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31-10-2011 | Article

CT use rising in the emergency department


Free abstract

MedWire News: Researchers report that there has been a large increase in the use of computed tomography (CT) in US emergency departments (EDs), but the relevance of some procedures is unclear.

The study, by Keith Kocher (University of Michigan, Ann Arbor, USA) and team, covers the 12-year period from 1996 to 2007, and includes data on 368,680 ED patients, obtained from the National Hospital Ambulatory Medical Care Survey.

Overall, 7.5% of patients underwent at least one CT scan while in the ED, but across the study period, CT use increased by 330%, from 3.2% to 13.9%. The rate of ED visits during the study also rose, but only by about 30%, meaning that CT use rose 11 times more than ED visits.

"Given the large number of patients being treated annually in EDs, this finding has enormous implications for the general population," say Kocher et al in the Annals of Emergency Medicine.

They observe that about a quarter of all CT scans undertaken in US hospitals occurred in the ED, but note: "It is possible that many of the CTs previously conducted during a hospitalization are being front loaded into the ED evaluation before admission."

The largest increases in CT use across the study period were for patients with abdominal pain, with rates rising from 1.4% to 31.7% (adjusted 9.97-fold increase), and flank pain, from 3.5% to 43.3% (9.24-fold increase).

There were also increases of about fivefold for patients with chest pain; shortness of breath; neck or back symptoms; and nausea, vomiting, or diarrhea; and of about threefold for those with lower extremity symptoms; convulsions; general weakness; injury; and for cough, upper respiratory, or ears, nose, or throat symptoms.

The researchers say that while the use of CT is essential for some patients, such as those with suspected stroke, its benefits are far less clear for those with complaints such as flank pain.

But they stress: "Our findings are not meant to discount the importance of CT in the ED. CT is an invaluable diagnostic tool for a wide variety of clinical scenarios, and its role in evaluating patients with acute conditions has only increased in recent years."

Indeed, the findings indicate that increased use of CT reduced the rate at which patients were admitted or transferred after the procedure, with the rate falling from 26.0% in 1996 to 12.1% in 2007. However, the effect was only evident until 2003, after which the rate of admission or transfer after CT leveled off.

"Research on understanding how and under what conditions CT is being performed in the ED and developing better strategies for optimizing its use in this setting is needed," the team concludes.

By Eleanor McDermid