Context

While CT and echocardiography can provide more exact detail of the thoracic organs, the chest x-ray (CXR) is still the first-line investigation for disorders of the heart and lungs in the ED. In the acutely unwell patient, important therapeutic decisions may need to be taken based on its interpretation.

Indications for CXR in emergency medicine

Cardiac

Cardiac indications are:

• Acute coronary syndrome (ACS) – not diagnostic but may show alternative cause for chest pain
• ST segment elevation myocardial infarction (STEMI) – for alternative diagnoses or associated pulmonary oedema. Do not delay revascularisation for CXR
• Heart failure
• Pericarditis and pericardial effusion – normal CXR does not exclude diagnosis
• Suspected pulmonary embolism – normal CXR does not exclude diagnosis

Respiratory

Respiratory indications are:

• Suspected lung cancer or metastases
• Exacerbation of chronic obstructive pulmonary disease (COPD)
• Exacerbation of asthma if localising chest signs, a life-threatening attack or failing to respond to treatment
• Pneumonia
• Pneumothorax
• Pleural effusion
• Haemoptysis

Miscellaneous

Miscellaneous indications include:

• After the insertion of devices – endotracheal tube (ETT), central lines, nasogastric tube
• Suspected inhaled or ingested foreign body (FB)
• Isolated chest wall injury if pneumothorax suspected clinically
• Penetrating chest trauma
• Major trauma
• Acute abdominal pain where perforation is suspected

Learning bite

In cases of chest wall trauma, where an uncomplicated rib fracture is suspected clinically, an x-ray will not change management and is NOT indicated. If, however, a complication – such as pneumothorax or haemothorax – is picked up on clinical examination a confirmatory plain film is required.