The ankle Lateral ligament inversion sprains are the most common soft tissue injury to the ankle and present with: - Swelling - Tenderness - Difficulty bearing weight. Differentiatio n from a fracture can be difficult. Complete absence of tenderness over both malleoli and t he fifth metatarsal makes a fracture very unlikely. Bony tenderness mandates referral to ho spital for an X-ray. Minor sprains can be treated by RICE. Achilles tendon ruptures Achilles tendon ruptures most commonly occur due to asymptomatic d egeneration in the tendon or as an acute event, often on the sports field or squash court. There may be an audible snap or the patient may feel as if they have been kicked or hit in the back of the leg, although no contact has occurred. Clinically, there is pain and tenderness in relation to the rupture with a palpable gap if examined early. Most commonly, there is an inability to bear weight and a major compromise of plantar flexion. Absence of plantar flexion, when the patient \200\231s calf is squeezed with the patient in the kneeling position, is diagnostic of Achilles tendon rupture. (Simmonds test). Pre-hospital treatment is symptomatic only. The patient should be taken to the emergency department for definitive management. This page intentionally left blank CHAPTER 3 Trauma 280 Spinal injuries Spinal injuries range from simple soft tissue sprains to fractures, stable or unstable, with the potential for spinal cord injury or the presence of established spina l cord injury. In general terms, all patients with an appropriate mechanism of injury shoul d be regarded as having a spinal injury until proven otherwise and should, therefore, be su bjected to spinal immobilization. Spinal injuries commonly follow: - Road traffic collision s - Falls - Gymnastics\trampolining - Rugby/football - Horseriding Road traffic collisions are the most common cause of injury and are responsible for 50% of patients suffering spina l cord injuries. Compres- sion/flexion and extension/rotation are the common forces involve d. Lesser injuries include whiplash injury due to rear end shunts producing flexion followe d by extension. Skiing - Hang-gliding - Aquatic activities - Weights falling onto the back. Whilst the majority of injuries are in the cervical spine, 10% of these patients have a second spinal injury. Falls, in particular, are associated with thoracolumbar fractures. Scrummage injuries in ru gby are commonly associated with cervical spine injury. Aquatic sports, particularly diving into a shallow pool, often produce a combination of head and cervical spine trauma. Histor ically, falls onto the back in coal miners produced major thoracic and thoracolumbar fractu res. Certain criteria must be fulfilled if the spine is to be cleared of any injury at scene (See box opposite). Assessment If there is a high index of suspicion of spinal injury based on the mecha- nism of injury, the spinal column should be protected, unless the patient \200\231s spine can be cleared following the criteria detailed in the box opposite. The patient should not be all owed to get up and, ideally, should be main- tained in the supine neutral position. In the case of road traffic collisions, the neck should be moved to a neutral position and inline spinal stabiliza- tion maintained prior to and during extrication. An inability to achieve a neutral position suggests the possibity of a fracture dislocation, in which case the neck should be maintained in as near neutral position as possible. No attempt should be made to forcibly restrain or fasten down an aggressive, unco-operative patient. Such patients may sometimes tolerate a cervical collar alone, which must be accep ted as \200\230better than nothing \200\231. Such aggression may be the result of hypoxia and, if present, this should be identified and treated. SPINAL INJURIES1 281 Criteria for cleaning spine of injury - There is no altered level of consciousness - The pa tient is not under the influence of alcohol or drugs - There is no midline spinal tendernes s - There are no neurological signs or symptoms - There are no other distracting painful in juries - There is no history of previous spinal injury - The patient does not suffer from a n inflammatory arthropathy such as rheumatoid arthritis or ankylosing spondylitis Segment Representative dematomes Representative myotomes Sensation over detoid Sensation over thumb Sensation over middle finger Sensation over litt le finger Sensation over inner aspect of elbow Sensation around nipple Sensation over xiphi sternum Sensation around umbilicus Sensation around symphysis Sensation in inguinal region Sensation anterior upper thigh Sensation anterior mid thigh Sensation on medial aspect leg Sensation between 1st and 2nd toes Sensation on lateral border of foot Sensation over ischi al tuberosity Sensation around perineum C5 C6 C7 C8 T1 T4 T8 T10 T12 L1 L2 L3 L4 L5 S1 S3 S4/5 Deltoid muscle