Trauma epidemiology

The most common cause of death from birth to the fourth decade, and the fourth most common cause overall, is trauma. For individuals between 15 and 24 years, trauma leads to three times as many deaths as any other cause. On average, for individuals of working age, heart disease and cancer result in the loss of 10 years of potential life, but road traffic accidents (RTAs) alone cause the loss of 30–35 years. The economic cost is staggering. Patients with trauma occupy 10% of hospital beds and, globally, trauma accounts for 1–2% of gross national product.

However, experience of trauma cannot be extrapolated from other countries to predict events or outcomes. For example, in the UK, RTAs, falls and interpersonal violence account for the majority of major trauma (Fig. 7.1). Fewer than 1 in 10 patients with major trauma have penetrating injury, and this is usually caused by knives. In the USA, approximately 20% of the population owns a gun, and RTA deaths are matched by firearm injuries. Staggeringly, having a gun in the home increases the risk of homicide three-fold, and that of suicide five-fold; and for 15–24-year-olds, these figures increase by a factor of 10. A recent UK study found that the total number of homicides over a 2-year period for a population of 0.8 million was similar to that seen in a single day among the same-sized population of many American cities. In so-called developed countries, annually, 1 person in 50 will be involved in an RTA. Of these, 1% will die, 10% will need hospital treatment and 25% will be temporarily disabled.

Fig. 7.1 Relative proportions of causes of trauma deaths.

(Data kindly provided by the Scottish Trauma Audit Group 1992–1997.)

It is often quoted that trauma deaths have a trimodal distribution. The first ‘peak’, representing deaths occurring immediately after or within a few seconds of injury, contributes up to 50% of the total. The second ‘peak’, up to 4 hours after injury, accounts for 30% of deaths, and the final 20% take place (usually in an intensive care unit) days or weeks after the event. Much significance has been placed upon this alleged temporal relationship, particularly the second peak. On the basis that interventions for the second group of patients offered great potential for preventing unnecessary deaths, the provision and nature of pre-hospital and hospital trauma services in the USA and the UK were changed profoundly. Unfortunately, the ‘second peak’ is a myth, at least in the UK, where the vast majority of deaths occur immediately after or within a very few minutes of injury. Furthermore, the subsequent deaths do not cluster into peaks. So, although attempts to improve care for those who initially survive must continue, the overwhelming message is that trauma prevention is far more important than any other aspect.

Trauma is a common cause of death and morbidity in children. After the first year of life, it is the most common cause of death in the paediatric population. The most common causes of serious injury seen in children are RTAs and falls. Non-accidental injury accounts for a significant number of the remainder.

The pattern of injury seen in children differs from that in adults. The small mass of the child is less able to disperse the kinetic energy of impact; as a consequence, multi-system injury is more common. The large paediatric head (in proportion to the rest of the body) means that head injuries are common. The larger body surface area to body mass found in infants and children results in increased heat loss after injury. There are often significant psychological sequelae to major trauma in children. It has been estimated that as many as 60% of such children are left with behavioural or learning difficulties after a serious accident.

Injury biomechanics and accident prevention

To anticipate the injuries from any given trauma event, the clinician must understand the biomechanics involved. An accurate history can identify or predict the great majority of an individual patient’s injuries.

The magnitude of injury is related to the energy transferred to the victim during the event, the volume/area of tissue involved, and the time taken for the interaction. Tissue characteristics, such as elasticity, plasticity and fluid content, are also important. These factors are summarized in the formula:

where E = energy transfer, T = time, V = volume of tissue, and C = tissue factors (a constant).

Kinetic energy, the energy of motion, is proportional to the mass of the object but to the square of its velocity. This can have unexpected effects. For example, a pedestrian struck by a car of mass 700 kg travelling at 100 km/h receives over three times more destructive energy than if hit by a heavy lorry of mass 5000 kg travelling at 40 km/h. If the car travels at 160 km/h, over 10 times the energy is involved. The longer the time frame during which the kinetic energy is transferred to the body, the less the acceleration/deceleration force sustained and the less the trauma that results.

These physical principles underpin strategies of accident prevention and protection. Obviously, reducing the chance of direct contact helps; separating pedestrians and traffic is the single most important factor in reducing pedestrian injury rates. This is illustrated by the fact that, in the US, less than 2% of traffic fatalities are pedestrians, whereas in the UK they account for 36% of the total. In a similar fashion, the central reservation barriers on motorways dramatically reduce the chances of high-speed head-on collisions (Fig. 7.2).

Fig. 7.2 Car involved in a high-speed, head-on collision, showing the magnitude of structural damage.

If impact does occur, then limitation of the velocities involved is the most important determinant in reducing injury. One in 10 drivers involved in RTAs has been travelling inappropriately fast. Even a 1 mph (1.6 km/h) reduction in average road speed reduces fatal accidents by 8%. The 20 mph (32 km/h) zones in residential areas, together with traffic calming measures, significantly reduce deaths and serious injuries, in particular to children and the elderly.

