Variation in ED Use of Computed Tomography for Patients With Minor Head Injury,☆☆,,★★

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Abstract

Study objective: To determine the frequency of utilization, yield for brain injury, incidence of missed injury, and variation in the use of computed tomography (CT) for ED patients with minor head injury. Methods: This retrospective health records survey was conducted over a 12-month period in the EDs at seven Canadian teaching institutions. Included in this review were adult patients who sustained acute minor head injury, defined as witnessed loss of consciousness or amnesia and a Glasgow Coma Scale score of 13 or greater. Data were collected by research assistants who were trained to select cases and abstract data in a standardized fashion according to a resource manual. Subsequently, patient eligibility was reviewed by the study coordinator and principal investigator. Results: Of the 1,699 patients seen, 521 (30.7%) were referred for CT, and 418 (79.8%) of these scans were negative for any type of brain injury. Overall, 105 (6.2%) of these patients sustained acute brain injury, including 9 (.5%) with an epidural hematoma. Cochran's Q test for homogeneity demonstrated significant variation between the seven centers for rate of ordering CT (P<.0001), from a low of 15.9% to a high of 70.4%. All five cases of “missed” hematoma occurred at the institutions with the highest and third highest rates of CT use. After controlling for possible differences in case severity and patient characteristics at each hospital, logistic regression analysis revealed that five of seven hospitals were significantly associated with use of CT (respective odds ratios [OR], .4, .5, .5, 3.2, and 4.7). Three of the centers (two with the highest ordering rates) showed significant heterogeneity in the ordering of CT among their attending staff physicians, from a low of 6.5% to a high of 80.0%. Conclusion: There was considerable variation among institutions and individual physicians in the ordering of CT for patients with minor head injury. Although emergency physicians were selective when ordering CT, the yield of radiography was very low at all hospitals. None of the cases of “missed” intracranial hematoma came from the lowest ordering institutions, indicating that patients may be managed safely with a selective approach to CT use. These findings suggest great potential for more standardized and efficient use of CT of the head, possibly through the use of a clinical decision rule. [Stiell IG, Wells GA, Vandemheen K, Laupacis A, Brison R, Eisenhauer MA, Greenberg GH, MacPhail I, McKnight RD, Reardon M, Verbeek R, Worthington J, Lesiuk H: Variation in ED use of computed tomography for patients with minor head injury. Ann Emerg Med July 1997;30:14-22.]

Section snippets

INTRODUCTION

An estimated 800,000 cases of head injury are seen annually in US EDs.1 Some of these patients die or suffer serious morbidity requiring months of hospitalization and rehabilitation. Many others, however, are classified as having a “minimal” or “minor” head injury. “Minimal” head injury patients have not suffered loss of consciousness or amnesia and rarely require admission to hospital. “Minor” head injury is defined by a history of loss of consciousness or amnesia and Glasgow Coma Scale (GCS)2

MATERIALS AND METHODS

This retrospective health records survey was conducted at seven hospitals in British Columbia and Ontario. These institutions were chosen because they represent typical, busy teaching hospital EDs (35,000 to 65,000 annual visits) in a variety of communities. All departments are staffed by full-time, certified emergency physicians, although many of the patients are seen by residents under the supervision of the emergency physicians. The survey was designed to encompass all eligible adult

RESULTS

During the 12-month review period, 1,699 patients with minor head injury were seen at the seven study hospitals (Table 1). Among all patients, 72% had sustained loss of consciousness, 54% demonstrated amnesia, and most (81%) had a GCS score of 15. Although 72% of all cases arrived at hospital by ambulance, 71% were discharged directly from the ED. Overall, 105 patients (6.2%) had sustained acute brain injury demonstrated on CT although only 9 (.5%) had suffered an epidural hematoma. Demographic

DISCUSSION

This study revealed that although minor head injury is a common ED department problem, the actual prevalence of acute brain injury in this study was low (6.2% of cases) and the prevalence of epidural hematoma was very low (.5%). Although the study physicians were already very selective in ordering CT head scans (30.7% of cases), the yield of CT scans was low, with 79.8% being negative for any acute brain injury. There was a large and significant variation in the ordering rate among the study

Acknowledgements

We thank the following research assistants for their help with the study: Tracy Maciura, Marikay Bailey, Brenda Kearns, Lori Greenberg, Cathy Metcalfe, Patti Barber, Karen Code, Linda O'Brien, Raman Johal, TJ Gill, and Sharon Baker. We also thank Fiona Daigle, My-Linh Tran, and Di Wang for data management; Geri Wells for graphics; Silvia Visentin for assistance with the manuscript; and Dr Annette O'Connor and Dr Graham Nichol for their review of the manuscript.

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  • Cited by (0)

    From the Division of Emergency Medicine,* the Department of Medicine, the Ottawa Civic Hospital Loeb Medical Research Institute,§ and the Division of Neurosurgery, University of Ottawa, Ottawa; the Department of Emergency Medicine, Queens University, Kingston; the Division of Emergency Medicine, University of Western Ontario, London;# and the Division of Emergency Medicine, University of Toronto, Toronto,** Ontario; and the Division of Emergency Medicine, University of British Columbia, Vancouver, British Columbia,‡‡ Canada.

    ☆☆

    Supported by grant GR-13304 from the Medical Research Council of Canada. Drs Stiell and Laupacis are Career Scientists of the Medical Research Council of Canada.

    Reprint no.47/1/82465

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    Address for reprints: Ian G Stiell, MD Clinical Epidemiology Unit Ottawa Civic Hospital Loeb Research Institute 1053 Carling Avenue Ottawa, Ontario Canada K1Y 4E9

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