57 - Rapid Viral Testing and Clinical Outcomes in Febrile Infants 29-90 Days Evaluated in Community Emergency Departments

The indication for lumbar puncture (LP) among infants 29-90 days old continues to evolve.  Rapid viral testing (RVT) for Respiratory Syncytial Virus (RSV) and Influenza are becoming more frequently available in community emergency departments (ED) and having a result that is available during the ED encounter and may inform treatment decisions.

Objective:

The purpose of this study is to describe outcomes in febrile infants 29-90 days comparing those who received RVT to those that received standard viral testing (SVT).

Design/Methods:

We conducted a retrospective observational study of febrile infants (29-90 days old) evaluated in one of 15 emergency departments from January 2010 to December 2019.  We identified the subgroup that had viral testing and compared those with RVT defined as result available before the completion of the ED encounter versus those with SVT defined as result available after the end of the ED encounter. The RVT available during the study period was for Influenza and Respiratory Syncytial Virus (RSV). The primary outcome variable was lumbar puncture obtained.  Multivariate logistic regression was completed with covariates of high-risk white blood cell count, positive leukocyte esterase on urinalysis, age, race, and ethnicity.

Results:

We evaluated 611 febrile infants that presented to one of 15 EDs, 440 (72%) had SVT and 171 (28%) had RVT performed. 261 (42.7%) were admitted to the hospital.  None of the infants died within 30 days of the ED encounter.   

Having received RVT, whether positive or negative, was associated with 56% reduced odds (OR 0.44, 95% CI 0.25-0.74) of lumbar puncture compared to infants who received SVT.  RVT as compared to SVT was also associated with decreased odds of admission (OR 0.17, 95% CI 0.10-0.29) and decreased length of stay for those that were admitted (OR 0.21, 95% CI 0.12 – 0.36). None of the 33 patients with positive RVT had an LP performed.

Conclusion(s):

These results suggest rapid viral testing is associated with significantly reduced odds of having a lumbar puncture performed and being admitted to the hospital in febrile infants 29-90 days old. Confirmation of Influenza or RSV as an explanation for fever in this age group may allow for more focused care and reduction of potentially unnecessary interventions. This, however, does not diminish the significant risk of serious bacterial infections in this age group, thus RVT would act as a supplement to aid in more complex clinical decision making.