location, size, shape, margins, and depth. Pay particular attention to sensory, motor, tendon, vascular compromise, and injuries to specialized structures. Blood pressure differences between injured and noninjured extremities will help identify significant arterial injuries. Careful palpation and inspection of the wound and surrounding area may show the presence of a foreign body or bony injury. Consider injecting joints with overlying wounds to identify violation of the joint space.

Proper wound preparation is the most important step for adequate evaluation of the wound, to restore the integrity and function of the injured tissue, prevent infection, and maximize cosmetic results.

Full sterile technique has not been shown to reduce infection after repair. Clean, nonsterile gloves and attention to cleanliness may be used to improve efficiency and cost savings.

1. Control pain with local or regional anesthesia before any wound manipulation (see Chapter 7). This will enable better preparation and evaluation of the wound and a more relaxed, cooperative patient.

2. Perform a careful neurovascular examination of the involved and distal area before anesthesia. Two-point discrimination (< 6mm) will help identify digital nerve injury.

1. Control of bleeding is necessary for proper wound evaluation and treatment.

2. Direct pressure is the preferred method and is usually effective.

3. Epinephrine containing local anesthetics are safe for digital nerve blocks, nose, and ears except in patients with underlying small vessel disease.

4. Ligation of minor vessels in the extremity may be necessary and can be achieved by applying an absorbable suture material after isolating and clamping the involved vessel.

5. Other means of hemostasis can be used, such as applying pressure with gelatin, cellulose, or collagen sponges placed directly into the wound (eg, Gelfoam®, Oxycel®, Actifoam®).

6. Cautery, with a bipolar device for vessels <2 mm and battery powered device for capillaries, can be used to control extensive bleeding.

7. Finger tourniquets or pressure cuff proximal to the injury and inflated above the systolic blood pressure will control bleeding. Their duration should be minimized.

1. Visual inspect the full depth and course of all wounds for foreign bodies (see Chapter 14).

2. Remove hair, which can act as a foreign body, by clipping 1 to 2 mm above the skin with scissors. Shaving may damage the hair follicles, allowing bacterial invasion, and can increase the infection rate by 10 fold. Ointment can be applied to the hair roots to keep hair away from wound edges.

3. Do not remove hair from the eyebrows due to the potential for abnormal or lack of regrowth.

4. Most foreign bodies and glass shards ≥2 mm will be detected by routine radiographs. Foreign bodies with densities similar to those of soft tissue may require the use of computed tomography, magnetic resonance imaging, or ultrasound (see Chapter 14).

1. Wound irrigation reduces the risk of infection.

2. Use low pressure irrigation (0.5 psi) with a slow, gentle wash for uncontaminated wounds and loose tissues.

3. Use high pressure irrigation (≥7 psi) with an 18 gauge catheter and syringe for contaminated wounds.

4. Irrigate contaminated wounds until all visible debris is removed.

5. Consider anesthesia before irrigation.

6. Wound soaking is not effective in cleaning contaminated wounds and may increase wound bacterial counts.

7. Although sterile normal saline solution has the lowest toxicity, tap water is safe and effective. There is no added benefit to the addition of povidone iodine or hydrogen peroxide to irrigation fluid.

1. Devitalized tissue may increase the risk of infection and delay healing. Debridement removes foreign matter, bacteria, and devitalized tissue and creates a sharp wound edge that is easier to repair.

2. Elliptical excision around the wound edges with a standard surgical blade is the most effective type of debridement. Tissue that has a narrow base or lacks capillary refill will require debridement.

3. Wounds with an extensive amount of nonviable tissue may require a large amount of tissue removal and will need more delayed wound closure or grafting. In general, a surgical specialist should be consulted to manage these wounds.

Although there is no clear evidence that antibiotic prophylaxis prevents wound infection in most emergency department patients, there may be a role in selected high-risk wounds and populations.

1. When used, antibiotic prophylaxis should be (a) started rapidly, before significant tissue manipulation; (b) performed with agents that are effective against predicted pathogens; and (c) administered by routes that rapidly achieve desired blood levels. Oral antibiotics may be as effective as intravenous if the agent has sufficient spectrum of coverage and rapid absorption.

2. Most non-bite infections are caused by staphylococci or streptococci and coverage with a β-lactam is reasonable. Use a first generation cephalosporin cephalexin 25 to 50 milligrams/kilogram/day PO 4 times per day in children; 500 milligrams PO four times per day in adults. For β-lactam allergic patients, use clindamycin 8 to 25 milligrams/kilogram/day 3 times per day in children or 150 to 450 four times per day for adults.

3. Treat patients with human and mammalian bites with amoxicillin-clavulanate 25 to 50 milligrams/kilogram/day twice per day in children, 875 milligrams PO twice per day in adults for Pasteurella, Eikenella, or Capnocytophaga (see Chapter 15).

4. Effectiveness of antibiotics for oral lacerations is inconclusive. If you chose to cover with antibiotics, use penicillin 25 to 50 milligrams/kilogram/day PO divided over 3 doses per day; 500 milligrams PO 3 times daily in adults.

5. Prescribe ciprofloxin 500 PO twice each day in adults with wounds contaminated by fresh water and plantar puncture wounds to cover for Pseudomonas.

6. Duration of prophylactic antibiotics is 3 to 5 days for non-bite wounds and 5 to 7 days for bite wounds.