Wound care and repair

Introduction

Open-wound injury comprises a significant component of the emergency department (ED) workload. Data from the Victorian Injury Surveillance System showed that 72% of all ED presentations for unintentional cutting and/or piercing injury that did not require admission were open wounds. In addition, open wounds may accompany other injuries, such as fractures. Of open wounds that occur in the home, 19% are in the paediatric age group (0 to 14 years), 62% occur in people under 35 years of age, and less than 10% are seen in the group above age 65. Overall, 65% of patients are male.

Location data show that more than 53% of these wounds occur in the home, mostly during activity described as leisure. The three major causes are falls up to 1 m, contact with cutting or piercing objects, or having been struck or collided with. Most are unintentional and only 3% are due to an assault. Injuries to the face, head and neck comprise

12% and the upper extremity is involved in 62%. Eighty-eight per cent of all presentations are repaired in the ED and the patient is discharged home. Almost half are referred to general practitioners (GPs) and specialists for review. Wounds suitable for ED repair are discussed further.

Clinical presentation

An initial general assessment of the patient is important, as it defines the likely mode of repair as well as the injured structures and identifies factors for complications. The assessment includes the traditional history, examination and investigation of the patient.

It is important in the history to identify the time and mechanism of injury, the likely presence of foreign bodies and the patient’s tetanus immunization status. Past medical history, allergies to agents—such as local anaesthetics, antibiotics, preparation solutions and tapes, and current medications such as warfarin or cytotoxics—all have a bearing on management. For example, there is a greater risk of infection and poor wound healing in diabetic patients with extremity wounds of the lower limbs sustained in a crush injury. Other relevant general conditions, particularly in the setting of dirty wounds such as bites, include prior mastectomy and other causes of chronic oedema of the affected region, prior splenectomy, liver dysfunction, immunosuppression or autoimmune disease, such as systemic lupus erythematosus (SLE). Smokers have impaired collagen production in healing wounds.

The general examination comprises a search for all injuries sustained and concurrent medical illness that may have a bearing on the results of repair, such as poor circulation in patients with peripheral vascular disease. The patient must be recumbent (beware of syncope) and any clothing that may obstruct a thorough examination must be removed. Constricting rings or other jewellery that encircle the injured body part should also be removed. A general examination is performed, followed by a local examination of the wound coupled with initial cleansing. Function and nerve or vessel injury are then looked for. A detailed examination of the depth of the wound, which usually requires good anaesthesia, is then performed. A surface wound caused by the entrance of a foreign body does not necessarily mean that the foreign body has remained in the vicinity. A decision is made regarding the requirement for further investigations, which include radiographs for fractures and some foreign bodies or ultrasound for radiolucent foreign bodies.

An injury to a tendon in the base of the wound may become apparent only when the joints over which it acts are in a particular position, reflecting the position of the limb at the time of injury. At other positions, the tendon injury may slide out of view. Marked pain with use may be a clue to a partial tendon injury.

Any tendon injury or other factors, such as nerve damage, indicate the need for referral to a plastic surgeon.

Wound cleansing

To provide optimum conditions for healing without infection, it is essential to remove all contaminants, foreign bodies and devitalized tissue prior to wound closure.

Universal precautions, including eye protection (goggles or similar), clothing protection (gown) and gloves, must be used for all wound care and repair. Gloves should be powder free to avoid adding starch as a foreign body to the wound, which will delay healing and produce granulomas. One must be aware of the risk of latex allergy to both the glove wearer and the patient.

If necessary, hair can be removed by clipping 1 to 2 cm above the skin with scissors. Shaving the area with a razor damages the hair follicle and is associated with an increased infection rate. Scalp wounds closed without prior hair removal heal with no increase in infection.

The skin surface should be cleansed using sterile normal saline. This has the lowest toxicity and there is no benefit in using antiseptic.

Recent studies have shown that the use of tap water in the cleansing of simple lacerations is as effective as normal saline.

A wide variety of cleansing solutions is available ( Table 3.10.1 ), with differing attributes.

Anaesthesia is necessary for wounds to be cleansed adequately. Extensive wounds, or particularly heavily contaminated wounds that need vigorous scrubbing, such as road debris tattooing, may require general anaesthesia. Local anaesthetic may be given by local infiltration or as a regional nerve block. Needles introduced through the wound cause less pain but may theoretically track bacteria into the tissues, although this has not been demonstrated to be a problem clinically. After anaesthesia, irrigation with a pressure of at least 8 psi (55 kPa) is required to dislodge bacteria and reduce the incidence of infection. This can be achieved with a 19-gauge needle, a 25- to 50-mL syringe, a three-way tap and a flask of fluid, such as sterile saline ( Fig. 3.10.1 ). High-pressure irrigation (>20 psi, 138 kPa) may cause tissue damage.

Radiopaque foreign bodies—such as gravel, metal, pencil lead and glass greater than 2 mm in size —may be identified using x-rays. A radiopaque marker, such as a paper clip, can be placed at the wound to help identify the position of the foreign body. This is not sensitive for plastic or wood, however, which may be detectable with ultrasound if larger than 2.5 mm. However, if there is gas due to an open wound, this will make ultrasound less sensitive.

Adequate debridement of devitalized tissue has always been a tenet of surgical practice. More recently, there has been a change in emphasis from radical to meticulous debridement. If the skin is devitalized, it should be removed using a scalpel blade. Viable tissue will bleed when cut and viable muscle will contract when stimulated. If viability is in doubt, it may be better to wait for demarcation over the following days with regular close observation. Fat and fascia are relatively avascular; if they are semi-viable in contaminated wounds, they should be removed. Semi-viable muscle can usually be preserved when it is well drained. Nerves, major vessels and tendons should not be debrided in the ED. Lavage and debridement should be continued until the wound is clean. Organic material and anionic soils, such as clay, pose the greatest risk of infection if not removed. The highly charged clay particles directly affect leucocytes, preventing phagocytosis of bacteria. They also react chemically with antibiotics, limiting their action.

Once the wound is clean, the decision to close immediately or later is made.

Guidelines for delayed closure may include the following:

• Puncture wounds, such as made with a tooth or a knife

• Wounds that cannot be adequately debrided

• Contaminated wounds more than 6 hours old

• Too much tension in the wound, particularly with crush injury

In some cases, such as thoroughly lavaged puncture wounds, it may be prudent to allow healing by secondary intention. If in doubt, consult with a plastic surgeon. When repair in the ED may be delayed, it is prudent to have nursing staff perform a preliminary preparation of the wound along the lines shown in Box 3.10.1 .

Antibiotics are necessary only in wounds involving joints, tendons, nerves, vessels, significant crush injury or if they are due to human or animal bites.

Tetanus prophylaxis

The risk of tetanus is greatest in the very young and the very old, with an overall death rate of 1:10 in Australia, so prevention is all-important. An average of 10 cases per year occur in Australia, usually in older adults who have not been immunized or who have allowed immunization to lapse. The anaerobic bacterium Clostridium tetani is present in soil and animal faeces. After incubation of 3 to 21 days following inoculation into a wound, the toxin produced by the bacteria causes severe muscle spasm and convulsions. Death occurs commonly as a result of respiratory failure. The types of wound at risk are listed in Box 3.10.2 , but tetanus may occur after apparently trivial wounds.

Tetanus immunoglobulin is given into the opposite limb to the tetanus toxoid in patients with inadequate protection against tetanus ( Table 3.10.2 ), thus providing passive protection.