Adequacy and accuracy of nontrauma center computed tomography: What are we missing?

BACKGROUND: Timely and appropriate use of computed tomography (CT) scans is critical to the evaluation of traumatic injuries. The objective of this study was to assess the adequacy of CT scans performed at nontrauma centers (NTCs) as they pertain to the management of trauma patients. METHODS: Adult patients transferred to our ACS-verified Level I trauma center from any NTC between May and December 2012 were enrolled prospectively. Available CT images from NTCs were reviewed in a blinded fashion by our facility's trauma radiologist; his interpretations were compared with those from the NTC. Interpretations of the trauma centers (TCs) images were compared with the NTC interpretations. Means and proportions were used to summarize the data. RESULTS: A total of 235 consecutive patients with a complete dataset were included, of which, 203 (86.4%) had a CT scan performed at an NTC. Additional imaging was obtained at the TC in 76% of patients with outside CT (154 of 203), with inadequacy of outside CTs for patient workup based on mechanism of injury (76%) and technical inadequacy of outside images (31%) being the main, nonexclusive reasons to repeat imaging. Image interpretation by the trauma radiologist at the TC using NTC images identified missed injuries in 49% of the patients, and 90% of these missed injuries were deemed clinically significant, meaning the injury would have altered patient care had they been identified. When the same body region was imaged at the TC, 54% had missed injuries, of which 76% were deemed significant. CONCLUSION: This study demonstrates inaccuracy in the interpretation of NTC images, which can lead to inappropriate management of trauma patients. Parameters other than imaging need to be used to identify patients requiring a higher level of care. LEVEL OF EVIDENCE: Therapeutic and care management study, level V.

Initial inferior vena cava diameter on computed tomographic scan independently predicts mortality in severely injured trauma patients.

BACKGROUND: In the trauma population, patients with physiologic compromise may present with "normal" vital signs. We hypothesized that the inferior vena cava (IVC) diameter could be used as a surrogate marker for hypovolemic shock and predict mortality in severely injured trauma patients. METHODS: A retrospective cohort study was performed at a Level I trauma center on 161 severely injured adult (aged ≥ 16 years) trauma patients who were transported from the scene and underwent abdominal computed tomography within 1 hour. Exposure of interest was dichotomously defined as having an infrarenal transverse to anteroposterior IVC ratio of ≥ 1.9 (flat IVC) or <1.9 (not exposed) based on the area under the curve analysis. The primary outcome was in-hospital mortality. Covariates included initial heart rate, systolic blood pressure, bicarbonate, base excess, creatinine, hemoglobin, and Injury Severity Score (ISS). Correlation analysis between IVC ratio and other known markers of hypoperfusion was performed. Logistic regression was used to determine the independent effect of the IVC ratio on mortality. RESULTS: Of the 161 patients, 30 had a flat IVC. The IVC ratio had a significant (p < 0.05) inverse correlation with initial bicarbonate, hemoglobin, and base excess and a direct correlation with Cr and ISS. After controlling for age, ISS, and presence of severe head injury, patients who had a flat IVC were 8.1 times (95% confidence interval, 1.5-42.9) more likely to die compared with the nonexposed cohort. Importantly, heart rate and systolic blood pressure had no predictive value in this patient population. CONCLUSION: A flat IVC on initial abdominal computed tomographic scan has a significant correlation with other known markers of shock and is an independent predictor of mortality in severely injured trauma patients. This finding should heighten the awareness of the need for aggressive intervention and potential for physiological decompensation in patients with otherwise "normal" vital signs. LEVEL OF EVIDENCE: Prognostic study, level III.