6. Minor wounds and burns
Contents
Initial presentation with wounds173
Assessment and exploration of wounds178
Wound infection182
Wound treatment185
Special types of wound195
Minor burns199
Initial presentation with wounds
Assessment
Patients with superficial wounds often believe that their injuries are more serious than they are. They may also underestimate certain wounds, for instance where there is painless damage to tendons or where there is the potential for a vigorous infection. This probably owes much to the different impressions created by the frightening, visible aspect of a wound, the torn skin and the blood, and its quiet depths. Nevertheless, serious injuries are usually obvious, from the history of a severe mechanism, from the evidence of the wound itself and from the shocked appearance of the patient. It is not common to find a patient sitting quietly in the waiting area of a minor injury clinic with an unannounced, life-threatening wound. There are, however, some situations where you will give an urgent priority to the patient.
Wounds to the head
Many patients with wounds to face and head have superficial and easily treated injuries. However, the neurological situation should always be assessed before the wound is dealt with. If a patient is bleeding from the canal of the ear or from the nose (or if there is a discharge of pale fluid which tests positive to sugar on a urinalysis stick) after a blow to the head, the differential diagnosis includes fracture of the base of the skull. Consider the possibility of a depressed skull fracture with scalp lacerations, especially where the history is of blunt injury, where there are indications of neurological disturbance in the history or the examination, where there is a large haematoma, or where the bone surface does not feel smooth. Full-thickness scalp lacerations may need closure in layers.
Do not forget to assess sensory and motor function in the forehead and face when a wound is present.
Penetrating Wounds
Any patient with a penetrating wound, or any wound where the base of the lesion cannot be seen, over the neck, chest or abdomen is a potential emergency even if the patient seems uncompromised. The patient should be assessed for resuscitation (ABC: airways, breathing, circulation) and vital signs recorded. Transfer the patient to the appropriate specialist. Surgical exploration of the injury may be required.
Potential HIV infection
If a patient has just suffered a needlestick injury or a human bite and there is a possibility that HIV (human immunodeficiency virus) prophylaxis will be given, treatment is time critical. Local policies are in place throughout the UK. Contact the responsible specialist in your area. Combine that with immediate cleaning of the injury, encouraging it to bleed and irrigating it with copious amounts of running water. In practice, given the common hazards which accompany human bites – tendon and joint injuries, hepatitis B and C infection, aerobic and anaerobic bacterial infections, as well as the risk of HIV – there is always a low threshold for referral of such patients to a doctor.
Initial problems
A patient will usually have a minor wound under control when arriving at the clinic. There will be a rough pressure dressing on the wound, controlling the bleeding and reducing the pain. The patient will not be likely to faint if the dressing is not touched. Do not expose the injury in a waiting area. Bystanders will not be pleased to be given the chance to see or be splashed by blood. The nature of the wound will be hard to predict from the appearance of the dressing and you should prepare to manage bleeding before removing it. Bring the patient to a treatment area and let him lie down on a trolley.
Bleeding
Bleeding will stop if some swabs are put over the wound and direct pressure is applied with a gloved hand. In the case of a limb wound, elevation will reduce the flow of blood. A few minutes are enough to stop an ordinary venous bleed in a small wound. If an artery is divided the bleeding will be pulsing and spurting in contrast to the oozing nature of venous bleeding. This will require more prolonged pressure to stop it, and it may alter the plan for managing the wound. Assess perfusion beyond the injury. Is there good colour and warmth, are pulses present, is capillary refill time normal equal to the other limb? How much blood has the patient lost? Are there signs of low circulating blood volume? Is he pale and tachycardic, has his blood pressure fallen? Arterial bleeding will usually stop with direct pressure, but it may be necessary to maintain pressure for a long time. Small but persistent bleeding arteries are sometimes tied off. On rare occasions the problem may require surgical intervention.