Contact factors can be minimized by vehicle design: crumple zones, energy-absorbing materials, preventing the ejection of passengers from the vehicle and reducing intrusion into the passenger compartment. For the occupants, seatbelts, airbags, collapsible steering columns and soft fascia compartments enable contact deceleration to take place over a longer time period, reducing the potential for injury (Fig. 7.3). Properly used, seatbelts reduce the risk of death/serious injury by 45%. Airbags further reduce the risk of death by 10% for belted drivers, and by 20% for unbelted front-seat passengers, but may not provide protection from side-impact events, or if the vehicle rolls over.

Fig. 7.3 Impact sites in an unrestrained head-on collision.

These devices can also modify the patterns of injury, particularly if they are incorrectly positioned. Seatbelts and airbags do reduce deaths overall but certain injuries, e.g. sternal fractures and soft-tissue neck injuries, may be associated with their use. If lap belts alone are used, pancreatic, renal, splenic and liver injuries are relatively more common and hyperflexion of the trunk over the belt can produce anterior compression fractures of the vertebrae. Finally, seatbelts are only protective when used. A recent study showed that 90% of all injured rear-seat passengers were unrestrained. These passengers increase the severity of their own injuries, as well as causing injury to restrained individuals in the front seats.

Alcohol and drugs

The message is often unwelcome, but few episodes of trauma are without direct human failing or causation. There is, for instance, a four-fold increase in the risk of being involved in an RTA while using a mobile telephone, even if hands free, a level similar to that seen when driving with a blood alcohol level at the UK legal limit (blood: 80 mg alcohol/ 100 ml of blood; breath: 3g mcg/100 ml breath).

The combination of youthful over-confidence, incompletely developed motor skills, and ready availability of high performance vehicles accounts for an extraordinarily high rate of accidents. These rates decline with age and experience, but at the other end of the spectrum, the elderly have a disproportionately high incidence of trauma because of co-existing medical conditions and visual/motor impairments that affect judgement.

At all ages, alcohol is the major causal factor for all types of trauma; 60% of individuals sustaining trauma in assaults have consumed alcohol. For burns, homicides and drowning, alcohol is implicated in 30–50% of events. Its combination with young males and road vehicles is particularly lethal; in this group, one-third of all fatalities, and 10% of all injuries, involve alcohol consumption. Drink-driving laws do reduce the proportion of fatal crashes involving intoxicated drivers, but high-risk behaviour remains common. Although death rates from alcohol-related events have fallen, the risk of being involved in an accident with a blood alcohol at the current UK driving limit is twice that for an individual with no alcohol in their blood. At higher levels, the risk dramatically increases even further. About 20% of RTA deaths are thought to be related to drug or substance misuse, but the difficulties of testing and the involvement of prescribed medications such as sedatives may mean that this is a considerable underestimate.

Wounds

Gunshot wounds

Gunshot wound data (Fig. 7.4) highlight the gulf between UK and US practice. In the US, deaths from gunshot wounds are the fourth leading cause of years of potential life lost before the age of 65. Guns are used in over 60% of suicides and 70% of all homicides. Non-fatal gunshot wounds outnumber fatal ones two- to three-fold.

Fig. 7.4 Chest X-ray showing a bullet to the right of the upper mediastinum.

(Courtesy of Miss Kate Wilson.)

As with other injury, the exchange of energy is crucial. Low-velocity missiles cause local injury, involving tissue tearing and compression. When velocities exceed 500–600 m/s, cavitation injury – a temporary space torn in tissues at right angles to the direction of travel – is also produced. This process develops in microseconds and, depending upon the body tissues involved and their elasticity, can involve a volume many times the diameter of the bullet itself. The wounding potential can be further magnified by features specifically designed to increase the area of injury and the release of energy; examples include bullets that tumble in tissues and others designed to deform or fragment on impact (dum-dum or semi-jacketed bullets).

Shotgun events are relatively more common in the UK than handgun or rifle injuries (http://www.crimeandjustice. org.uk/). The muzzle velocity of these weapons is relatively high, but dissipation of the shot and air resistance on the pellets quickly decrease their velocity and limit the wounding potential (Fig. 7.5). These weapons are lethal at close range but, unless ‘choked’, are relatively less wounding at greater distances, where they tend to cause superficial injury to skin and subcutaneous tissues.

Fig. 7.5 X-ray of the lower chest and upper abdomen, showing pellets from a shotgun injury.

Note the wide dissipation of the pellets.

Falls

The major determinant of injury and the chance of death is directly proportional to the height fallen, as the accelerating force of gravity is constant. For practical purposes, the velocity at impact (v) is given by the equation:

where g = gravitational constant (9.8 m/s) and h = height fallen in meters

Thus a body falling two storeys (10 m) has an impact velocity of around 50 kph. At impact, the deceleration forces are determined by the individual’s mass, the nature of the landing surface and the body’s orientation on landing. Surfaces such as mud, snow, soft earth and, to a lesser extent, water can permit an increased duration of impact, reducing deceleration forces and hence injury. For an ‘average’ man, a 5 m fall on to a concrete surface produces a deceleration force of approximately 700 g; if the landing is a soft, yielding surface, the stopping distance may be several centimetres, decreasing the force 10–20-fold.