Wrist extensors Elbow extensors Middle finger flexors Little finger abductio n \200\223 \200\223 \200\223 \200\223 \200\223 Hip flexors Knee exensors Ankle dorsifl exors Long toe extensors Ankle plantar flexors \200\223 \200\223 Fig. 3.19 Motor and sensory levels. Reprinted with permission from Greaves I et al., (2001) . Trauma Care Manual. Hodder Arnold. CHAPTER 3 Trauma 282 The conscious patient may complain of motor weakness or altered sensation, the extent of wh ich will depend on the level of injury. Important anatomical landmarks and their relevance are summarized below (and in Fig. 3.19): - Injuries from C1 \200\2232 \200\224the patient i s unable to breathe because of intercostal and diaphragmatic paralysis and will die unless they receive basic life support Injuries at C3 \200\223C5 \200\224depending on the extent of the injury, the diaphragm may be functional or non-functional due to paralysis of the phrenic nerves. Over a period of time, patients who may initially be able to cope are at risk of developing resp iratory failure due to exhaustion or progression of diaphragmatic deficiency due to spinal cord swelling. Injuries between C5 and C7 \200\224there is complete loss of intercostal function. However, the phrenic nerve and the diaphragm are functional. The patient displays a seesaw pattern of breathing. - Injuries between T1 and L2 \200\224there will be a variab le loss of intercostal muscle function and, therefore, respiratory compromise depending on the level o f cord injury. The higher the level of injury, the greater the deficit. Above the level of T6, there is sufficient loss of sympathetic outflow to produce neurogenic shock. This is ch aracterized by bradycardia, a low blood pressure (usually 70 \200\22380mmHg), and distal pe ripheral vasodilatation. Male patients have priaprism (sustained penile erection). The flaccid paralysis and areflexia associated with a spinal cord injury is commonly referr ed to as spinal shock. This is not \200\230shock \200\231 in the normal pathophysiological sense but a state of electrical interruption to the cord: spinal concussion. This should n ot be confused with neurogenic shock and the term spinal shock is best avoided. In the unconscious patient, there will be no specific complaint of pain and no verbal commu nication regarding motor or sensory deficit. The physical signs detailed above may suggest spinal cord injury. A high index of suspicion and mandatory full spinal immobilization are necessary. Management Primary survey Problems due to spinal injury may be detected during the primary survey. Examples include: - Inadequate breathing and ventilation due to intercostal or phre nic nerve compromise. Hypotension, bradycardia, distal vasodilatation, and priaprism due to neurogenic shock. Motor and sensory deficit due to neurological injury. Secondary survey A detailed secondary survey which involves a head-to-toe examination is no rmally carried out in the emergency department. During the log roll, local tenderness, defo rmity, and palpable steps in the spinal column may be detected. A rectal examination may re veal a lax anal sphincter. SPINAL INJURIES1 283 Patient positioning Airway always take precedence over the cervical spine. Where possible, the cervical spine should be maintained with inline spinal immobilization. The supine neutr al body position is ideal. In road traffic collisions, the cervical spine should be maintai ned in a neutral position pending full. Immobilization Patients should be extricated from vehicles maintaining a stable straight sp ine, onto a spinal board, followed by the application of securing body straps, head huggers , and their supporting straps. It is common practice in the UK for these patients to be tra nsported to hospital whilst on a spinal board. Where there is an extended traveling time, c onsideration should be given to transferring the patient onto a vacuum mattress using a sco op stretcher. In the unconscious patient, once secured to the spinal board, the cervical collar should be released to avoid compression on the external jugular vein which can lead to raised intrac ranial pressure. Transportation Consideration should be given to the use of helicopter transportation for ex pediency, reduced transportation time, and transportation to the most appropriate hospital. CHAPTER 3 Trauma 284 Amputation Traumatic Traumatic amputation is fortunately rare. Re-implantation of the amput ated part(s) may be possible in guillotine type injuries, but is rarely an option in crush or avulsive amputations. Nevertheless, the amputated part should always accompany the patie nt to hospital since it may be used as a source of tissue for reconstruction. Surgical Surgical amputation is rarely necessary pre-hospital. It should not be undertaken without the necessary training and equipment. Amputated parts When their size permits, amputated parts should be wrapped in sterile dress ings