Bleeding is a factor throughout the treatment of a wound, and it can make exploration and closure difficult. With a hand wound, elevating the bleeding part often solves the problem. Adrenaline can be introduced into some wounds along with local anaesthetic to cause vasoconstriction, but it must not be used in wounds to peripheral parts such as fingers, where it may cause ischaemia. Tourniquets of various kinds can also be used but do not embark on this if you have no support or training. It should be done with great care to avoid injury to vessels and ischaemia. Time the use of the tourniquet and above all, do not forget to remove it. If you are working in a minor area without medical support, and you are having difficulty managing bleeding, it is probably an indication that the patient should be referred on for a more formal exploration of the wound. Where one deep structure is injured, there is probably justification in worrying about other ones. When bleeding is a problem, satisfactory assessment of the other structures which might be injured is difficult. Bleeding is a distressing experience for the patient, and it will become so for you too if you do not manage it well.
If there is heavy bleeding and glass or metal can be seen in the wound, do not remove the object, press on it or otherwise disturb it. Put swabs around the object and apply pressure proximal to it.
Pain
A patient with a minor wound does not usually complain of pain until the wound is examined. Any pain which is caused during examination will settle if treatment is completed rapidly.
The key to a comfortable exploration of a wound is adequate anaesthesia.
In a minor injury clinic, many patients have small, superficial wounds (1cm or less), which are painful to treat but which have a tiny risk of complications. The patient’s reason for coming is that ‘it wouldn’t stop bleeding’. (Usually, by then, it has stopped, and it starts again when it is examined.) It is unpleasant to receive a local anaesthetic, and, in some sites such as the hand, it can be as painful as the treatment. It is, therefore, reasonable to ask the patient to put up with the discomfort if you are sure that a small flap wound will be cleaned, explored and closed with Steri-Strips in a matter of a minute or two.
If the wound is not complicated by any injury to deep structures, but needs suture (wounds with a Stanley knife to the fatty tissue of the thigh are a common example), a local anaesthetic is necessary and there is no point in cleaning or exploring the wound before it is given.
In almost every circumstance, where a wound will require opening, cleaning, exploration and closure, local anaesthetic should be used at the outset. The smallest disturbance of a wound is very painful. Cleaning and exploration have to be carried out patiently and thoroughly, and you must feel that the patient is comfortable and you are at liberty to do your job properly.
The time factor
The treatment of wounds, especially in cases where closure is an option, is time critical. Details of management are given below. The management of problems such as infection and deep structure injury is hampered if the wound is closed before those possibilities have been fully considered. Inappropriate closure of a wound may cause the patient harm. These factors mean that a patient with a wound requires management which is both prompt and accurate (in contrast, for example, to a sprain, where full assessment might be deferred until it is easier). If there is any doubt about a wound, the patient should be referred at once.
Faint
If it takes a few minutes to clean, explore and close a small hand wound, the patient is likely to feel faint. Always settle a patient with a wound comfortably on a trolley. Some patients are happy to lie flat while you work on the injury. Others resist this. Do not assume that a patient who sits up and watches everything you are doing will not faint. Watch the patient and make sure the backrest can be reached easily. Patients become pale before they faint. If patients lie down at this stage, they will soon feel better. Relatives in the treatment room may also faint.
Blood-borne infection
A wound is a potential hazard to any health worker who comes into contact with it because of the risk of blood-borne infection.
You run the risk of contracting hepatitis B, C and HIV. You are treating a stranger with a wound, in a setting where only what the patient chooses to tell about his medical history is known. This means that you must be rigorous in your precautions against contact with the patient’s body fluids. The patient may also have concerns in this situation. You work in a high-risk environment, and the patient is entitled to know that there is also protection from you, the person who is touching his bleeding wound. Always use gloves and other available equipment such as visors when they are appropriate.
Occupational health departments have policies for staff protection, covering a variety of matters such as protective equipment, immunisations against hepatitis B, the cleaning up of contaminated spillage, and needlestick injuries.
Definition of a minor wound
A wound is a break in the skin. Wounds occur under many circumstances and require different responses. The wounds which concern us here are those caused by trauma.
Types of wound
A traumatic wound can be one of several types. The distinctions between them are important for assessment and treatment. Describe the wound accurately in the notes. The following terms are used to describe wounds.
Cut
A cut is a break which has been incised into the skin by something with a sharp edge such as a knife, razor blade or glass. These wounds look neat and tend to be relatively easy to close. The main concern with cuts is the ease with which soft deep structures like nerves, tendons and blood vessels may be divided.