The body’s position during landing affects the contact area and the propagation of energy since, if the same force is dissipated over a larger area, there is less force per unit area and hence less damage (Figs 7.6 and 7.7). Feet-first falls involve a relatively small area of contact, but deceleration forces can be reduced by flexing the knees and hips. Regardless of the position on landing, however, for falls > 5 m there is a high incidence of deceleration injuries to intrathoracic and intra-abdominal structures, particularly where these are relatively immobile or tethered: for example, the aortic root and the mesenteric arteries. Overall, falls on to an unyielding surface from 15–20 m are associated with a greater than 50% mortality. Nevertheless, bizarre descriptions of survival from high falls do exist. There are well documented accounts of individuals surviving after falling from aircraft onto trees and deep snow. Clothing may also play a role in slowing the rate of fall: in 1885, Miss Sarah Ann Henley survived after a fall from the Clifton suspension bridge (∼︀75 m) as her hooped crinolines acted as a parachute and the tide was out so that the landing surface was thick mud.

Fig. 7.6 Lateral view of ankle and grossly comminuted fracture of calcaneum, involving the subtalar joint.

The mechanism of injury was a fall on to the feet from 15 metres.

Fig. 7.7 Compression (wedge) fracture of the L2 vertebral body (arrow), caused by a fall from height.

Injury severity assessment

Audit of trauma patients, both individually and as a group, is essential. To allow objective comparison between systems or hospitals, injury classifications have become standardized.

Two types of classification are used. The first measures the severity of anatomical injury. The most commonly used system is the Abbreviated Injury Scale (AIS). Once the patient’s injuries have all been identified (this may only be possible at discharge or autopsy), each separate injury is assessed from a scoring ‘dictionary’ and awarded a numerical score. The Injury Severity Score (ISS) is then derived from the three highest AIS scores within six body areas (head and neck, abdomen and pelvic contents, bony pelvis and limbs, face, chest and body surface). ISS provides an internationally recognized objective evaluation of anatomical injury.

The second type of classification is physiological. The best-known physiological scoring system is the Glasgow Coma Scale (Table 7.1), which is used to assess the neurological state of injured patients objectively, and which also has prognostic value. The Glasgow Coma score (GCS), in conjunction with two other physiological recordings, systolic blood pressure and respiratory rate, can be used to produce the ‘Revised Trauma Score’. Although widely used, physiological scoring systems have intrinsic problems. Some patients with severe injury may not be identified initially, usually because the assessment has been performed before detectable physiological compromise has had time to occur. The system may also overestimate injury severity if physiological changes occur (due, for example, to alcohol) that are not reflected in the measured parameters, or which modify these factors. In addition, no allowance is made for factors such as comorbid features e.g. underlying cardiac or pulmonary disease or medications.

Table 7.1 Glasgow Coma Scale

The combination of anatomical and physiological scoring systems allows comparisons between predicted and actual patient outcomes; age, and factors such as whether the injury was blunt or penetrating, can also be incorporated. This permits meaningful audit between hospitals and trauma systems. It must be stressed that these comparisons are valid for patient populations and have much less validity if applied to individual cases.

Prehospital care and transport

The objective of prehospital care is to prevent further injury, initiate resuscitation and transport the patient safely and rapidly to the most appropriate hospital. The size and demographics of the population served, along with geographical constraints, affect this directly.

In the USA, basic trauma care is often provided by fire and police services. Emergency medical technicians and paramedics supply advanced care, with direct communication links to the receiving hospital. If their injuries are several or severe, or if there is a significant mechanism of injury, patients may bypass the nearest hospital and be taken directly to a designated trauma centre.

In the UK and Europe, ambulance services, augmented by physician-led teams, often transport the patient to the nearest hospital. Paramedics can provide techniques such as tracheal intubation, peripheral intravenous access, and the administration of intravenous fluids and drugs. Intuitively, the use of such skills by ambulance paramedics at the scene of injury or en route to hospital should improve outcome for injured patients, but controlled studies have not demonstrated this. There are two main reasons for this. First, paramedic treatment may increase prehospital time, delaying definitive care. Such delay is closely related to increases in mortality. Second, the techniques used may themselves have intrinsically adverse effects. For example, intravenous fluids given to patients in whom bleeding cannot be controlled (e.g. intra-peritoneal bleeding, major vascular disruption, pelvic or long bone fractures) can precipitate additional blood loss by increasing blood pressure. Except for situations in which unavoidable delays will occur for a prehospital patient (usually entrapment or impalement, or rural or inaccessible locations), advanced pre-hospital techniques are probably inappropriate and time-wasting.

Transport from accident locus to hospital must be safe and rapid, with constant communication. In the UK, land-based ambulance service vehicles perform this, with additional support from helicopters and fixed-wing aircraft. Much experience has been obtained with helicopters in military medical environments, and in the USA and Australia; they dramatically increase costs and have additional risks for both patient and crew. Despite the potential to reduce journey times, the types of helicopter used in the UK have major operational difficulties with poor visibility, night-time flying, high winds and urban environments. Recent audit in an urban environment in the UK failed to show an improvement in response times, with longer on-scene times and no increase in survival for trauma patients. There is a clear justification for helicopter use in offshore and mountain rescue and in certain rural incident situations, but the majority of patients will continue to be transported by land ambulances.