dampened with saline and placed in a waterproof bag or con- tainer. This should then b e surrounded by a bag or container holding a mixture of ice and water. The amputated part m ust not be allowed to come into direct contact with ice for any length of time. This page intentionally left blank CHAPTER 3 Trauma 286 Blast and gunshot injuries Introduction Trauma caused by bomb blast and guns is increasing. Gun-related violence is now commonplace on the streets of our big cities. A responsible at titude from rescuers and scene safety are critically important. Therefore: - Do not approac h the scene until it is declared safe from the risk of further shooting, secondary devices, fire, and building collapse. The police may determine a rendezvous point at a safe distanc e from the incident until the scene is declared safe. - Do not touch objects or disturb the environment except to treat patients, as the incident is a forensic scene. Do not disturb dead bodies unless to give access to casualties or if they are at risk of further damage or destruction. When the scene is declared safe, it may be necessary, in the case of multiple casualties, t o initiate a triage sieve. If a major incident has been declared, the rescuer should work u nder the directions of the appropriate incident officer. Patient assessment should follow the normal ABCDE system regardless of the nature of the injuries. Blast injuries Blast injuries may occur in the following situations: - Terrorism - Domestic incidents (for example, gas explosions) - Industrial incidents (for example, chemical expl osions). Blast injury mechanisms Blast (shock) wave Following detonation, the explosive substance is instantaneously con- verted into a large volume of gas, producing an expanding shock or bl ast wave. The shock wave is similar to a sound wave (but much faster) and produces an almos t instantaneous rise in pressure. The shock front spreads out from the point of detonation as a hemisphere but the pressure declines dramatically as the distance from the detonation increases. The effect of the blast wave is accentuated, however, in closed environments whe re reflection from surfaces occurs and summation of incident and reflected waves results in increased pressures. BLAST AND GUNSHOT INJURIES1 287 Peak overpressure e r u s s e r P Positive phase overpressure duration Atmospheric pressure Time Fig. 3.20 Idealized blast overpressure waveform. Blast wind Behind the blast, shock wave is an area of turbulence \200\224the dynamic overpr essure or \200\230blast wind \200\231. This consists of a rapidly expanding turbulent fire ball of hot air and products of combustion. Fragmentation Most military explosives are cont ained in shells or cases which will fragment on detonation (grenades, mortars, and artiller y shells). These weapons are designed to fragment in a way which causes the maximum possibl e injuring potential. These are primary fragments. Terrorist devices may use nails or ball bearings as primary fragments. Fragments of the envi- ronment such as shattered car body wo rk, masonry, furniture, or the body parts of victims will all act as secondary fragments if sufficiently energized by the blast wind. Thermal injury The immense thermal output from a n explosive detonation is usually asso- ciated with flash burns which, although painful, ar e usually of relatively minor clinical significance. Ordinary clothing usually offers a rea sonable degree of protection. However, deeper, more serious burns, may occur if the environ ment ignites as a result of the detonation or there is an incendiary component to the explo sive device. Industrial or chemical explosions are significantly more likely to be associat ed with serious burns and terrorists may use accelerants such as gasoline in simple improvi zed devices. Patterns of injury Blast injuries are classified as follows: - Primary injurie s \200\224result from the blast (shock) wave - Secondary injuries \200\224from fragments - Tertiary injuries \200\224due to the blast winds - Burns \210\227 - Crush injury \210\227 - Psychological effects \210\227 \210\227 Sometimes referred to as quaternary blast injurie s CHAPTER 3 Trauma 288 Primary blast injuries Primary injuries result from exposure of the body to the blast shock wave. The structures most at risk are those at solidfluid interfaces and those containing a ir such as the bowel, lung, and ear. The most important primary effect is to the lung, producing lung contusion and hemorrhage into the alveoli. Features of blast lung include: Breathlessness - Dry cough - Chest pain - Restlessness - Confusion and agitation - Pneumoth orax and haemothorax. The incidence of blast lung is low because those near enough the deto na- tion to suffer significant primary blast injury site usually die as a result of fragmen tation or tertiary injury. The ears are very sensitive to primary blast injury and rupture of the tympanic membrane is