Laceration
A laceration is a break in the skin caused by blunt force. The skin has been burst rather than cut. These occur only on certain body sites where there is little padding between skin and bone, such as the top of the head or the back of the hand. Essentially the injured soft tissue has been crushed between two hard surfaces. A laceration will look more ragged than an incised wound. It may be contused (bruised). Blunt violence may complicate treatment. There may be brain injury or damage to any vital organ; there may be fracture. Swelling causes pain and compromises distal parts and makes suture inadvisable. Dirt and devitalised tissue carries a high risk of infection.
Penetrating wound
A penetrating wound is caused by something long, pointed and narrow. The term puncture is often used to describe penetrating wounds on the hand or sole of foot caused by nails, garden rakes or fence spikes. A penetrating wound looks like the least of wounds. The lurid, superficial signs are usually absent. There may be no external bleeding or bruising, and only the tiniest break in the skin.
• A body system for protection from heat, injury, trauma and infection. It regulates temperature through blood supply and sweat glands and has a large supply of sensory nerves. It is supported at below by layers of fascia.
• All layers are present everywhere but thickness varies with body site, age and health. Most skin 1–2mm thick. Skin on back can be 4mm.
• For wound closure the skin layers must be aligned, epidermis, dermis, superficial fascia (subcutaneous or subcuticular layer) and deep fascia.
• Epidermis (or cutaneous layer) is the outer protective skin layer. It has squamous epithelial cells. It has no vessels or nerves. It allows the release of water and salts. It is only a few cells thick and can’t be seen separately from dermis during repair. It aligns if the wound edges are matched. Its base layer, the stratum germinatavum, provides cells to repair injured epidermis. The stratum corneum is the keratinised outer layer.
• The dermis is below epidermis. It is much thicker, made of connective tissue, mainly fibroblasts, which builds collagen, the main component of connective tissue. It also contains macrophages, mast cells and lymphocytes, and these are active during healing. It has two layers, the papillary, which nourishes the epidermis, and the reticular, which contains blood vessels and hair follicles. Nerve endings are found in both layers. Dermis is visible and is the key structure for accurate wound repair. All sutures, superficial and deep, should be anchored in dermis. If it is damaged it should be debrided, but only the unsaveable tissue. The aim is to minimise scarring.
• Below dermis is the fatty layer of subcutaneous superficial fascia. It provides insulation and padding against injury. It can harbour clots and dirt and grow infection if devitalised. It can be debrided freely. It has the risk of creating dead space. Sensory nerves pass through it to dermis and local anaesthetic should be injected between superficial fascia and dermis.
• Deep fascia is a dense fibrous base for superficial fascia, and it is also wrapped around muscle in layers. It separates structures and helps to isolate infection. If it is divided it should be closed.
The problem is that the base of a wound cannot be seen. It is impossible to assess the damage, see any foreign matter or achieve a satisfactory wound toilet. A penetrating wound over a vital area should be treated as serious until proven otherwise. Even when a vital organ is not threatened, there is a potential for tetanus and gangrene. There may also be penetration of tendon sheath, joint capsule or bone.
Abrasion
An abrasion is a graze, an injury caused by friction shearing the skin away. It is usually a combination of superficial and partial thickness trauma, but a severe mechanism can produce a much deeper wound. There is usually what Glasgow & Graham (1997) call a ‘halo of inflammation’ around the overtly damaged skin in superficial injuries. Abrasions are common in patients who have fallen off bicycles.
Minor abrasions can be as painful as a superficial burn. Unfortunately, they are often very dirty, with embedded grit, mud and burned-in discolouration in an area of raw tissue. It is vital to clean an abrasion properly for two reasons. The first is infection. The second is a cosmetic problem. New skin which forms over superficial dirt will preserve it but not hide it, and the patient will have a permanent tattoo. Cleaning may require the use of inhaled nitrous oxide, local anaesthetic (either infiltrated or applied topically) and a nail or toothbrush. Children with grazes may need to be referred for surgical management. A large abrasion may take a long time to clean, but stick at it. It is important to do a good job.
When is a wound minor?
You may regard a wound as minor if it presents no complications which oblige a referral of the patient to a doctor. Such complications may include problems with exploration; cleaning or closure of the wound; concern about the size, depth or site of the wound; or mechanism of wounding, such as extreme violence or a human bite. Some complicating factors of wounds will now be discussed.
