Major trauma

Published on 11/04/2015 by admin

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Major trauma

PRE-HOSPITAL ASSESSMENT AND INTERVENTION 

PRELIMINARY HOSPITAL MANAGEMENT OF MULTIPLE AND SERIOUS INJURIES 

ABDOMINAL INJURIES 

CHEST INJURIES 

VASCULAR TRAUMA 

ORTHOPAEDIC TRAUMA 

PAEDIATRIC TRAUMA 

Introduction

Major trauma is a relatively rare event in the UK but much more common in other parts of the world, some with higher rates of road traffic collisions (e.g. Saudi Arabia) and others higher levels of personal violence (e.g. South Africa, parts of the USA). Nevertheless, major trauma is the most common cause of death in young people almost everywhere.

For victims who survive the immediate trauma, there are two periods with a particularly high risk of death. The first occurs during the first or ‘golden’ hour after the accident and the second over the next few hours. Survival in the golden hour depends on the severity of injury, the competence of immediate care and the speed of transfer to an accident unit (in the UK, the average time to transport a non-trapped trauma victim to hospital is a surprising 57 minutes). Deaths after the first hour are for the most part avoidable, being largely caused by treatable conditions.

Pre-hospital assessment and intervention

Introduction

The golden hour concept comes from US war experience, popularised by Dr R. Adams Cowley. More recently, following the conflict in Afghanistan, this has been expanded to include the ‘platinum 10 minutes’ during which immediate interventions, particularly in haemorrhage control, may be key determinants of patient survival. Injuries with substantial internal or external bleeding lead to rapid circulatory decompensation; the only effective treatment is expert shock management and surgical arrest of bleeding. Thus, shortening the interval between injury and treatment gives the best chance of survival. The key is rapid essential care at the scene and swift transport to a trauma centre. This strategy is known as scoop and run, as opposed to stay and play, which is best for less severe cases; in these, the risk of physiological derangement caused during transport may be greater than extending the period before hospital treatment.

Assessment at the scene of a road traffic collision

‘Reading the wreckage’ used to foretell patterns and severity of injury to passengers. However, modern cars have sophisticated crumple zones and major vehicle distortion may not cause severe injury, though severe injuries can occur with minor damage. The worst injuries tend to occur in head-on collisions or those affecting the front corners. Some estimate can also be made of whether there was a high- or low-velocity impact. If passengers were killed or thrown out, this indicates a high-velocity impact. Points to check include whether head restraints were in place, whether seatbelts were worn and whether airbags were deployed. For motorcycle crashes, it is best to assume that all victims have pelvic fractures until proved otherwise. When a pedestrian is hit by a car, a ‘bullseye’ fracture of the windscreen indicates a likely severe head injury.

Obvious injuries (e.g. traumatic amputations) are sought in the victims and their level of consciousness and mobility assessed. Trapped wounded need special treatment as they often have long extrication times and need analgesia, intravenous fluids and perhaps sedation to aid release. Trapped patients can quickly become hypothermic and hypovolaemic (see Fig. 15.1).

Pre-hospital care

The guiding principle for the emergency field team is rapid transfer to an appropriate hospital; pre-hospital interventions are limited to essentials. A need for endotracheal intubation is the main intervention to delay transportation but occasionally anaesthetising the patient buys time before direct transfer to a specialised unit.

Airway and breathing: The airway must be assessed and secured first, whilst ensuring the cervical spine is immobilised. If the patient can speak, assume the airway is patent, ventilation is intact and the brain adequately perfused. Agitation, however, may be a sign of hypoxia. In an unconscious or semi-conscious patient, the airway can usually be temporarily secured with a jaw thrust. If tolerated, the patient should then have two nasopharyngeal airways and a Guedel oropharyngeal airway placed to maintain airway patency. Endotracheal intubation is needed if there is inability to maintain or protect the airway or to provide adequate ventilation (Box 15.1). If this proves unattainable, a useful rescue technique is to insert a laryngeal mask (LMA), as used in general anaesthesia; this may avoid the need for a surgical airway. As a last resort, an airway can be achieved using a needle or surgical cricothyroidotomy. In all seriously injured patients, high-flow oxygen therapy (15 L/min) is mandatory.