common. Deafness is a sign of significant blast injury. However, it only occurs if there i s direct orientation of the auditory canal to the blast wave. Thus, although deafness is an indicator of significant blast exposure, its absence does not imply that the patient has e scaped significant injury elsewhere. The patient may not be ignoring you \200\224they may be deaf! Injuries to gas-containing abdominal organs include immediate perfora- tion, intestinal wal l hemorrhage with delayed perforation, mesenteric tears, and retroperitineal haematomas. Al though rare in explosions taking place in air, they are more commonly seen following underw ater explosions. The treatment for all scenarios follows the ABCDE system. Secondary injuries The majority of patients close to the explosion will have multiple injur ies caused by fragments from the explosive device (bomb casing or nails) or blast wind ener gized debris (masonry, glass, and wood). Injuries may be blunt or penetrating, the latter i nvariably have significant contamination. Tertiary injuries Tertiary injuries are produced by the blast wind. Displacement of indi- v iduals may result in whole body disruption or disintegration, traumatic avulsion amputation s, and crush injury. Other injuries may be caused by bodily impact. The amputations occur t hrough long bones fractured by the blast wave and are avulsive, with considerable proximal damage. Burns Flash and flame burns occur in explosions. Flash burns are usually super- ficial and are related to the heat generated at the time of detonation. Flame burns may occur due to s econdary ignition of the environment. BLAST AND GUNSHOT INJURIES1 289 Crush injuries Entrapment following collapse of buildings due to blast is common. Patients often sustain multiple injuries. Delay in rescue may result in a risk of crush injury progr essing to crush syndrome. At scene, appropriate fluid replacement and high-flow oxygen may influence outcome. There is no role for tourniquets in crush syndrome (except for control o f life- threatening bleeding from associated injuries). Vigorous fluid resuscitation and im mediate evacuation is essential. Psychological effects Significant numbers of patients and emergency workers will suffer ong oing psychological problems following an explosion. This is undoubtedly related to the muti lating nature of the injuries and the likelihood of survivors being personally acquainted w ith each other and the dead. For the majority, the outlook is good. Critical incident debriefing may be helpful and is c ommon practice amongst emergency service person- nel. All patients and personnel involved s hould have some arrangement for follow-up which may be in-house for the emergency services or through general practitioners for patients. Similar arrangements should be available to support hospital personnel. Management The essential features of management are: - Triage: effective rigorous triage is essential. A triage sieve, followed by a triage sort, will identify the seriously injured amongst those with lesser injuries and will allow appropriate use of transportation and hos pital resources, particularly for those requiring continued resuscitation and surgery. The circumstances and mechanism of injury must be considered in determining transfer to hos pital (for example, a non-survivable head injury). A high index of suspicion should be maintained for inhalation injury and impending acute lung injury, especially from explosions in confined places. High-flow oxygen with a non re-breather reservoir bag is mandatory if lung injury is suspected. Careful assessment for signs of abdominal injury \200\224often there are very few clinical signs early on, particularly in the presence of a hollow viscous injury. Deafness is the hallmark of potentially significant blast injury. All such patients should be carefully assessed and transported to hospital. Absence of deafness DOES NOT imply absence of a significant blast load. Primary and secondary fragment injuries are very common and are almost invariably multiple. External hemorrhage should be controlled by direct pressure and wound dressings. It is not necessary to dress every wound. Adequate analgesia is essential for its pain-relieving and anxiolytic features. Avulsed limbs should be sent with patient to hospital. Re-implantation will not be possible , but they may provide tissue for reconstruction. CHAPTER 3 Trauma 290 Gunshot injury Wound ballistics and mechanism of injury Wound ballistics is the study of in jury caused by ballistic weapons. The degree of tissue damage caused is related to the acut e energy transfer where: KE = mv2 KE = kinetic energy; m = mass; v = velocity If a bullet is stopped by tissue, all the energy is used ( \200\230transferred \200\231) ca using damage to that tissue. If, however, the bullet passes through a tissue without slowin g, depending on the site of impact, very little dam- age