Factors which complicate wound management
Special types of wound are discussed later in this chapter. A main feature of a traumatic wound, compared with a surgical incision, or even with a pressure sore, is the amount that is unknown, uncontrolled and variable about the cause. This means that the priority of management, and the source of most of the problems, is not the closure or the dressing of the wound but the assessment of a range of risk factors which attend the injury. These factors are different from one patient to another. The history and, in particular, the mechanism of injury are the best guides to the possible hazards in any case.
• Inflammation – fibrinogen aids coagulation, platelets release growth factor, phagocytes remove debris.
• New circulation and lymphatic vessels start granulation.
• Epithelial cells grow over the wound from its edges.
• Fibroblasts and collagen fibres appear and the process becomes organised.
• Fibrous tissue matures into the final scar.
• At 1 week the wound has < 10% of original tissue strength.
• At 6 weeks most of the strength has been regained.
• At 1 year the tissue is < 80% of original strength.
• Children heal faster than adults.
• Initial appearance of a wound gives little clue as to the final outcome. It may improve, or there may be an undesirable appearance caused by contraction of the scar.
• Black skin may lose pigmentation for up to a year, and Afro-Caribbeans can develop keloid scars.
• Healed skin may burn more easily in the sun for a year.
Fractures
Injury to bone can occur with blunt trauma, giving rise to an open or compound fracture. In crush injuries, the wound may be dirty and the fracture comminuted. There is a risk of bone or joint infection.
Infection
The risk of infection is increased by the presence of dirt, devitalised tissue and haematoma and by a delay in treatment. Puncture wounds and human and animal bites carry risks which will be described below.
Foreign bodies
There are two groups of foreign bodies: those that are radio-opaque, (visible on X-ray) and those which are radiolucent (Box 6.3). Radio-opaque objects include metal, glass, grit and tooth. Wood, a common foreign body, is not radio-opaque, although it may be visible on X-ray film if it is covered with a metal-based paint.
Box 6.3
• Glass, metal, tooth and bone are radio-opaque – request SOFT TISSUE VIEWS from your radiographers.
• In the case of strong suspicion of a non-radio-opaque foreign body, ultrasound may be appropriate.
• Ensure that your own immunisations against tetanus and hepatitis B are up to date.
• Wear gloves when dealing with wounds.
• Observe hand washing and aseptic procedure routines.
• Dispose of any sharps promptly and personally.
• Clean up any blood spillage.
• Clear away your own equipment.
• Never resheath needles.
• Deal with any needlestick injury in line with your local policy.
Ultrasound may detect foreign bodies which cannot be seen on X-ray films. If there is a strong reason to suspect that a foreign body is present in a wound, refer the patient for investigation.
Damage to an underlying structure
It is important to exclude the possibility that any structure which lies below the skin, in the area which the wound might reach, has been damaged. Over the head, neck and trunk, this may include an injury to a vital organ. In the limbs, the tissues which will be affected are the nerves, blood vessels, bones, joint structures and muscles.
The commonest site of accidental wounding is the hand, and this question is nearly always relevant here. The hand combines power, finesse and mobility in a structure which is not bulky. One of the reasons for this is that much of its muscle power is generated from a distance and transmitted along a network of long, cable-like structures, the tendons, which travel almost to the tips of the fingers. These tendons, and the nerves and blood vessels which accompany them, lie just below the skin, on top of an unyielding surface of bone. They are vulnerable to division by cutting or crush. The hand also has a large number of joints in a relatively small area, and these can be injured by penetrating wounds.
Late presentation
If a wound which requires suture is more than 6 hours old and it has received no treatment, it is assumed that infection has started to develop. Primary closure (see below) may not be appropriate. In fact, it may be acceptable to close the wound if other factors are favourable (such as an absence of dirt and devitalised tissue in the wound), but you should only do this if you have the knowledge and experience to make that decision. Do not close a wound if you are doubtful.
Assessment and exploration of wounds
Some considerations have already been discussed, the mechanism of injury, the patient’s lifestyle, medical history and medications (with particular interest in antibiotic and Elastoplast® allergy, anticoagulant, immunosuppressive or corticosteroid medicines, and a history of diabetes). These will inform an assessment of the patient and the wound.