Trauma centres

A trauma patient should be provided with definitive surgical and intensive care facilities as soon as possible after injury. The problem is how to deliver this standard. In the 1970s and 1980s, trauma centres were introduced in the USA and a few European cities, where they unequivocally reduced preventable, in-hospital trauma deaths. Some of the results were remarkable, with ‘avoidable’ deaths reduced 5–10-fold for patients taken directly to a level 1 centre. The key elements in these systems were: transfer of patients from the accident scene directly to the centre; reception by senior staff on a 24-hour basis; the availability of all appropriate specialties on the same site; and a high throughput of patients.

Independent evaluation of the pilot trauma centre in England, however, failed to show a reduction in death rates. Two facts may explain this disappointing result. The first is the difference in trauma epidemiology, in relation to both the nature of the trauma and the volume of patients presenting. Secondly, despite having run for several years, the centre was not fully integrated into a comprehensive regionalized system (EBM 7.1). For the foreseeable future in the UK, the provision of care will be by a trauma team approach (Fig. 7.8), although reorganization and regionalization of trauma services in some UK areas is developing aspects of trauma centre care (http://www.rcseng.ac.uk/publications/docs/provision-of-trauma-care-1).

Fig. 7.8 Trauma team organization.

Resuscitation in the emergency department

The first 10 minutes

The receiving department should have advance warning from ambulance control to permit an appropriate manpower and resource response. Advance information required by the trauma team includes:

• estimated time of arrival

• number, age and sex of patients

• nature of the incident and any special features, e.g. associated chemical/radioactive contamination, helicopter transportation etc

• brief details of injuries, treatment given at the scene/in transit and current condition.

The resuscitation room must have all the equipment that will be needed for at least the first 1–2 hours of resuscitation. A calm, ordered approach is essential. Compliance with universal precautions for the disposal of sharps/instruments, and the use of gloves, face/eye protection and protective clothing is mandatory. All personnel must be appropriately immunized for hepatitis B.

If the number and severity of injured patients exceeds the facilities immediately available, the hospital’s major incident plan may need to be activated. In this event, patients are triaged on arrival according to their priority for treatment.

During reception, a concise, relevant history is obtained from the ambulance crew and other emergency personnel, noting factors associated with an increased likelihood of severe injury. Digital camera images taken at the accident scene can help the receiving trauma team assess the mechanisms and forces involved and predict likely injuries.

A trauma team, consisting of 4–5 experienced doctors and nurses, is used for the patient’s initial assessment and treatment (Fig. 7.8). Each team member has a pre-assigned role and performs this, unless directed otherwise by the team leader, who must have sufficient seniority and competence to direct and control the entire resuscitation process. The team members must be entirely familiar with the tasks required of them and perform them with minimal delay or questioning.

The patient’s clothing is removed completely (cut off, if necessary, to avoid patient movement), allowing adequate access for examination and to avoid missing an occult external injury. Injured patients lose their normal thermo-regulatory ability, so they must then be kept warm and excessive exposure for examination or practical procedures should be avoided.

A traditional surgical approach, with history taking, clinical examination, investigation and treatment, is inappropriate in major trauma patients. An ‘ABC’ approach is logical and easy to remember, but although the steps are presented here sequentially, the trauma team performs and constantly reassesses all of these aspects simultaneously.

Summary Box 7.2 The primary survey

• Airway with cervical spine control

• Breathing with ventilation

• Circulation with haemorrhage control

• Neurological disability and pupils

• Exposure and environment.

Airway

The patency of the airway is first assessed by direct inspection, identifying and removing obstructions. Loose-fitting dentures or dental plates are removed. Noisy breathing, snoring or stridor implies airway obstruction. A rigid suction catheter, used carefully to avoid stimulation of the sensitive pharynx, will remove blood, vomit, secretions and other debris from the mouth and oropharynx. Larger items, e.g. lumps of food, are extracted with forceps under direct vision.

The most common cause of airway obstruction is a reduced conscious level, with the tongue falling back and blocking the oropharyx. Airway clearance, together with the ‘chin-lift’ or ‘jaw-thrust’ manoeuvres, will correct this in the majority of cases. The airway is then constantly re-assessed by looking (to see the chest rise and fall), listening (for abnormal airway sounds) and feeling (for the patient’s exhaled breath, using the side of the cheek or hand).

Assessment of conscious level helps in airway assessment. A patient speaking in complete sentences does not have an immediate airway problem (although one may develop later). The Glasgow Coma Scale can identify patients with established or potential problems and, if the score is < 8/15, usually mandates early definitive airway intervention, as the protective gag and swallow airway reflexes are likely to be absent or compromised. In the majority of cases, the upper airway is secured with simple positioning, regular suction and the use of basic adjuncts such as oro- or nasopharyngeal airways.

Control of the cervical spine

Irrespective of the airway control technique used, the cervical cord is constantly protected by manual in-line cervical control with the neck in the neutral position, or by using a carefully fitted semi-rigid neck collar, bolsters and tape.

Orotracheal intubation is the advanced airway technique of choice (Fig. 7.9). It protects the airway from aspiration of vomit or blood, and allows ventilation with controlled levels of oxygen and airway suctioning to remove debris. It does, however, require expertise in using anaesthetic and neuromuscular paralyzing agents. Prior to intubation, the patient is pre-oxygenated and must be carefully monitored throughout the process. A ‘surgical’ airway is extremely rarely needed; if one is required, a percutaneous cricothyrotomy is the simplest, safest and quickest surgical approach (see chapter 8).