may occur. For example, a bullet s triking the femur may be arrested in motion, shatter the femur, and produce extensive soft tissue damage whereas a bullet going front to back through the lung, without making bony co ntact, may cause relatively little damage. The amount of energy transferred will also be af fected by the stability and shape of the missile. Missile penetration into the body results in crushing or laceration. The results will depen d on the anatomical site and the structures involved. Damage to apparently remote structure s may result from missile deflection off bone or damage from secondary bony fragments. Wounding missiles The old concept of high-and low-velocity missiles has been replaced by th e concept of energy transfer, since it is this which determines the damage produced. Wounds can therefore be described as: - High-energy-transfer wounds - Low-energy-transfer wounds. The same amount of damage can have different effects depending on the anatomical site. For example, a wound to the forearm is unlikely to be fatal whereas a similar wound to the hea rt almost certainly will be. The external appearance of both entry and exit wound may have little relation to the intern al damage, especially if a major deflection or frag- mentation of the missile has taken pla ce. Similarly, although the exit wound is usually bigger than the entry wound, this is not invariably the case and, indeed, is clinically of no relevance in the initial management. T he rescuer, therefore, should concentrate on the ABCDE assessment rather than being concern ed about ballistics. The interface of bullets with tissues Injury severity is governed by: - Temporary cavitatio n - Bullet fragmentation - Wound contamination. BLAST AND GUNSHOT INJURIES1 291 Temporary cavitation In low-energy wounds, tissue damage is largely confined to the tract o f the missile. In high-energy transfer wounds, however, injury extends radially from the wo und as a result of the formation of a temporary cavity, due to the transfer of large amount s of energy causing the tissues to accelerate away from the path of the missile. This tempo rary cavity results in negative pressure which sucks in dirt and debris producing gross con tamination. The temporary cavity then collapses. The amount of energy transfer is determined by the shape of the mis- sile and the features of the tissue. Elastic tissues such as lung may stretch and remain largely intact. Solid or gans such as the liver, loaded colon, or bone may suffer catastrophic injury. The maximal c avity size is often deeply placed within the wound tract, (for example, within the chest or abdomen). In the limbs, where impact on bone is a feature, the cavitation may produce an e xtensive large ragged wound. Fragmentation Energy transfer is increased if the area of the bullet striking the tissue is increased. Conventional military weapons have an outer casing or metal jacket to prevent f ragmentation or deformity. However, stability may be lost on contact with human tissue. The bullet may yaw (angle from side to side) or tumble (turn over). Maximal energy transfer oc curs if the long axis of the bullet is at 90 degrees to its axis of penetration, and a more extensive complex wound results. If a bullet breaks up or deforms within body tissues, the effect may be devastating. Conven tional bullets which are fully jacketed should not fragment. Bullets may be designed to fra gment and deform, resulting in a maximum \200\230energy dump \200\231 and tissue destructi on. Cavities may be large and, if affecting vital areas, often result in fatal injuries. Bu llets used by the law enforcement agencies are designed to deform for maximum \200\230stop - ping \200\231 potential with minimal risk of collateral injury due to the bullet passing straight through the intended victim. Bullets can be easily altered to deform or fragment. Wound contamination All bullet wounds should be assumed to be contaminated. High-energy tra nsfer wounds produce cavitation with negative pressure leading to indrawing of clothes and debris (including fecal material) into the wound. Missile tracks The track of a bullet cannot be predicted from the entry wound. In addition to the factors discussed above, the position of the patient at the time of wounding (which may not be known to the clinician) will materially effect the wound track. CHAPTER 3 Trauma 292 7.62 mm NATO Vel: 2830 f/s (862 m/s) wt: 150 gr (9.7 gm) FMC Permanent cavity Temporary cavity 0 cm 5 10 15 20 25 30 35 40 45 50 55 60 64 Fig. 3.21 Ballistic injury: temporary and permanent cavities. Reproduced from Emergency War Surgery \200\2242nd United States revision. NATO handbook 1988. Permission requested from US Government printing office, Washington DC. BLAST AND GUNSHOT INJURIES1 293 Types of missile Bullets Handguns generally fire jacketed lead bullets producing low-energy transfer wounds and injury along the track of the