This section will focus on factors specific to the wound.
The Injured tissue
The assessment of a wound will cover not only the extent of the damage but also the viability and health of the injured tissue. Important factors will include the patient’s age, the site of the injury, the patient’s health, the quality of the circulation and nerve supply at the injured area, the frailty of the skin, whether or not the wound will affect a major function such as walking or eating, and the cosmetic significance of the wound. These considerations will influence the management of the injury.
Exploration
A fundamental concept is never close a wound unless you have seen its base.
The purpose of wound exploration is to discover the extent of the damage and the threat to the injured tissue. The main categories of problem that will be assessed are damage to underlying structures (see above); the presence of devitalised tissue, which will cause infection; the presence of dirt; and the presence of other foreign materials (commonly, wood, glass and metal).
These risks cannot be assessed if the wound cannot be seen clearly. There must be a good light source (preferably an adjustable spot lamp). Bleeding and pain must be under control.
The initial unpleasantness of bleeding and tearing of skin can make a superficial wound seem worse than it is. The lack of those signs can make a penetrating wound seem trivial. The tendency to underestimate innocuous looking wounds is not confined to patients, and you must guard against it. Be extremely curious about every aspect of a wound and answer all of your questions before it is closed. It might be expected that an open injury would be easier to assess than a closed one such as a sprain, simply because the access to the damaged tissue is greater. Often, this is not the case.
Penetrating wounds are, by definition, longer than they are wide, and for all that they are open, they are not accessible. Any worrying feature – dirt, foreign body, penetration to a vital area – will lie deep. Penetrating wounds can be assessed indirectly, by probe (do not probe wounds which are near vital organs), and by testing the function of the underlying structures. They can be cleaned by irrigation. They can be X-rayed for foreign bodies. However, except in the cases where surgical exploration is required, they resist a comprehensive inspection and full cleaning. They are prone to many complications and can threaten life and limb.
The difficulty of assessment is not, however, confined to penetrating wounds. Wounds are intrinsically deceptive. Once a wound has stopped bleeding, a clot forms, and the deeper layers of the wound can be covered and held together. Subcutaneous fat is a globular, clustered material and it can be hard to tell if it has been penetrated. Anyone who has experience of wound assessment will remember cleaning an apparently shallow wound which has suddenly popped open to reveal a much deeper injury. This becomes more likely when the wound is a few hours or days old.
Another factor which leads to concealment of the extent of an injury is that the different tissues under the skin have varying degrees of mobility. If a patient closes his fist and punches through a pane of glass, cutting his knuckles and partly dividing his extensor tendon, there is no point in lying the hand flat to explore the wound. The tendon moves over a greater distance than the skin when the hand is opened and closed, and the divided part will no longer be visible in the wound. Find out what position the hand was in when it was injured and explore the cut in that position. It is wise to inspect the wound through the whole range of movement.
A related problem is that tendons which are completely divided by an injury will shrink or be pulled away from the wound by the contraction of muscles and the movement of joints. There is no comfort in the fact that a tendon cannot be seen in a wound if there should be one there. You must know the relevant anatomy to assess the wound. Supplement a visual inspection by tests of the function of the local tendons, nerves and circulation.
Another difficult feature of wounds is that many of the common complications develop over a period of hours or days. The signs of infection do not usually appear in the first few hours. The loss of sensation which heralds a damaged sensory nerve may deepen over days. A partly divided tendon may fulfil its function, although its action will probably be weak. Later, it may divide completely. Complete division of the central tendon of the extensor mechanism of the finger, at the proximal interphalangeal joint (PIPJ) may be concealed by the fact that the lateral tendons will continue to work as extensors of the PIPJ, perhaps for days; however, the boutonnière deformity (see Chapter 4) will develop eventually. There will be little hope of a good recovery at that stage.
A sterile, round-tipped wound probe can be a helpful aid in wound exploration, for assessing depth in places that cannot be seen and for detecting, by touch, hard foreign bodies. Probes should be used very gently, and only in places where they will do no harm. A small curved mosquito forceps is a useful retractor.
