Recent Advances: Teaching in accident and emergency medicine: 10 commandments of accident and emergency radiologyBMJ 1995; 310 doi: https://doi.org/10.1136/bmj.310.6980.642 (Published 11 March 1995) Cite this as: BMJ 1995;310:642
- Robin Touquet, consultant in accident and emergency medicinea,
- Peter Driscoll, senior lecturer in accident and emergency medicineb,
- David Nicholson, consultant radiologistb
- Correspondence to: Mr Touquet.
- Accepted 12 December 1994
One of the many attractions of accident and emergency medicine is the wide and varied opportunities it provides for education. This is because of the acute nature of the work, which necessitates prompt and accurate decision making. However, in many instances the decisions have to be made by inexperienced senior house officers. Departments therefore need a safe system of practice that can be remembered and adhered to under stress. The 10 commandments is one such system for analysing emergency radiographs of all the regions of the body. This system lays down guidelines to protect both staff and hospitals from the inevitable mistakes that inexperienced doctors will make.
More than half the patients attending accident and emergency departments in the United Kingdom have a radiograph taken. But radiological interpretation can be poor—for example, in one study 39% of clinically important abnormalities were missed by accident and emergency senior house officers.1 In addition points dealing with radiology are involved in over half of all cases of litigation concerning the standards of care in accident and emergency departments (Brian Capstick, personal communication). It is therefore essential to improve the training of senior house officers in interpreting emergency radiographs.
Many accident and emergency departments now run induction courses for junior doctors.2 When teaching emergency radiology, however, it is easy to go over several “radiological pitfalls” and end up simply showing mistakes that have been made by previous incumbents. This only increases anxiety as the doctors realise the multitude of possible errors. It is better to formulate a system that will enable senior house officers to detect abnormalities, to use a book constructively for reference,3 and to know when to ask for help.4 5
This article provides a system that is applicable to doctors of all specialties who request and review emergency radiographs. Use of the 10 commandments will make mistakes much less likely and when mistakes do occur everyone following the system will, to a large extent, be protected from litigation.
1. Treat the patient, not the radiograph
It is essential to understand both the injury and its natural course. If the condition is immediately life threatening treatment should be started straight away without waiting for a radiograph to confirm the clinical diagnosis. Two examples of such conditions are a tension pneumothorax and a severely displaced fractured ankle, where the skin is at risk from hypoxia and fracture blisters.6
The diagnosis of certain injuries is dependent on the clinical findings (box). In such cases the radiograph does not provide the diagnosis but excludes other abnormalities. Even if no radiological abnormality is found the appropriate treatment based on the clinical findings should be started.
In some situations it is difficult to obtain a history and examine the patient, and even more difficult to obtain radiographs of adequate quality—for example, a drunk patient. Nevertheless, the doctor will be blamed for missing a diagnosis if the patient suffers resultant harm.7 Under these circumstances the most serious clinical diagnosis must be considered and appropriate action taken. Drunk patients with a head injury require a minimum of active observation, with prompt computer tomography if marked clinical deterioration occurs. Patients with more minor injuries who can go home safely should be asked to attend the accident and emergency review clinic for reassessment of the injury and possibly radiography. For drunk patients it may well be appropriate to refer them to an agency for alcohol abuse.8
Examples of conditions whose diagnosis relies mainly on clinical findings
Fracture of the base of the skull
Epiphyseal injuries—for example, Salter-Harris type I without shift
Pulled elbow of a toddler
2. Take a history and examine the patient before requesting a radiograph
It is important to consider the patient as a whole and not just the most obvious symptom or sign. Before requesting a radiograph you should establish the mechanism and force of injury and use this information to deduce which resultant abnormalities are likely.6
When examining a seemingly isolated injury, you should be aware of likely associated injuries (box). Trauma victims with multiple injuries present particular difficulties. Standard practice is to take radiographs of the lateral cervical spine, chest, and pelvis in the resuscitation room.5 If the secondary survey (the head to toe detailed examination) is not completed or the necessary views cannot be carried out in accident and emergency, such omissions must be recorded in the patient's notes.
Examples of associated injuries
Head injury with diminished level of consciousness—cervical spine injury
Pain in arm—nerve root entrapment in the neck
Colles' fracture—concomitant fracture of radial head
Pain in the knee—slipped femoral epiphysis
Ankle injury—fracture of styloid process of fifth metatarsal
3. Request a radiograph only when necessary
A useful investigation is one whose result (positive or negative) will alter the patient's management; many requested investigations do not.9 This discipline is delineated systematically in the ABC of Emergency Radiology,3 but the following are common examples where radiographs may be requested unnecessarily: trauma to the coccyx9; a clinically fractured nose (management depends on appearance, the presence of a septal haematoma, and the position of the septum)3 10; skull radiographs in patients with a head injury who require computed tomography of the brain.