projectile. The clinical significance wi ll depend on the tissues involved. Police and hunting weapons are designed to produce a contained injury with a \200\230clean drop \200\231 and minimal risk of collateral damage. These partially jacketed bullets defo rm on impact and produce high-energy wounds. Modern bullets (military and terrorist) have full metal jackets and are not intended to def orm. They may fragment causing devastating energy transfer wounds. Baton rounds These are often incorrectly called rubber or plastic bullets. They are signifi cantly larger than conventional ammunition and are designed to stop by inflicting severe pa in from soft tissue injury. Skin penetration is very rare. UK guidelines restrict their use to impact below the victim \200\231s waist, making significant injury extremely unlikely. Fatalities in the past have usually been associated with impacts to the head or impacts in children. Basic attention to ABC, analgesia, and transfer to hospital for assessment and ob servation is likely to be all that is required. Airguns These produce single, low-energy wounds which are not normally significant, althoug h intracranial penetration has been recorded in children and there is also a risk of signif icant injury to the eyes. Shotguns These fire multiple pellets with a range of sizes from bird shot (smallest) to buc k shot. Fired at close range, they can act as a single missile causing massive tissue damag e. Management The provision of medical care at the scene of a shooting may present certain cle ar risks. If the police are present, their advice MUST be followed at all times. There must be NO risk of further injury before assistance (life-saving or otherwise) is offered. General principles - Make sure that it is safe to approach. - Follow an ABCDE protocol. - C onsider permissive hypotension in patients with penetrating chest or abdominal injuries. DO NOT become distracted by ballistics. - Treat what you find, not what you expect. - Remem ber that bullets behave erratically and may have penetrated several body cavities. Do not delay life-saving surgery by protracted on-scene times. - Do not come to any decisio n on wound severity. In general, bullet entry and exit wounds give little information about the patient \200\231s condition. CHAPTER 3 Trauma 294 Assume serious injury in all cases and arrange rapid transfer to hospital. Give adequate analgesia; provide reassurance. Management of wounds Chest wounds should be treated conventionally using an Asherman seal . Wounds elsewhere should simply be covered with a sterile dressing (moist if there is evis cerated bowel). Iodine should NOT be applied. Bleeding should be controlled by pressure: ca vities may require packing or pressure from fingers or a fist. If necessary, a tournequet s hould be used. Topical haemostatic agents such as Quickclot or Hemcon may be used for t he emergency control of life-threatening limb bleeding. The manufacturers instructions shou ld be carefully followed. Forensic considerations - Never remove clothes by cutting through wound holes - Ensure that clothes remain with individual patients and are handed to a named person (preferably a police officer) Do not speculate about ballistics - Do not touch any weapons - Do not speculate about crimi nal responsibility This page intentionally left blank CHAPTER 3 Trauma 296 Burn injury Pathophysiology A burn wound has three zones: - Zone of coagulation \200\224a c entral zone of destroyed cells producing an avascular wound area. Zone of stasis \200\224an area of injured cells which may die due to associated vasoconstriction and microthrombi. Zone of hyperaemia \200\224an area of minimal thermal damage with marked vasodilatation and an acute inflammatory response. Fluid loss Fluid loss from the burn surface occurs which is: - Due to vasodilatation and ch anges in blood vessel walls - Proportional to the extent of the burn - Present for 36 hours after injury In addition, all patients suffer a systemic inflammatory response and capilla ry leak which is related to the extent of the burn and contributes to fluid loss. In combin ation with cutaneous loss from the burn, this may produce hypovolaemia. Burn shock is slowe r in onset (greater than 1hr) than hypovolaemic shock which may be associated with other co existing injuries (for example, a house fire and injuries sustained jumping from the buildi ng). Infection Super-added infection is a critical feature in burns prognosis since many burns v ictims ultimately die of infection. Early attention to minimizing risk is, therefore, essen tial. Bacterial contamination can be reduced by wearing gloves when treating or moving a bu rns patient. Pain Pain from burn injury is produced by the exposure of nerve endings in burnt skin and f rom inflammatory mediators. Simple covering with cool dressings will have a dramatic effect in improving patient comfort but adequate analgesia is also