Fig. 7.9 Rapid-sequence intubation in a trauma patient: note cricoid pressure being applied to prevent regurgitation of stomach contents.

Advanced airway techniques

These are required when:

• protective airway reflexes are absent (usually caused by altered consciousness)

• basic techniques are unable to cope with current or predicted airway compromise (e.g. major facial or burns/inhalation injury)

• there is a need for controlled ventilation (e.g. head and/or chest injury).

Breathing

Optimal ventilation requires a patent upper and lower airway and effective function of the thoracic wall, lungs and diaphragm. Clinical assessment is extremely helpful. Respiratory compromise is characterized by tachypnoea or bradypnoea, the use of accessory muscles of respiration, and paradoxical (see-saw) movement of the chest and abdomen, indicating failure of normal diaphragmatic function. Hypoxia may be manifest by restlessness, tachycardia, confusion, agitation, pallor or sweating. Cyanosis is rare and difficult to detect clinically, particularly if hypovolaemia is present.

Concern about oxygen toxicity in the initial phase of resuscitation is unnecessary. Until the patient is stable and adequate tissue oxygen delivery has been confirmed, the highest possible concentration of oxygen should be administered. Pulse oximeters can detect arterial desaturation, but readings are unreliable in hypovolaemic, shocked patients, in limbs with vascular injury, or if abnormal haemoglobins (including carboxyhaemoglobin) are present. Pulse oximetry does not replace arterial blood gas analysis, as hypercapnoea can occur with normal SpO₂ levels.

Clinical inspection, palpation and auscultation of the neck and chest (including the back) should detect immediately life-threatening injuries such as flail segment, penetrating wounds, tension or open pneumothoraces, major haemothorax and cardiac tamponade. These conditions need immediate treatment, e.g. needle thoracocentesis for tension pneumothorax, or the insertion of an intercostal drain for haemothorax. Open or sucking chest wounds (Fig. 7.10) are rare but, if present, allow equalization of atmospheric and intrathoracic pressures. With large defects, atmospheric air passes through the wound into the intrathoracic space with each inspiration, and the lung collapses. To prevent this, the open wound is covered with a sterile occlusive dressing, taped on three sides. This acts as a flutter valve, and formal tube thoracostomy is then performed at a separate site from the open wound.

Fig. 7.10 Open (sucking) chest wound from a fall on to a metal stake.

Repeated arterial blood gas analyses are needed to ensure that hypoxia is not present and that alveolar ventilation is sufficient to prevent hypercapnoea. For patients who are intubated and ventilated, additional problems may develop. Positive-pressure ventilation may reduce cardiac output (manifest initially by tachycardia ± hypotension) because of decreased venous return to the heart, resulting from increased intrathoracic pressure during the ‘inspiratory’ phase of ventilation. The risk of pneumothorax (Table 7.2) in patients with coexisting chest injuries is markedly increased by positive-pressure ventilation. If a pneumothorax is already present, tension may be induced. For these reasons, tube thoracostomy is mandatory if a pneumothorax is present and positive-pressure ventilation, for whatever reason, is to be undertaken.

Table 7.2 Clinical features of tension pneumothorax

• Cardiorespiratory distress (tachycardia, hypotension) • Distended neck veins • Asymmetric chest wall movement • Hyper-resonant percussion note on affected side • Absent or reduced breath sounds on affected side

For patients in whom positive-pressure ventilation is instituted, the aim is to ensure adequate oxygenation (P_aO₂ levels > 12 kPa) and alveolar ventilation (P_aCO₂ levels ∼︀ 4 kPa). Controlled ventilation is particularly important in patients with head injury, as hypercarbia causes dilatation of the cerebral vessels and increased intracranial pressure, whereas hypocarbia produces cerebrovascular vasospasm, compromising cerebral perfusion.

The drugs needed to permit intubation and controlled ventilation may themselves obscure important clinical features, particularly of neurological or abdominal injury. Before any drugs are used, the patient’s neurological status must be recorded. Additional imaging, such as computed tomography (CT), will be required if there is any suspicion of associated head injury. Abdominal injury is commonly missed in patients with altered consciousness of whatever cause. Clinical signs are modified or absent in paralyzed and sedated patients, and so additional investigations, such as ultrasound, CT or diagnostic peritoneal lavage, are important (see below).

Summary Box 7.3 Common causes of breathing and ventilation problems

• Airway obstruction

• Tension pneumothorax

• Massive haemothorax

• Flail chest

• Open (sucking) chest wound

• Cardiac tamponade.

Gastric dilatation is common in trauma patients. It results from a combination of factors, including air-swallowing (in conscious patients), bag-mask ventilation (where the airway pressure exceeds the gastro-oesophageal closing pressure), and the effects of sympathetic nervous system overactivity and electrolyte disturbance on gastric peristalsis. A distended stomach full of air, fluid and food in a patient with compromised airway protective reflexes is a situation ripe for regurgitation and potentially fatal aspiration. In addition, the distended stomach will restrict diaphragmatic movement and impair respiration. To prevent these problems, a nasogastric tube is routinely inserted and suction applied; if there is any suspicion of an anterior cranial fossa fracture, an orogastric tube is used.