In addition, for patients with fractured ribs, a chest radiograph is appropriate only to detect abnormalities to the underlying soft tissues.3 11 Oblique rib views requested solely to determine if and where a rib is fractured are inappropriate because they will not necessarily show the fractured rib. Providing that there is no underlying injury, even if a fractured rib is identified the management of the patient will not be altered.12
A supine radiograph of the abdomen in isolation has few indications, although two are an ingested sharp or pointed foreign body13 and penetrating injury.14 Gas under the diaphragm is best shown in an erect chest radiograph, but in 30% of perforations no free gas is visible even when the patient has been kept erect for 5 minutes to allow free gas to rise.3 11 If immediate radiological reporting in the accident and emergency department is possible a supine film alone may safely enable the correct management decision to be made. However, without radiological training it is unreasonable to expect a young doctor to be this skilled in image interpretation.11 Consequently accident and emergency departments must have protocols and guidelines for senior house officers to follow. In suspected cases of intestinal obstruction or perforated viscus supine and erect (or a lateral decubitus) plain abdominal views may therefore need to be taken.
4. Never look at a radiograph without seeing the patient, and never see the patient without the looking at the radiograph
Irrespective of grade or experience, you should always insist on seeing the patient when asked to interpret a radiograph.6 This is particularly important when patients are transferred to the care of another medical team or handed over at the end of a shift. The receiving doctor can then correlate the radiological findings with the clinical examination, which helps to reduce the chances of missing an abnormality or perpetuating an error (fig 1). If a patient reattends always look at any radiographs taken previously, or at the least obtain the radiologist's report. Do not accept the accident and emergency radiological interpretation written on the medical record. This applies to patients making both spontaneous return visits and booked return visits to the accident and emergency review clinic.
5. Look at every radiograph, the whole radiograph, and the radiograph as a whole
It is easy to rush and take short cuts in the pressured environment of accident and emergency. But every radiograph must be adequately assessed in a calm manner with a proper viewing box. An additional bright light and reduced ambient light are also essential as they help in interpreting low density areas such as the soft tissues and overexposed parts of films.
A common mistake is to focus immediately on severe abnormalities or on particular areas of the film. This may lead you to fail to inspect the whole film and consequently to miss additional abnormalities. This mistake can be avoided by having a method for inspecting the whole radiograph, and we recommend the ABCs approach (box).3 The system is further modified for regions such as the abdomen and chest, where it is important to stand back and look at the film as a whole.3 Studying radiographs close up, in a well lit, noisy room with many distractions, increases the chances of missing abnormalities.
ABCs method for interpreting radiographs
C—Cartilage and joints
The first step in assessing adequacy is to check the name and date on each film as it is easy for films to be put back into a packet belonging to a different patient. Once the correct radiograph is identified you should check that all of the area of interest can be seen—for example, for views of the cervical spine, the base of the skull, and the upper aspect of T1 must be visible.3 15
Note the alignment of the patient to the radiograph because this affects the appearance of bone and soft tissue. For example, the density of the hilum and the dimensions of the heart can be greatly altered if the patient's chest is rotated when the film is taken. Variations in alignment of joints are also important as they may obscure abnormalities. For example, if the hip joint is externally rotated the position of the greater trochanter can obscure a fracture of the neck of femur.16
Assess the bones by following the cortical lines and noting any breaks, white lines (indicating overriding bones), or steps. The medullary component of the bone should then be checked for abnormalities in the trabecular pattern. Next inspect all the joint spaces and articular surfaces and note abnormal calcification of cartilage and ligaments.
Finally assess the soft tissues as these can indicate an underlying skeletal injury—for example, the prevertebral shadow in the lateral radiograph of the cervical spine3 15 or lipohaemarthrosis of the knee. Lipohaemarthrosis, with the fat-blood interface shown in the horizontal beam lateral radiograph of the knee, indicates an underlying intra-articular fracture that may not itself be visible radiologically.3 17 Once each film has been inspected systematically the different views need to be collated so that the region can be considered as a whole.18
6. Re-examine the patient when there is an incongruity between the radiograph and the expected findings
If the radiograph does not show what the clinical signs have already suggested, check that the correct part and side of the body has been taken. Re-examine the patient to confirm that the site of injury has been identified correctly (fig 2). If such checks confirm that no mistakes have been made special views or investigations may be needed to identify the injury. In elderly patients who have fallen and subsequently cannot walk it is wise to assume that there is a fracture of the neck of femur or pelvis until it is proved otherwise; a bone scan or magnetic resonance imaging may be needed to confirm the diagnosis.