vital. Hypothermia Burns patients, especially children, are at risk of hypothermia due to over zea lous cooling. Cool the burn and warm the patient is sound clinical practice. Death Early burn-related deaths are associated with airway obstruction and severe inhalatio n injury. Later deaths are often precipitated by sepsis with a sustained systemic inflammat ory response, acute lung injury, renal impairment, and myocardial depression, leading to mu ltiple organ failure. BURN INJURY1 297 Types of thermal injury Scalds - 40 \200\22350% of burns unit admissions are children, 85% of which are scalds in children under 3 years of age. Are commonly due to hot water or hot fluids from cooking, including kettles, saucepans, chip pans, cups and mugs. Are more common in the elderly due to an increased frequency of spilling hot liquids and slowness to react (for example, in getting out of a bath which is too hot). May be associated with a medical crisis such as hypoglycaemia or CVA. Are commonly associated with drugs and alcohol use. Flame burns - Are commonly associated w ith house fires, especially when clothes catch alight. Are often associated with children playing with matches or cigarette lighters. May result from smoking in bed (especially in the elderly). - Occur as a result of gasoline or accelerants associated with barbecue or bonfire accidents. May be associated with airway burns. - Are commonly associated with drugs and alcohol use. Explosive burns Burns resulting directly from the detonation of explosives are usually \200\230flash burns \200\231 against which normal clothing offers good protection. In some cases, however, the environment catches fire, in which case conventional flame burns will p redominate. Explosions involving flammable materials such as gasoline or gas will be associ ated with extensive burning. These may be domestic or industrial incidents or associated wi th incendiary terrorist devices. Contact burns Contact burns result from skin contact with a hot object and depend on the nature and temperature of the heat source and the duration o f contact. Chemical burns Chemical burns commonly follow domestic and industrial accidents but occasionally occur as a form of self harm. Most chemical burns require copious irrigati on. Four types of chemical burns require special attention: Cement burns Cement is a weak a lkali and causes burns on prolonged contact. It is a common source of lower leg burns in bu ilders. Phosphorus burns Phosphorus ignites spontaneously even in the presence of water. Ph os- phorus particles should be removed using forceps. This is made easier by applying 1% co pper sulfate solution which turns the particles black. Copper sulfate is in itself toxic an d should not be left in prolonged contact with the skin. Copper sulfate may be available in areas where phosphate is used. CHAPTER 3 Trauma 298 Phenol burns Phenol is absorbed through the skin and can cause renal failure. Water or sali ne soaks are contraindicated. Irrigation with copious running water is of benefit. Hydrofluoric acid burns Hydrofluoric acid causes intensely painful, deep burns. Treatment i s with copious irrigation with cold water followed by urgent transfer to hospital for calci um gluconate therapy. All rescue personnel must be protected from contact with the acid. Electrical injury Electrical injury may follow low or high tension current sources. Low ten sion characteristically produces small deep burns at entry and exit points with variable ti ssue damage between them. Depending on the anatomical path of conduction, there may be asso ciated cardiac dys- rhythmias. High tension burns from overhead cables may be associated wi th injuries due to a fall from a height. Ionizing radiation burns Burns from ionizing radiation are rare. They should be suspected i n any patient rescued from a fire at a nuclear installation. Treatment is with copious wate r irrigation using soap or detergent. It is essential that all rescue personnel avoid the possibility of contami- nation with radioactive materials. Flash burns Flash burns are caused by intense, very short exposure to severe heat, often pr oducing superficial or partial thickness burns. They may result from flame, radiation, or e xplosive burn injury. Normal clothing offers good protection against flash burns which are usually confined to exposed areas. Non-accidental injury (NAI) Non-accidental injury is most often seen in children, but may a lso occur in the elderly. Characteristic injuries include cigarette burns, scalds to the fe et and buttocks (from lowering into hot water), and burns with irons and other electrical a ppliances. Burn depth The anatomical depth of a burn can be divided into: - Simple erythema \200\224su perficial burn with no skin loss. Skin is red and tender and heals within 5 \200\22310 days with no scarring (typical of sunburn). Erythema is NOT included when counting burn area Superficial