Trauma/original researchClinical Prediction Rules for Identifying Adults at Very Low Risk for Intra-abdominal Injuries After Blunt Trauma
Introduction
Abdominal trauma is a leading cause of morbidity and mortality.1 Identifying patients with intra-abdominal injuries can be difficult because the abdominal examination does not reliably identify all patients with intra-abdominal injuries.2, 3, 4, 5, 6 With improvement in computed tomography (CT) technology, abdominal CT scanning has become the primary method of evaluating hemodynamically stable blunt trauma patients believed to be at risk for intra-abdominal injury at both trauma and nontrauma centers.6, 7, 8, 9, 10, 11, 12, 13 Despite the increase in use of abdominal CT scanning in blunt trauma, the indications for abdominal CT in this setting are not well defined.14 Routine abdominal CT scanning of all blunt trauma patients is expensive and impractical in most busy emergency departments (EDs). Furthermore, there is evidence that overuse of CT scanning exposes patients to unnecessary ionizing radiation, potentially leading to lethal malignancies.15, 16, 17, 18 Thus, appropriate selection of injured patients for abdominal CT scanning would provide more efficient, cost-effective, and safe patient care.
Clinical prediction rules have previously been developed to assist clinicians in determining the need for radiographic evaluation of injured patients after head and cervical spine trauma.19, 20, 21, 22, 23 Previous studies suggest that a clinical prediction rule for abdominal imaging may be feasible because these studies have identified several clinical variables associated with an increased risk of intra-abdominal injury.3, 24, 25 Despite the apparent need for an instrument to assist clinicians with decisionmaking about abdominal CT scanning,14 a clinical prediction rule for identifying adult patients with blunt torso trauma who are at risk for intra-abdominal injury has not yet been developed.
The objective of this study was to derive and validate clinical prediction rules to identify adult patients at very low risk for intra-abdominal injury after blunt torso trauma. We hypothesize that we could derive and validate clinical prediction rules that identify a group of patients at sufficiently low risk for intra-abdominal injury that abdominal CT imaging could be obviated.
Section snippets
Materials and Methods
We conducted a prospective observational cohort study at an urban Level I trauma center. The study was approved by the study site's institutional review board.
We enrolled adult patients, 18 years of age or older, with blunt torso trauma who underwent a definitive diagnostic test to determine the presence or absence of intra-abdominal injury. For study purposes, a definitive diagnostic test was defined as any of the following: abdominal CT scan, diagnostic peritoneal lavage, or
Results
From March 2002 to April 2004, we enrolled 3,435 patients into the derivation phase of the study. Of these 3,435 patients, 311 (9.1%; 95% CI 8.1% to 10.1%) were identified as having an intra-abdominal injury. Of the 311 patients with intra-abdominal injuries, 109 (35.0%; 95% CI 29.7% to 40.6%) underwent an acute intervention (therapeutic laparotomy or angiographic embolization). Interventions included the following (mean intervention/patient=1.6): angiographic embolization 6,
Limitations
We did not evaluate all potentially clinically important variables in this study. For example, we did not assess the utility of liver function tests41 because these are not routinely obtained in the evaluation of adult trauma patients. It is possible that several of the patients with hepatic injuries “missed” by the prediction rules would have been identified by these laboratory tests. We did not enroll all eligible patients. The rate of intra-abdominal injury was similar, but we did not
Discussion
In this study, we derived and validated clinical prediction rules with high sensitivity and negative predictive value for identifying adult patients with and without intra-abdominal injury after blunt torso trauma. The clinical variables in these rules are routinely collected as part of the assessment of patients with blunt torso trauma who present to the ED and are thus readily available when the decision to perform abdominal CT scanning is considered. In addition, these variables have
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2017, International Journal of SurgeryCitation Excerpt :It has also been emphasized that CT scanning should be used selectively to minimize these disadvantages. A few studies have assisted clinicians in determining the need for abdominal CT scanning in blunt trauma patients [20–22]. We hypothesized that a nomogram developed to predict the need for abdominal and pelvic CT (APCT) scanning in patients with blunt trauma after the primary survey would predict positive findings on CT scans.
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Supervising editor: Judd E. Hollander, MD
Author contributions: JFH was responsible for the study concept and supervision, analyzing and interpreting the data, and drafting the article. JFH, WRM, and NK were responsible for the study design. JFH, DHW, and JPM acquired the data. All authors were responsible for critical revision of the article for important intellectual content. JFH and NK provided statistical expertise and obtained funding. JH takes responsibility for the paper as a whole.
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article that might create any potential conflict of interest. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. Funded in part by the Society for Academic Emergency Medicine Research Training Grant.
Publication date: Available online May 19, 2009.