7. The rule of twos
This is an easy discipline to remember and follow.
Two views—Because of its alignment, a fracture may be visible in only one view. Consequently two views at right angles (orthogonal) to each other must be taken. Two views of a radio-opaque foreign body clear from bone are needed to localise it.13
Two joints—Because of the risk of associated dislocation or subluxation when a fracture is suspected, the radiograph must include the joint at either end of the long bones (fig 3).
Two sides—An abnormality can be detected more easily if you compare the normal and injured side, both clinically and radiologically. In children even subtle epiphyseal injuries can be detected in this way. Consequently a child with limited extension of the elbow after injury should have radiographs taken of both elbow joints for comparison at the outset. There are six different epiphyses around the elbow joint which appear between the ages of 6 months and 12 years.
Two occasions—The natural course of certain conditions makes it necessary for radiographs to be repeated at a later date to show the abnormality. Examples include stress and scaphoid fractures where early callus or rarefaction will not be visible for 10-14 days.
Two radiographs—Certain fractures, such as the neck of the talus, are difficult to identify radiologically. However, when the radiograph is compared with a known normal film, the fracture can become much more obvious. It is good practice to have an accessible library of normal radiographs in the accident and emergency department as well as reference books that show normal variants.19 20
8. Take radiographs before and after procedures
Removal of foreign body—As patients have been known to replace foreign bodies in wounds deliberately, it is important that radiographs are taken to confirm that all the pieces have been removed. The patient must be informed, and this documented, if the foreign body cannot be found or its removal is judged not to be in the patient's best interest. However with the eye, if the history suggests an intraocular foreign body the patient must be referred as an emergency immediately even if the radiographs of the orbit appear normal.6
Dislocations—It is essential to confirm that reduction is complete. Joints can redislocate, and the radiograph is the evidence of successful reduction. Associated fractures may be more obvious in films taken after reduction.
Reduction of fractures—It is necessary to confirm that the position of bones is satisfactory because fractures can move after reduction.
9. If a radiograph does not look quite right ask and listen: there is probably something wrong
Inexperienced doctors will inevitably come across injuries that they have never seen before. In these cases it may not be possible to make a diagnosis but you will notice that the films do not look quite right. Good examples of this are lunate and perilunate dislocations of the hand. It is important to seek senior advice and also to listen to the radiographer. Many departments operate a “red dot” system, in which the radiographer flags up an abnormality. An experienced radiographer may be as good as or even better than a junior doctor at interpreting films.
The problem with this system is that the absence of a red dot does not necessary mean that there is no abnormality. This is important to remember because the final responsibility lies with the doctor, and not the radiographer. Therefore never accept poor quality or inadequate films.
10. Ensure you are protected by fail safe mechanisms
All accident and emergency doctors must be specific when they request radiographs, giving the force of injury, the site of injury, and the clinical diagnosis on the request card. Despite improving education, radiological diagnoses will inevitably be missed by all grades of staff.1 6 Consultants must therefore set up systems to minimise the effect of these clinical errors on the patient and in so doing protect staff, the hospital, and themselves (box). To miss an injury radiologically may not be negligent, but it is negligent not to have a system in place to provide for this eventuality. The fail safe mechanisms should be audited regularly. It is much more feasible to run this system effectively if the accident and emergency department has middle grade staff.
The most practical way to instil these 10 commandments into successive teams of senior house officers is with an induction course followed by ongoing teaching using patients in the department—that is, situational teaching.21 The fact that the doctors have faced a diagnostic dilemma, defined the problem, and sought (self directed learning) or asked advice, means that they will retain the knowledge for longer.
Quality control system for interpreting radiographs
On reviewing the films, the doctor records the radiological diagnosis on the request (or return) card
All emergency radiographs must be reviewed by a radiologist, and the report returned, within three working days. Many would now advocate immediate (within 24 hours) reporting as a good standard of practice
The radiologist's report should state clearly whether he or she agrees or disagrees with the radiological diagnosis of the accicent and emergency doctor
All radiographs must be reviewed if the report states disagree. The radiologist must contact the department at once if a serious injury has been missed
The number of complaints from patients is increasing,22 so it is vital that accident departments have adequate staffing levels,23 facilities,24 education,6 and fail safe mechanisms that are audited regularly.25 If these basic prerequisites are not provided hospitals, and perhaps purchasers, make themselves vulnerable.
We thank Mr Sapal Tachakra, director of the Central Middlesex induction course for accident and emergency senior house officers, where this paper is presented biannually. We also thank Dr Teresa Challoner for editorial guidance.
The ABC of Emergency Radiology will be published in April 1995.