When exploring a hand wound do not tie bleeding vessels: they are often very close to nerves. Do not excise any tissue, it is hard to replace and there is little to spare. Debridement may be necessary but it should be done by a specialist. Do not probe with anything sharp. The only sharp things you should use are needles for anaesthetic and suturing.
The term ‘exploration’ has been used here to describe a process which is performed in a minor injury clinic. A full exploration of a difficult wound is a surgical procedure, done in theatre conditions with good anaesthesia and instruments, and with the skills and resources to deal with any problems which arise. If your own skills and facilities are not adequate, do not be tempted to go too far. It is easy to stray out of your depth when dealing with wounds.
Other tests for complications
Consider the risks to any patient whose wound cannot be seen to its base. If the wound requires further exploration a surgeon may extend it in theatre. The indications for further exploration include, among others, a wound over a vital area, the known presence of a foreign body of fair size, a strong suspicion that a deep structure has been injured or the presence of dangerous contamination.
There are three main methods, in a minor injury clinic, to supplement exploration to exclude complications.
Observation
Observe for external signs of complication. The local signs of wound infection are pain, redness, heat, swelling, offensive discharge and odour, failure to heal and ascending lymphangitis (the ‘tracking’ red line moving proximally). The lymph nodes in the area may rise (often in the axilla or groin) and systemic signs, pyrexia and malaise, may develop.
Test of Function
Test the function of parts which may be injured. Always assess the nerves and circulation distal to the injury. Test that the patient can feel light touch, that pulses are present and that the colour and temperature of the tissues are normal. In a skin loss injury, assess sensation over the whole injured area to exclude a full thickness wound.
Test tendons carefully. There are two main concerns.
• A problem may be overlooked, for example if a particular function is carried out by more than one muscle and only one of them is damaged. Tendons which move distal joints will also contribute to the movement of every joint that they pass over. Tests can be used which isolate the single tendon that is giving concern.
• A tendon injury can be worsened, for example if there is a piece of glass in a wound and the tendon is mobilised over it, or if a tendon is partly divided and the test completes the job.
A tendon test should be applied against resistance to be conclusive, with power compared with the other side. A patient may retain active movement by using a substitute tendon, or a partly damaged one, but should not have full power. This test has the potential to worsen damage. Do not do it if there are already grounds to think the tendon is cut. Apply and release the resistance gently, and stop at once if there is weakness. Sometimes the pain of the wound prevents the patient from using full power.
Radiography
X-ray can be used to exclude bone injuries where an open fracture is possible and to reveal metal or glass foreign bodies.
Wound cleaning
Consensus is lacking on certain matters which surround the subject of wound cleaning. Some recommendations, such as those on the role of antiseptics in cleaning, are prone to pendulum swings, which makes confident practice difficult. Topics which are debated include the effectiveness of chemical cleansers in reducing infection and the toxicity of cleansing agents to healthy cells in the wound. In spite of this, the clinicians whose writings are current have a large core of agreement on the advice that they offer for day-to-day treatment of acute wounds.
There are given reasons for cleaning a wound, and a recent, untreated, traumatic wound should always be cleaned thoroughly. However, some wounds should be left undisturbed. If a wound is not new, and is dry, clean and healing, with no signs of infection, you should leave it. It is also wise to advise patients on such matters. There can be a tendency to overuse powerful disinfectants at home.
Reasons for wound cleaning
Infection
A thorough and effective wound toilet is the key measure which will reduce the risk of infection in the wound. This includes measures such as debriding necrotic or contaminated tissue, evacuating haematoma and getting rid of foreign matter, both small particles of dirt and larger objects. What constitutes an effective wound toilet depends on the nature of the wound and the infection risk factors which apply to the particular injury.
Cosmetic
The discussion on abrasions (above) has already covered the need to remove all dirt embedded in the dermal/epidermal tissue so that it will not form an unwanted tattoo. The cosmetic issue is also linked to the question of infection. An infected wound will not heal, sutured edges will break down, the wound may have to be reopened, and any scarring will be worse than it need have been (Box 6.5).
Box 6.5
• The scar develops over a year.
• Final appearance depends upon the patient, and upon events.
• Infection, diabetes, vitamin C deficiency, collagen disorders, renal failure, corticosteroids, chemotherapy, immunosuppressants contribute to poor scars.
