276 - Diagnostic Yield of Chest Radiography Among Febrile Infants Aged 91-365 Days in the Emergency Department

Publication Number: 276.4279

Daniel D. DiLena, Kaiser Permanente Division of Research, San Francisco, CA, United States; Scott D. Casey, kaiser Permanente Vallejo Medical Center, Vallejo, CA, United States; Tara L. Greenhow, kaiser permanente - san francisco medical center, San Francisco, CA, United States; Madeline Somers, Kaiser Permanente Division of Research, Pleasanton, CA, United States; Adina Rauchwerger, Kaiser Permanente, Pleasanton, CA, United States; Tran Nguyen, Kaiser Foundation Hospital - Roseville Women's and Children's Services, Roseville, CA, United States; Mary Reed, Kaiser Permanente Division of Research, Kaiser Permanente Bernard J. Tyson School of Medicine, Pleasanton, CA, United States; David R. Vinson, The Permanente Medical Group, Orangevale, CA, United States; Dustin W. Ballard, Kaiser Permanente/CREST/UC Davis, San Anselmo, CA, United States

Background: Chest radiography (CXR) is often ordered for children with fever and respiratory concerns in the emergency department (ED). Existing clinical guidelines, based on inconclusive results, recommend obtaining chest x-rays in infants with hypoxia, cough, or fever ≥48 hours.

Objective: We sought to assess diagnostic yield of ED CXR in febrile infants, characterize predictors associated with a pneumonia diagnosis by a radiologist, and determine the frequency of inappropriate antibiotics given among pneumonia-negative patients.

Design/Methods: We retrospectively reviewed febrile patients aged 91-365 days who underwent CXR between 01/01/2018 and 12/31/2019 in 21 community EDs. We defined pneumonia as radiographic evidence of focal process/infiltrate, excluding interpretations confined to perihilar infiltrates, bronchiolitis, small airspace disease, or viral process. We extracted data from electronic health records including fever duration, maximum home temperature, respiratory distress, and ill appearance, validated by manual chart review. We used Wilcoxon rank sum and chi-square tests for univariate analysis and modified Poisson regression for multivariate analysis to identify independent predictors of pneumonia-positive CXR. We characterized radiograph findings (normal, indeterminate, or pneumonia) and determined the appropriateness of subsequent antibiotic prescription or administration using manual chart review.

Results: Among 1,472 ED patients who received CXR, average age was 252 days (IQR 188–313 days), 867 (59%) were male, 414 (28%) were white, and 225 patients (15%) had comorbidities. Overall, 212 (14%) were read as pneumonia by a radiologist. Age, sex, and race were not significantly associated with pneumonia-positive results. Among patients with comorbidities, 46 (20%) were positive for pneumonia (p=0.005 compared with patients with none). In multivariate analysis, radiographic evidence of pneumonia was more likely in children with ill appearance (RR 1.92, 95% CI 1.19, 2.99), respiratory distress (RR 2.14, 95% CI 1.59, 2.87), or fever duration ≥72 hours (RR 1.54, 95% CI 1.10, 2.12). Maximum temperature had no significant association with pneumonia-positive CXR. Among 1,260 pneumonia-negative patients, there were 183 (14.5%) antibiotic prescriptions, of which 88 (48%) were determined to be inappropriate.

Conclusion(s): In this ED study, CXR was often a low-value diagnostic and may have contributed to unnecessary antibiotic prescribing in febrile children. Ill appearance, respiratory distress, or fever ≥72 hours may increase diagnostic yield of CXR, supporting existing guidelines.