Box 15.1   Indications for immediate intubation and ventilation following a head injury or multiple injuries

Circulation: Two large-bore intravenous cannulas should be inserted. Initial fluid resuscitation should be based upon injuries sustained and physiological parameters. More recent studies indicate that permissive hypotension is often a better strategy than the previous recommendation of rapid indiscriminate crystalloid infusion. If organ perfusion can be maintained, there are advantages in keeping the pressure low in trauma patients. Physiological compensation is effective at systolic pressures between 70 and 85 mmHg, and cerebral perfusion and urinary output are well maintained. Above this pressure, fresh clot is often dislodged (‘pop a clot’) and then bleeding recurs. A further disadvantage of unnecessary fluid resuscitation is that infusing just 750 ml of crystalloid activates cytokines and causes dilutional coagulopathy.

If a patient is unconscious without a palpable radial or pedal pulse, 250–500 ml of fluid is given immediately, followed by small boluses, repeated only until the point at which a pulse returns. This is titration by pulse and has been successfully employed in major trauma and in military campaigns. If intravenous access is unsuccessful, EZ-IO devices (Fig 15.3) are a quick way of inserting a cannula into bone marrow. Procoagulant agents such as tranexamic acid and activated factor VII are increasingly being used early to reduce blood loss following trauma. If a patient is conscious and orientated or unconscious but has a palpable radial pulse, this indicates a systolic of above 90 mmHg and fluid resuscitation is not started.

Preliminary hospital management of multiple and serious injuries

Organisation of the accident department

Every accident department should have a major disaster plan (Box 15.2). For any major trauma, the field team or ambulance service informs the receiving trauma unit about the impending arrival of seriously injured patients, plus an estimate of numbers and the nature and severity of injuries. This alerts the surgical and anaesthetic teams to be ready when the patients arrive (Box 15.3). Trauma units have a resuscitation room (see Fig. 15.4) with all necessary equipment so infusion sets can be prepared and drugs laid out.

Box 15.2   Major disaster planning

Major disaster plan—receiving hospitals need a detailed (and rehearsed) plan for disasters with many casualties (e.g. train or air crashes). Action cards given to nominated staff summarise this when a major disaster is declared.

The plan defines precisely:

Box 15.3   Major trauma team

Triage is the process of sorting patients into ‘priority of treatment’ groups on arrival to enable efficient use of resources. The usual categories are shown in Table 15.1.

Success in managing patients with life-threatening multiple injuries depends on good organisation. It involves concurrent activity between several professionals but with one person, often the surgeon, designated team leader. The team leader takes overall medical responsibility as well as coordinating all clinicians.

Initial care in the accident department

When seriously injured patients reach the resuscitation room, the golden hour peak of deaths has passed. The main danger of death is from hypovolaemia (intrathoracic or intraperitoneal haemorrhage, blood loss from fractures) or from an expanding intracranial haematoma.

Immediate priorities after reaching hospital are:

Training has been standardised through Advanced Trauma Life Support (ATLS) courses, originally from the American College of Surgeons and now run in many countries. ATLS principles are simple—the greatest threats to life must be treated first. Mortality at this stage following major trauma is now recognised as associated with three key pathophysiological changes termed the ‘lethal triad’ and comprising coagulopathy, hypothermia and acidosis. Damage control resuscitation has emerged as a means of directly minimising these changes, the key components of which are outlined in Box 15.4.

Box 15.4   Damage control resuscitation

Assessment of the seriously injured patient: Despite the urgency, primary assessment must be performed systematically as soon as the patient arrives. The primary survey includes a rapid evaluation, resuscitation and crucial life-preserving treatment. Priorities are summarised in Figure 15.5. Meanwhile, regular monitoring takes place (Box 15.5).

