Clinical Review ABC of emergency radiology

Major trauma

BMJ 2005; 330 doi: http://dx.doi.org/10.1136/bmj.330.7500.1136 (Published 12 May 2005) Cite this as: BMJ 2005;330:1136
  1. Otto Chan,
  2. Alistair Wilson

    Introduction

    Advanced trauma life support is the standard method for the initial management of severely injured patients. The principle is simple—treat the greatest threat to life first. Loss of airway will kill before inability to breathe, and inability to breathe will kill before bleeding and loss of circulation. A definitive diagnosis is not necessary to treat the patient initially. The most important point to remember is that no harm should be done to the patient during treatment. The management of severely injured patients is divided into the primary and secondary survey. This article deals with the imaging during the primary survey.

    ABCDE of trauma

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    Primary survey

    The primary survey comprises a rapid evaluation of the patient, resuscitation, and institution of life preserving treatment. This process is called the ABCDE of trauma. Adjuncts to the primary survey include relevant imaging during resuscitation and re-evaluation.

    In practice, most of the steps of the ABCDE are carried out simultaneously by a trauma team. Anaesthetists will usually deal with the airway and intravenous access while the surgeon evaluates the chest, abdomen, and pelvis for potential life threatening injuries.

    Figure1

    Supine radiograph showing endotracheal tube 5 cm above carina (arrow)

    Imaging is requested as part of the primary survey while the patient is assessed, life threatening injuries are dealt with, and resuscitation procedures instituted. Imaging should not be performed if it interferes with the rest of the primary survey or definitive care, and only investigations that may have a direct effect on the patient's initial problems should be done.

    Examples of imaging done as part of the primary survey include radiographs of the supine anteroposterior chest, supine pelvis, and lateral cervical spine (although this can be delayed if necessary); and limited ultrasonography (also known as FAST, focused assessment with sonography for trauma)

    Airways and cervical spine control

    The airway should be assessed for patency. Foreign bodies and vomit should be removed and facial, mandibular, tracheal, and laryngeal injuries should be excluded clinically.

    Figure2

    Radiograph of supine pelvis may be requested for the primary survey. This radiograph shows no abnormality

    If the patient is conscious and talking, there is usually no immediate need for airway intervention. If the patient is unconscious and breathing spontaneously, an oropharyngeal airway may suffice as a temporary measure. Any patient who has a head injury and a score on the Glasgow coma scale of 8 or less should be intubated. However, intubation may be required for optimal control of airways in patients with higher scores.

    If the patient has been intubated, a chest radiograph should be taken to check the position of the endotracheal tube. The tip of the tube should not lie below the level of the aortic arch in a supine chest radiograph and a minimum of 3.5 cm (and preferably 5 cm) above the carina.

    Care should be taken to avoid worsening a potential cervical spine injury while establishing and safeguarding an airway. If the airway has been secured and the neck immobilised the cervical spine radiograph can be delayed. The cervical spine should be immobilised with a cervical collar, sandbag, and tape. Should the collar need to be removed, an experienced member of the trauma team should carry out in-line manual immobilisation of the head and neck.

    Breathing and ventilation

    A patent airway does not guarantee adequate ventilation. The lungs, chest wall, and diaphragm must be assessed for potential injuries that could compromise ventilation acutely. These injuries include tension pneumothorax, tension haemothorax, flail chest, and open pneumothorax. It can be difficult to exclude these injuries in a patient with multiple trauma. A chest radiograph must be taken as soon as possible. If the patient is subsequently intubated or ventilated, a second radiograph should be taken to confirm that the endotracheal tube is in a satisfactory position and that life threatening injuries have not been made worse. Ventilation can cause a simple pneumothorax to become a tension pneumothorax.

    Figure3

    Opaque left haemothorax with evidence of contralateral shift of the mediastinum

    Circulation and haemorrhage control

    The patient's haemodynamic state must be assessed quickly and accurately because bleeding is a major cause of preventable death. Clinical evaluation is essential, in particular, the level of consciousness, skin colour, and pulse. Any external source of bleeding should be identified and dealt with immediately using manual pressure. When the examination or history suggests internal injury, a pelvic radiograph should be taken and limited ultrasonography (FAST) done to exclude hidden blood loss.

    Main causes of hidden blood loss

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    FAST can be performed by a physician, surgeon, or radiologist and has been shown to be valuable in the assessment of blunt trauma patients in the emergency room, especially in unstable patients with multiple injuries. Ultrasonography should be performed in five areas. These areas are the 5 Ps—perihepatic, perisplenic, and pelvis in the abdomen, and pericardial (to exclude a pericardial tamponade) and pleural (to detect fluid or a pneumothorax or consolidated lung) in the chest. The presence of a pelvic fracture or free fluid on ultrasonography mandates a specialist opinion.

    Glasgow coma scale score

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    Disability (neurological examination)

    The patient's neurological state is assessed with the Glasgow coma scale. It is easy and quick to use and is a determinant of patient outcome and possible further management.

    All patients with a head injury should have computed tomography of the head, especially if they have lost consciousness, have amnesia, or severe headaches. Up to 18% of patients with mild head injuries (Glasgow coma scale 14-15) have abnormalities on computed tomography, and 5% of these patients may require surgery.

    Figure4

    Extradural haematoma and a subtle subdural haematoma (left), subdural haematoma (middle left), diffuse axonal injury (middle right), and combination injuries (right)

    If the patient has a head, scan it—missing a serious head injury may have catastrophic consequences

    Computed tomography should be done as soon as possible because morbidity and mortality rises substantially if surgery is delayed. The intracranial findings of computed tomography may include no abnormality, extradural haematoma, subdural haematoma, contusions and intracerebral haematomas, subarachnoid blood, diffuse axonal injury, and combination injuries.

    Fig 1
    Fig 1

    Supine anteroposeterior radiograph of normal chest with ABCDEs interpretation

    The National Institute of Clinical Excellence (NICE) introduced UK guidelines for management of head injury in 2003 that support the advanced trauma life support guidelines. They emphasise that computed tomography must be done within an hour of the patient arriving at the hospital.

    Exposure and environment

    The patient should be fully exposed (by cutting off all clothes) to allow a full examination. It is, however, critical to keep the patient warm with blankets and a heated emergency room. Large volumes of fluids may be infused, and these intravenous fluids should be warmed.

    Adjuncts to primary survey and resuscitation

    As a minimum, patients should have electrocardiography, their blood pressure monitored, pulse oximetry, a nasogastric tube, and a urinary catheter. Blood gases should also be monitored. If a fracture at the base of the skull is suspected, the nasogastric tube can be inserted after computed tomography of the head or an orogastric tube placed.

    ABCs interpretation of pelvic radiographs

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    Interpreting primary survey images

    All imaging must be supervised and done without fuss or undue delay and with meticulous technique. Attention to detail is essential. In particular, the film must be labelled (including the patient's name and a side marker).

    Interpretation of the supine chest radiograph (ABCDEs)

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    The supine chest radiograph should be taken as soon as possible after the patient has been exposed and centred correctly. Attention must be paid to stop patients being rotated and keeping them in the middle of the trolley.

    Figure6

    Radiograph of supine pelvis showing ABCDEs interpretation

    This article is adapted from the 2nd edition of the ABC of Emergency Radiology, which will be published in the autumn

    Alistair Wilson is consultant in accident and emergency medicine and Michael Walsh is consultant surgeon at Royal London Hospital, London.

    The ABC of Emergency Radiology is edited by Otto Chan, consultant radiologist, Royal London Hospital, London (zaideotto{at}blueyonder.co.uk ).

    Footnotes

    • Competing interests None declared.