• Poor outcome increases with extremity wounds, wide wounds, poorly apposed wounds, associated tissue trauma, use of electrocautery and infection.
• Scarring depends on static and dynamic tensions at the wound.
• Static tensions stretch the skin on bone when the patient is still.
• Dynamic tensions stretch the wound when muscle or joint movement occurs.
• Langer Lines are the directions of minimum static tension in the body. Wounds which follow these have better outcomes. Wounds which cross them perpendicularly have poorer outcomes.
• Scar width is related to the force required for closure. Methods to reduce wound tension include tissue undermining (dividing the dermis from the subcutaneous fat to reduce tension in the skin edges) and deep suture.
• Gaping of wound at rest and in motion gives an estimation of the potential outcome.
Exploration
A wound cannot be explored if it is covered in dirt, and the discovery of foreign matter of any kind in the wound, which may cause infection, inflammation or injury, is one of the objects of exploration. Cleaning and exploration are reciprocal activities which are discussed separately but carried out together.
Cleaning agents
Water
The effective removal of dirt, as opposed to bacteria, is more a matter of how much rather than what fluid, and the ordinary tap is the best source of an unlimited supply.
Saline
Normal saline is widely used for cleaning wounds, both for wiping the wound edges and for irrigation of the open area. It will not irritate the damaged tissue but neither does it have any antiseptic effect.
Povidone iodine
Povidone iodine is a combination of substances of which the active agent is iodine, an antiseptic which acts against Gram-positive and Gram-negative bacteria as well as fungi and viruses. The preparation of povidone iodine which is used as a surgical scrub contains a detergent which is not intended for use in open wounds. Trott (2005) recommends a 1% solution of povidone iodine in saline for wound periphery cleansing. It retains its antibacterial effects with no apparent toxicity problems.
Chlorhexidine
Chlorhexidine is an antibacterial agent which Trott (2005). describes as having strong Gram-positive action but, perhaps, a weaker Gram-negative action than that of povidone iodine. He cites a particular benefit in the use of chlorhexidine as a hand cleaner. It can build up on skin and apparently suppresses bacterial activity over a longer period than other cleansers. He also recommends it as a wound periphery cleanser. He advises against using the detergent-based hand-scrub in the wound itself.
Methods of wound cleaning
Lacerations and cuts
The need for adequate anaesthesia has already been discussed above.
Continue cleaning until there is no visible dirt in a wound and the tissue has a pink, fresh look, possibly with a little bleeding.
Cleaning is taken in two stages.
1. The edges of the wound, where tissue is intact, are wiped as vigorously as is required to clean away all visible dirt and blood. The technique is to wipe away from the edge, using a wet gauze swab, so that no contaminants or microbes are carried into the wound. A patient who is covered in oil or paint may need to use Swarfega to clean the skin, avoiding the open wound.
• Site of wound – the lower leg heals slowly, the face heals quickly.
• Blood supply – the face heals well because it is vascular.
• Wounds over joints tend to heal more slowly.
• Good closure technique and careful handling of tissue.
• Tidy wounds have better outcomes.
• Cause of wound – incised heals better than crush.
• Delay in treatment – infection.
• Patient’s health, nutrition and medications.
2. Irrigation is considered to be the best way to clean the open wound area because rubbing or scrubbing can damage wound cells, and materials like gauze or cotton wool can leave strands in the wound.
The best way to achieve a reduction in bacteria in a wound is to irrigate under high pressure, regardless of which cleaning material is used. Irrigation is also effective for removing a good deal of visible dirt. If there is serious contamination, other techniques may also be required. High-pressure irrigation is described slightly differently by different clinicians, but the commonest recommendation is to use a 20ml syringe with a 19 gauge needle and direct fluid from very close range, at full power, into the wound. This is said to create a pressure of 8psi. A large amount (up to 500ml) may be required. Splash guard precautions should be taken and there may be a fair amount of mess.
Penetrating injuries are, by their nature, impossible to clean in a satisfactory way, but high-pressure irrigation can be used on the punctures which commonly occur to the sole of the foot or the hand, which do not require surgical exploration.
Abrasions
The particular reasons for the need to clean abrasions thoroughly have already been discussed earlier in this chapter.