Box 15.5   Monitoring the multiply injured patient

A rapid history is taken whenever practicable, often alongside the secondary survey. A useful mnemonic for this is AMPLE:

Other elements of history come from the field team’s notes and include:

Conscious patients with suspected cervical spine injuries should be moved with extreme caution and no passive movements attempted. The patient should perform active movements; spasm or pain restricts movement in significant injury. To examine the back and perform a rectal examination, the patient should be ‘log-rolled’ by several people.

A secondary survey then assesses the potential for life-threatening problems or complications, although urgent initial treatment may delay this. The key clinical features are given in Figure 15.6; individual systems are described later. Up to 20% of multiple injury patients have injuries missed in the early stages so the secondary survey must be repeated.

X-rays and other investigations: In major trauma, the cervical spine (see below, Fig. 15.10), chest and pelvis are X-rayed in the resuscitation room. The chest films must be good enough to exclude major chest wall, mediastinal and lung injuries and provide a baseline if the patient later deteriorates. Polytrauma patients, or patients with serious head injury should have rapid assessment and stabilisation before swift transfer for trauma CT scan. Patients should not be moved to the CT scanner until they are stable—the machine is known as the ‘donut of death’ in ATLS parlance.

Focused abdominal sonography for trauma, or FAST (see Abdominal injuries, below), is performed in the emergency department for suspected abdominal injuries and bleeding. Initial blood tests include haemoglobin and group and cross-match or antibody screen and ordering of an appropriate amount of blood. In a desperate emergency, universal donor blood (group O, Rh negative) can be transfused. Evidence from recent conflicts has demonstrated the advantages of early administration of blood products in reducing the risk of haemodilution and coagulopathy. Emergency departments are increasingly using ‘blood packs’ which include several units of packed red cells, fresh frozen plasma and platelets. These may be transfused in a 1 : 1 : 1 ratio or in a goal-directed manner, guided by coagulation testing and thromboelastography. Plasma electrolytes and glucose are measured, plus arterial blood gases if there is suspicion of respiratory failure.

Abdominal injuries

Introduction

Abdominal and thoracic injuries often coexist, so it is logical to think in terms of torso trauma. Major torso injuries are a common cause of death at the trauma scene, for example from avulsion of the thoracic aorta, cardiac injury or massive liver injury. Immediate diagnosis and urgent laparotomy or thoracotomy offers almost the only hope of survival, but the injury is often too extensive or time too short to intervene.

The site and signs of external injury provide clues to internal injuries. This is obvious with penetrating injuries but is also true of blunt injuries. For example, trauma to the left upper abdominal quadrant or lower ribs is often coupled with splenic rupture; similarly for the liver with right-sided injuries. Lower abdominal injuries may injure the bladder, and loin trauma the kidney. Central anterior chest trauma can damage the heart whilst clavicular area injury may traumatise the brachial plexus or subclavian blood vessels.

Abdominal injuries are rare compared with head and chest injuries and mortality can be low with prompt and appropriate management. When death occurs, it is usually from massive haemorrhage arising from bursting of liver or spleen or from penetration of major arteries or veins, particularly with gunshot wounds. Note that unrecognised injuries are the principal avoidable cause of death.

Areas of the abdomen other than the main peritoneal cavity may be wounded; pelvic viscera lie within a bony cage but extend low enough to be injured by buttock or perineal wounds. Similarly, retroperitoneal viscera may seem protected but are vulnerable to flank or back wounds, or to deep anterior stab wounds or any gunshot wounds. This area is not easily palpated and diagnosis requires cross-sectional imaging.

Overall, 20% of patients with closed abdominal trauma require operation. In penetrating injuries, 30% with stab wounds require operation and close to 100% of those with gunshot wounds.

Diagnosis of abdominal injuries

Clinical diagnosis is unreliable in blunt injuries because overt signs of bleeding or hollow viscus perforation may not develop until hours after injury. If the patient is stable but the accident involved high energy transfer or other significant injuries are present, early CT scanning should be performed.

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