Three-part question

[In adults with thoracic trauma] does [emergency department ultrasonography have better clinical utility than chest x ray] at [diagnosing haemothorax]?

Clinical scenario

A patient arrives in the emergency department after suffering thoracic trauma. A member of the team suggests using ultrasound to search for the presence of haemothorax, as an extension of the usual FAST assessment. You wonder how accurate the ultrasound would be compared to either the usual initial supine chest x ray or to a CT scan which could be performed later in the patient’s assessment.

Search strategies

Medline 1966 to present (accessed 29 May 2007) using the OVID interface: [thorax.mp or thoraxic.mp or thoracic.mp or emergancy.mp or chest.mp or pulmonary diseases.mp or thoracic lesions.mp or chest disease.mp]AND [radiography.mp or diagnosis/ or diagnosis, computer assisted/ or diagnosis, differential/ or “diagnostic techniques and procedures”/ or diagnostic imaging/ or radiography or radiography, thoracic/ or tomography, x-ray/ or ultrasonography/ or diagnostic techniques, cardiovascular/ or diagnostic techniques, respiratory system/ or diagnostic tests, routine/ or realy diagnosis or computed tomography.mp or CT.mp or thoracic CT.mp] AND [ultrasound.mp or ultrasonography.mp or explode ultrasonography/ or sonography.mp or radiological diagnosis.mp or ultrasonographic.mp or thoracic radiological procedures.mp or emergency ultrasound.mp or transthoracic ultrasound.mp or thoracic ultrasound.mp] AND [Hemathorax.mp or hemothorax.mp or haemathorax.mp or haemothorax.mp or traumatic effusion.mp].

The Cochrane Library Issue 2 2007: (hemothorax):ti,ab,kw OR (haemothorax):ti,ab,kw

Outcome

Altogether 39 papers were found in Medline, of which 34 were irrelevant or of insufficient quality. Twenty-five papers were found in Cochrane—the only relevant paper had already been found in Medline. A further paper was found by scanning the references of relevant papers. All relevant papers are summarised in table 3.

Comments

Ultrasound is a sensitive, specific and accurate technique for detecting haemothorax in thoracic trauma patients. CT does detect some haemothoraces not seen on ultrasound; however, in a clinical situation, the two methods are performed on different patient populations and so are not directly comparable. The most clinically relevant diagnostic imaging method with which to compare ultrasound is the supine chest radiograph as they both are performed in the initial assessment of the patient. When compared directly to the supine chest x ray, ultrasound is shown to be more specific at detecting the presence of the haemothorax and is at least as specific and accurate. It also has the added advantage of being able to be performed in much less time, making it a useful diagnostic tool for the early diagnosis of haemothorax. However, it cannot replace the chest x ray as many other injuries can be shown on the chest x ray that cannot be demonstrated by ultrasound.

CLINICAL BOTTOM LINE

Ultrasound is a sensitive, specific and accurate method to detect the presence of haemothorax in trauma patients. It cannot, however, replace chest radiography because there is additional information on the x ray that ultrasound cannot provide.