A fresh abrasion is very painful. Cleaning may have to be vigorous, often with a brush, and some pieces of dirt may need to be picked out from little sacs of skin with needle or forceps. Dirt may be ingrained like a permanent stain and may not surrender even to scrubbing with a brush. Children are often injured in this manner and the management of a child’s distress may be difficult.
There are topical anaesthetics available for use with children for both grazes and suture. They must be properly applied to soak into the affected site and they must be left for the time required for them to take effect. Such agents sting on application but this settles quickly and they make cleaning possible without resorting to a general anaesthetic at least in some cases. It is also possible to infiltrate small grazes with an injection of lidocaine. The usefulness of injected local anaesthetic for cleaning abrasions is restricted because larger grazes require amounts which exceed the maximum dose. Extreme care has to be taken in this regard with children. Abrasions which are large, or which are on the face, may require cleaning under a general anaesthetic.
If you are considering treating a child, think carefully about the possible problems, and refer if there is any doubt.
Debridement
Wound cleaning is part of a continuum which includes techniques to remove contaminants and devitalised tissue. If these procedures are indicated, the patient may require surgical referral, not only because of the difficulties and risks which wound cleaning presents but also because that degree of contamination raises other issues, such as wound closure and antibiotic prophylaxis.
Wound infection
Infection is the main complication of traumatic wounds. The steps that are taken to prevent infection when a new wound is treated may be an important contribution to healing. You will also see and treat established infections which are still local to the area of the wound. If the infection is moving beyond the wound or the patient is ill, he may need admission to hospital for intravenous antibiotics and surgical management may also be considered.
What is a wound infection?
The skin, along with other areas of the body, is colonised by commensal flora. These are microorganisms which coexist with each other and their host and cause no illness as long as they are checked by their neighbours and stay in their given area. A wound, a break in the skin, allows these microbes to penetrate where they should not be. It also involves the violent invasion, through the barrier of the skin, of some implement from the dirty outer world, shedding its own load of microscopic life forms. The patient then visits a hospital and is exposed to the infection hazards which medical treatment entails.
An organism which multiplies to an extent where it causes harm to its host is called a pathogen. The harmful process is an infection. The collective term for the organisms which cause most of the wound infections which concern a minor injury clinic is bacteria.
Bacteria are subdivided into groups by their shape, their response to laboratory staining and their need of oxygen. Three bacteria are mentioned here. A fourth, which causes tetanus, will be discussed in greater detail below.
Staphylococcus aureus is an aerobic Gram-positive bacterium and it appears, from the frequency with which it is cultured from swabs, to cause most of the traumatic wound infections which are seen in hospital. It is highly resistant to penicillin but sensitive to flucloxacillin and erythromycin. It is a commensal, found in the nares and other sites where there is hair or mucous membranes. It can cause superficial wound infections and abscesses, osteomyelitis and septicaemia. The toxin-producing variety can cause the fatal toxic shock syndrome, which is best known in relation to tampon use.
Streptococcus pyogenes is also a Gram-positive aerobic bacterium, and another common offender in traumatic wound infections. It is sensitive to penicillin and erythromycin. It is a commensal in some people and is found in the mucous membranes. It also causes cellulitis and can cause necrotising fasciitis, septicaemia and toxic shock.
Clostridium welchii is an anaerobic Gram-positive bacterium. It, and other organisms of the same family, cause gas gangrene infection, a dire threat to life and limb. It is a commensal of the human gut and is found in soil. It can form spores and lie dormant in a protective shell, highly resistant to destruction, until conditions are suitable for it to multiply. Anaerobes flourish where oxygen is lacking. Wounds with devitalised tissue are ideal ground for reproduction. The reproducing organism creates gas, hydrogen and nitrogen, and exotoxins’ which consume healthy tissue and threaten systemic collapse. Clostridium welchii is sensitive to penicillin.
The wounds which are prone to anaerobic infection are those with violent tissue destruction under dirty conditions, such as war injuries and farmyard accidents. As a general rule, these are severe injuries and will not be seen in a minor injury clinic. Among wounds which are likely to be seen in minor injury clinics, dirty penetrating wounds which are difficult to clean at the base are at the greatest risk of anaerobic infection.
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