Circulation

The clinical detection of blood loss and the resulting haemodynamic effects is crude and non-specific. Pulse rate, cuff blood pressure and peripheral perfusion (assessed by capillary refill time) are routinely noted every 5–10 minutes in the initial stages, but these recordings have major limitations. Homeostatic mechanisms in previously fit healthy adults mean that, depending upon the rate and site of blood loss, 20% or more of total circulating blood volume can be lost without a measurable change in these recordings. Isolated readings are especially misleading. Trends in pulse rate and blood pressure are of much greater value. A rising pulse rate combined with a falling blood pressure strongly suggests uncontrolled, often occult, blood loss.

Absence of these features does not necessarily mean that all is well. The patient may not be able to respond to hypovolaemia by increasing the heart rate because of age, pre-existing cardiac disease or medications such as β-blockers or calcium channel blockers. In addition, an individual’s ‘normal’ values need to be considered. A blood pressure of 110/60 mmHg may represent severe hypotension if the patient’s normal value is 190/120 mmHg, but may be normal for a healthy young adult. Unfortunately, this knowledge is rarely available in the early stages of resuscitation, and a high index of suspicion, bearing in mind the mechanism of injury, is therefore imperative.

To reduce blood loss is essential. External haemorrhage can invariably be controlled by simple direct pressure. Haemostasis from the sometimes profuse bleeding of scalp wounds is best achieved with carefully applied sutures or staples. Splinting of long-bone fractures reduces blood loss from fracture sites by up to 50%, makes the patient more comfortable, and reduces analgesic requirements (Fig. 7.11). In contrast, blood loss into the peritoneal cavity, thorax or pelvis is usually concealed, can be life-threatening, and cannot be simply controlled. Patients with major pelvic fractures pose a difficult management problem, as conventional splintage is impossible and massive and uncontrollable blood loss may result (Fig. 7.12). The optimal approach is the application of external fixator devices in the resuscitation phase, followed, if required, by angiographic embolization.

Fig. 7.11 Right lower limb in a traction device to provide splintage.

Fig. 7.12 X-ray of the pelvis, showing bilateral upper and lower pubic rami fractures (upper arrow), with ‘butterfly’ fragment and shearing injury affecting the left sacroiliac joint (lower arrows).

Summary Box 7.4 Situations where blood loss may be misappreciated

• The elderly

• Patients on concurrent drug therapy (e.g. β-blockers, antihypertensives, anti-anginals)

• Patients with a pacemaker

• Athletes

• Pregnancy

• Hypothermia.

The next priority is to insert and secure two large-bore (12–14 G) intravenous cannulae. The forearms or antecubital fossae are the most accessible peripheral sites, but the nature and location of the injuries may require alternative sites, such as the femoral or external jugular veins, to be used. Central venous cannulation is difficult and potentially hazardous in shocked hypovolaemic patients, so if percutaneous access cannot be obtained, a surgical cut-down at the saphenofemoral junction is preferable, although more time-consuming. Intraosseous access to long bones in the adult is a viable alternative for initial resuscitation. At the time of cannulation, initial venous blood samples should be taken, carefully labelled and sent for analysis, the laboratories having previously been alerted.

The effective resuscitation of the injured child requires an appreciation of the physiological differences that exist between children and adults. The normal cardiovascular and respiratory parameters vary with age. For example, the normal heart rate of a newborn infant is 160 beats/minute; the normal respiratory rate of a 1-year-old is about 30 breaths per minute. A knowledge of what is normal is required to allow the confident identification of the abnormal.

Suitable equipment is essential to resuscitate children of different ages and weights safely. Cuffed tracheal tubes are not used in small children. Small intravenous cannulae may be necessary and intraosseous needles can be used for vascular access in children. Different-sized cervical collars, oxygen face masks, laryngoscopes and other equipment should be readily available in any resuscitation room receiving children.

Notwithstanding the above, the ABCDE sequence of resuscitation that is followed in the child is the same as that in the adult: airway with cervical spine control, breathing with oxygen, circulation with control of bleeding, disability, exposure.

The choice of fluids for the replacement of traumatic blood loss is controversial and poorly understood. Intravenous volume replacement is begun with infusion of an isotonic crystalloid such as 0.9% saline or Ringer’s lactate. In the UK, after 1000–2000 ml of crystalloid, a colloid is commonly given prior to, or together with, blood. Theoretically, colloids (such as albumin solutions, gelatins, starches or dextrans) might be expected to be more effective, but there is no good evidence to suggest this in clinical practice (EBM 7.2).

7.2 Resuscitation fluid choice

‘There is no evidence from RCTs that volume resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma.’

Perel P, Roberts I. Colloids versus crystalloids for fluid resuscitation in critically ill patients. Cochrane Database of Systematic Reviews 2011, Issue 3. Art. No.: CD000567. DOI: 10.1002/14651858.CD000567.pub4.

Irrespective of the fluid chosen, it must be warmed to 37–38°C before infusion to prevent hypothermia and aggravating coagulation deficits. This is achieved with in-line warming devices that infuse the fluid at the required temperature, regardless of flow rate.