partial-thickness burns \200\224painful, with superficial blistering healing in 10 \200\22314 days. BURN INJURY1 299 Deep partial-thickness burns \200\224thick-walled blisters with a granular white skin and p inpoint red mottled areas. Associated pain may be limited because of damage to the skin adn exae. Deep full-thickness burns \200\224producing white leathery charred skin with no sensation. These burns commonly follow prolonged contact with a burning agent or dr y heat. Scarring is inevitable. Superficial partual-thickness burn Epidermis Germinal layer Deep partial-thockness burn Dermis Deep burn Subcutaneous fat Fig. 3.22 Anatomical diagram showing burn depths. Reprinted with permission from Greaves I et al. (2005). Emergency care: a textbook for paramedics, 2nd edn. W.B. Saunders Co. Ltd. CHAPTER 3 Trauma 300 Factors affecting the outcome of burns Extent of burns Surface area may be assessed using t he \200\230rule of nines \200\231 in adults or the \200\230rule of fives \200\231 in chil dren, for which standard assessment charts are available. The palm of the hand in adults (w ith the adducted fingers included) equates to approximately 1% body surface area. Assessmen t of the burns surface area is difficult in the pre-hospital environment and does not mater ially change management unless there is a significant transfer time to hospital. A simpler criteria is the \200\230rule of halves \200\231 using the following system: - Is over half of the patient burnt? - Is the area burnt between a fourth and a half of the patient \200 \231s skin surface area? Is the area between an eighth and a fourth of the patient \200\231s skin surface area? Is the area less than an eighth of the total skin surface area? A more detailed and accurat e assessment can be carried out after arrival in hospital. Burn site A poorer prognosis is associated with burns to the: - Face (often associated with smoke inhalation) - Hands or feet - Eyes - Ears - Perineum Burns involving these areas, ho wever small the surface area, require management in a specialist unit. Circumferential burns to the neck may produce airway compromise, to the chest, respiratory compromise, and to the limbs may be associated with limb ischaemia. There is no role for es charotomy in normal UK pre- hospital care practice although unusual circumstances may dicta te the need for local protocols. BURN INJURY1 301 15% 20% Front 20% 10% Back 20% Front 20% 10% 10% 10% Back 20% 10% 10% 15% 15% Child Infant Fig. 3.23 \200\230Rule of fives \200\231 (children and infants). The quoted percentages re fer to the front or back of the limbs, but to the whole of the head. Reprinted with permiss ion from Greaves et al. (2005). Emergency care: a textbook for paramedics, 2nd edn. W.B. Sa unders Co. Ltd. CHAPTER 3 Trauma 302 Inhalation injuries Inhalation injuries are a major cause of death due to: - Direct thermal injury by inhalation - Inhaled toxic substances - Systemic poisoning (for example, carbon monoxide) Age of the patient Mortality is increased in children under five years of age because child surface area is greater in relation to their total body size. The elderly are at risk because of poor healing potential and reduced physiological reserve. Associated injuries Causes of associated injury include: - Falls or jumps from a height in building fires - Impact injuries in road traffic accidents - Electrical injuries including arrythmias in electrocution Associated medical conditions Significant co-morbidities include ischaemic heart disease, d iabetes mellitis, steroid therapy, and immunocompromised patients. Immediate care of thermal injuries Scene safety - Ensure scene safety regarding avoidable r isks to carers. - Remove the patient from the heat source and extinguish flames, if necessary. Remove burnt and hot clothing. - Cool the burn area for up to 20 minutes. This should begin whilst waiting for evacuation and be continued during packaging and transfer. Primary survey - Determine mechanism of injury. - A Assess and open the airway, if necessar y. - B Assess breathing and ventilation and seek the signs and symptoms of smoke inhalation. Only in extreme circumstances should intubation be attempted in the field, in which case a smaller than normal endotracheal tube should be used. Wheezing should be managed by the adm inistration of nebulized salbutamol. If the airway is critically threatened, the two options are surgical airway formation or an esthesia and intubation. The former is safer in inexperienced hands (see page 178). BURN INJURY1 303 9% Front 18% 9% 9% Back 18% 1% 18% 18% Fig. 3.24 \200\230Rule of nines \200\231 (adults). The percentage on each limb refers to t he front or rear aspect. A burn to the whole of the head represents 9% total body surface a rea (TBSA). Reprinted with permission from Greaves I et al. (2005). Emergency care: a textb ook for paramedics, 2nd edn. W.B. Saunders Co. Ltd. CHAPTER 3 Trauma 304