Use of emergency department imaging in patients with minor trauma.

BACKGROUND: Advanced radiographic studies have detrimental risks, yet the prevalence of CT utilization in patients with minor trauma presenting to the emergency department (ED) has never been fully evaluated. Our objective was to evaluate the frequency of CT imaging in patients presenting to the ED for minor trauma. MATERIALS AND METHODS: A retrospective analysis of the California Office of Statewide Health Planning and Development Emergency Department and Ambulatory Surgery Data from 2005 to 2013 was performed. A total of 8,535,831 patients were identified using the following inclusion criteria: adult patients (age ≥18 y); with a traumatic ECODE diagnosis and injury severity score <9; and discharge to home. The primary study outcome measurement was the prevalence of CT imaging for each year in the study period. We performed univariate and multivariate analysis to evaluate clinical and hospital-level factors related to CT use in this population. We also performed a trend analysis using Poisson logistic regression to assess the trend of imaging scans over the study period. RESULTS: Of the study population, 5.9% received at least one CT study during their ED visit. The proportion of patients with at least one CT scan increased from 3.51% in 2005 to 7.17% in 2013 (P < 0.005). Adjusted predictors for CT included age 18-24 y or >45 y (P < 0.005), Medicare and self-pay patients (P < 0.005), fall injuries (P < 0.005), motor vehicle collision injuries (P < 0.005), and patients seen at level I/II trauma centers (P = 0.005). CONCLUSIONS: Even after clinical and demographic predictors were adjusted for, there was a 1.97-fold increase in CT among minor trauma patients from 2005-2013.

Risk of contrast-induced nephropathy for patients receiving intravenous vs. intra-arterial iodixanol administration.

PURPOSE: To compare the incidence of contrast-induced nephropathy (CIN) for intravenous vs. intra-arterial administration of iodixanol, compared to non-administration. METHODS: We retrospectively identified 650 patients who had intravenous iodixanol-enhanced CT, 695 with intra-arterial iodixanol cardiac catheterization, 651 with unenhanced CT, and those who also had baseline and follow-up serum creatinine within 5 days of the exam. From the medical records, we recorded the gender, age, baseline and follow-up serum creatinine/eGFR; underlying renal injury risk factors; indication for imaging; contrast material administration volume, concentration, and route of administration; and use of pre-imaging prophylactic measures for CIN. Univariate and multivariate models were used to determine predictors of CIN. RESULTS: Baseline eGFR was lower for patients undergoing unenhanced CT than intravenous or intra-arterial patients (68 vs. 74.6 and 72.2, respectively, p < 0.01) and not different between intravenous and intra-arterial patients (p = 0.735). Simple logistic regression did not show a difference in the rate of CIN in patients who received intravenous vs. intra-arterial iodixanol (28 of 650, 4%, vs. 28 of 695, 4%, respectively, p = 0.798), nor a higher rate of CIN than seen with unenhanced CT (45 of 651, 7%, p = 0.99 and p = 0.98 by one-sided t test). Multivariate regression modeling showed that only elevated baseline creatinine or decreased eGFR and low hematocrit/hemoglobin were associated with CIN incidence (odds ratio 1.28 and 2.5; p < 0.023 and <0.006, respectively). CONCLUSIONS: Elevation in serum creatinine due to intravenous and intra-arterial iodixanol administration is infrequent and is not more common than after unenhanced CT scans.