Intravenous fluid administration is initially dictated by the nature of the patient’s injuries, an estimate of the current volume deficit, and the clinical and haemodynamic responses to treatment. Failure to respond to the first 1–2 litres of volume replacement suggests that the volume deficit is great (> 40% of circulating volume). It is, however, inappropriate to correct haemodynamic measurements in isolation, and there are situations where, in the presence of an uncontrolled bleeding site (for example, in the pelvis or peritoneum), increasing blood pressure will simply exacerbate blood losses.

Blood transfusion requirements depend upon the magnitude of blood loss and the physiological response. It is usual to replace losses with the aim of maintaining the patient’s haematocrit at ∼︀30%. Where there is immediately life-threatening haemorrhage, group O Rhesus-negative blood is given, but more usually fully cross-matched or type-specific blood can be supplied. Most transfusion services supply packed red cells. There is no evidence that ‘fresh’ whole blood is preferable. In situations of massive blood loss, where replacement of more than the equivalent of one circulating blood volume is needed, coagulation problems should be anticipated. Military experience has led to development of massive transfusion guidelines including early use of platelets and coagulation factors, often directed by ‘near-patient’ testing of coagulation. Recently, tranexamic acid (an antifibrinolytic agent) has been shown to improve morbidity and mortality in trauma patients at risk of major bleeding (EBM 7.3). Close liaison with the Blood Transfusion Service and haematology laboratories is essential for optimal management.

7.3 Antifibrinolytic treatment

‘Uncontrolled bleeding is an important cause of death in trauma victims. Antifibrinolytic treatment with tranexamic acid (TXA) reduces mortality in bleeding trauma patients without increasing the risk of adverse events although further trials are needed to determine its efficacy and safety in isolated traumatic brain injury.’

Roberts I, Shakur H, Ker K, Coats T, on behalf of the CRASH-2 Trial collaborators. Antifibrinolytic drugs for acute traumatic injury. Cochrane Database of Systematic Reviews 2011, Issue 1. Art. No.: CD004896. DOI: 10.1002/14651858.CD004896.pub3.

Summary Box 7.5 Initial blood samples in the trauma patient

• Blood grouping and cross-matching

• Full blood count and haematocrit

• Urea and electrolytes

• Plasma glucose

• Arterial blood gases

• Kleihauer–Betke analysis (in pregnant patients).

Measurement of urine output (> 1 ml/kg body weight/hr normally implies adequate renal perfusion), continuous intra-arterial blood pressure monitoring and serial lactate levels assist in monitoring the response to infusion. In this situation, intra-arterial blood pressure monitoring is significantly more accurate than standard cuff methods, and has the additional advantage that the in-dwelling cannula permits regular arterial blood sampling without additional patient discomfort. Continuous electrocardiogram (ECG) monitoring, oxygen saturation SpO₂ (by pulse oximetry), core temperature and serial blood pressure measurements are standard requirements and augment clinical judgement. A low or falling GCS may indicate cerebral hypoperfusion due to hypovolaemia or worsening intracranial injury. More sophisticated means of cardiovascular assessment can provide additional information and should be used at an early stage, but techniques such as central venous and pulmonary artery wedge pressure and cardiac output measurement are usually impracticable in the immediate resuscitative phase. They will be used later, particularly if vasoactive agents such as vasopressors or inotropes are employed.

Summary Box 7.6 Monitoring the trauma patient

• Heart rate

• Blood pressure (cuff and intra-arterial) (in both arms if suspected aortic injury)

• Capillary refill

• Respiratory rate

• Glasgow Coma Scale

• Urine output

• ECG

• Pulse oximetry

• Core temperature.

Analgesia

A calm, gentle and reassuring approach does much to relieve anxiety and is the first step in pain relief. Adequate analgesia is often neglected – or worse, thought to be unnecessary or hazardous in trauma patients. Physiological responses to pain produce adverse effects – for example, by increasing intracranial and arterial pressure – and so analgesia is essential. Further, it must be given according to the patient’s individual requirements, rather than as a rigid process.

In cooperative, fully conscious patients without respiratory problems, Entonox (50% nitrous oxide, 50% oxygen) is useful for short-duration procedures such as manipulation of dislocations and fractures. Its value is limited by the need for patient cooperation (the euphoric effect may be associated with confusion and disorientation), its short duration of action and its limited analgesic effect.

Opioid drugs such as morphine or diamorphine, given in small intravenous (intramuscular absorption may be poor and inconsistent) doses titrated to effect are unsurpassed for analgesia. Provided the drug is given like this, haemodynamic disturbance or respiratory depression is rare and the need for antiemetics e.g. cyclizine uncommon. The newer synthetic opioids have no advantages.

Head injury or suspected head injury is not an absolute contraindication to opioid administration, provided that the agent is given as above and that the patient’s airway, ventilation and haemodynamic status are carefully monitored. If necessary, naloxone can be given, if there is doubt as to whether alterations in conscious level are due to the opioid or to the head injury and its effects.

Local anaesthetic techniques are generally of limited value in the early management of major trauma, but an exception is the use of a femoral nerve block for patients with femoral shaft fractures. Long-bone fractures need to be immobilized to reduce pain and blood loss from the fracture site, to facilitate the taking of X-rays, patient movement and transfer, and to reduce the chances of fat embolism syndrome. Inflatable or foam-cushioned splints are suitable for upper-limb or below-knee injuries; adjustable traction splints are best for femoral fractures.

Fig. 7.13 Sensory dermatomes.

Any decrease in the patient’s conscious level (i.e. a numerical fall in GCS) must prompt an immediate search for, and correction of, a primary cause, such as intracranial haematoma, or secondary factors such as hypoxia, hypercarbia, hypotension or hypoglycaemia. Confounding factors may render the assessment of the GCS difficult, especially if the patient has taken alcohol or other drugs, but altered consciousness or other neurological deficit should never be assumed to be due solely to alcohol or other drugs alone until proven otherwise.

Imaging and other diagnostic aids

The radiological investigations needed in the initial phase of the management of a major trauma patient are limited but important. It is important to obtain the best-quality views, and fixed overhead X-ray facilities in the resuscitation room itself are invaluable, as transfer of the patient to a main X-ray department can be hazardous. A portable machine brought to the resuscitation room is preferable to transfer, although the images obtained will be of poorer quality.

There are three primary X-ray views in the blunt trauma patient, but these do have limitations:

Fig. 7.14 Chest X-ray showing rib fractures and subcutaneous emphysema.

Fig. 7.15 Lateral X-ray of the cervical spine, showing C4/5 subluxation (arrowed).

The use of additional imaging techniques depends upon their availability and the clinical state of the patient. For head, spinal and pelvic injury, CT is unsurpassed and rapid. In contrast to the information provided by conventional skull

X-rays (Fig. 7.16), CT defines the nature and magnitude of the intracranial insult (Fig. 7.17). It is therefore invaluable in providing the information the physician needs to determine the requirement for neurosurgical intervention (EBM 7.4).

Fig. 7.16 Lateral X-ray of the skull, showing a fracture.

Fig. 7.17 Computed tomography in head injury.

A Right-sided extradural haematoma (arrows) with midline shift towards the left. B Left-sided subdural haematoma (arrows).

In experienced hands, ultrasound examination of the abdomen is a quick, non-invasive and accurate method of detecting free intraperitoneal fluid. It can be performed in the resuscitation room and has largely supplanted diagnostic peritoneal lavage, although this technique remains a simple and rapid method for establishing the presence of intraperitoneal bleeding if ultrasound is not available. Injury to some solid organs, the retroperitoneum and hollow viscera is less easily demonstrated on ultrasound, and CT – with contrast as necessary – is preferable, provided that the patient is stable and can be transferred safely to the CT suite.

After the resuscitation room

The immediate aim of the resuscitation team is to assess and treat life-threatening injuries. There is no absolute guide as to the length of time this process will take, but the procedures and referral must be performed expediently, without compromising patient care. The result should be a patient with a patent airway and adequate gas exchange, whose circulatory status is normal or in the process of being adequately corrected. Long-bone fractures should have been splinted appropriately and cervical spine control maintained throughout.

Continuing care then involves identifying the correct destination for the patient. The nature and extent of the injuries and the patient’s physiological response to treatment dictate this. In some situations, it is impossible to ‘stabilize’ the patient without immediate surgical intervention. Examples include patients with exsanguinating intra-abdominal or intrathoracic haemorrhage, in whom immediate laparotomy or thoracotomy is mandated.

More commonly, the patient is, at least temporarily, stable so that further investigation can be undertaken beyond the resuscitation room prior to definitive surgical or intensive care unit admission. Senior anaesthetic and surgical staff must accompany the patient in these situations, so that, if sudden deterioration occurs, the patient can be transferred directly to theatre. Full monitoring and resuscitation equipment is mandatory for the transfer.

The subsequent destination of the patient then depends upon their overall condition and the findings of these investigations. Intensive care admission is required if ventilation is needed or anticipated, if there are multiple injuries involving main systems, or if the patient needs invasive monitoring. Stable, self-ventilating patients with less severe injuries may be managed in a high-dependency unit, but the attending staff must be familiar with multiple trauma assessment and the relevant specialties must liaise closely to ensure a multidisciplinary approach. Previous or underlying medical conditions may play a crucial part in the subsequent course of the patient’s course. The role of conditions such as coronary artery disease, diabetes etc. (and the medications required for these conditions) are well established. It is becoming increasingly recognized, however, that changes in immune function after injury may lead not only to local bacterial infections, but also to reactivation of diseases such as malaria which may compromise recovery.

It may be necessary to transfer the patient to another hospital for emergency investigation not available in the receiving hospital, or as part of definitive treatment by a specialist service. Inter- and intrahospital transfer is hazardous and must be performed by experienced anaesthetic and nursing staff with relevant monitoring and resuscitation equipment. The aspects of airway, ventilation and circulation control must be secured prior to transfer. The receiving unit must be informed of the relevant patient details, allowing it to prepare effectively for his or her arrival. The notes, details of investigations, X-rays, scans and observation charts must accompany the patient. The type of transport used will depend upon the distance and geography of the journey involved, but may involve air transportation with all its attendant specific considerations. Regular updates should be supplied to the receiving specialist.