A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial Infections.

Importance: In young febrile infants, serious bacterial infections (SBIs), including urinary tract infections, bacteremia, and meningitis, may lead to dangerous complications. However, lumbar punctures and hospitalizations involve risks and costs. Clinical prediction rules using biomarkers beyond the white blood cell count (WBC) may accurately identify febrile infants at low risk for SBIs. Objective: To derive and validate a prediction rule to identify febrile infants 60 days and younger at low risk for SBIs. Design, Setting, and Participants: Prospective, observational study between March 2011 and May 2013 at 26 emergency departments. Convenience sample of previously healthy febrile infants 60 days and younger who were evaluated for SBIs. Data were analyzed between April 2014 and April 2018. Exposures: Clinical and laboratory data (blood and urine) including patient demographics, fever height and duration, clinical appearance, WBC, absolute neutrophil count (ANC), serum procalcitonin, and urinalysis. We derived and validated a prediction rule based on these variables using binary recursive partitioning analysis. Main Outcomes and Measures: Serious bacterial infection, defined as urinary tract infection, bacteremia, or bacterial meningitis. Results: We derived the prediction rule on a random sample of 908 infants and validated it on 913 infants (mean age was 36 days, 765 were girls [42%], 781 were white and non-Hispanic [43%], 366 were black [20%], and 535 were Hispanic [29%]). Serious bacterial infections were present in 170 of 1821 infants (9.3%), including 26 (1.4%) with bacteremia, 151 (8.3%) with urinary tract infections, and 10 (0.5%) with bacterial meningitis; 16 (0.9%) had concurrent SBIs. The prediction rule identified infants at low risk of SBI using a negative urinalysis result, an ANC of 4090/µL or less (to convert to ×109 per liter, multiply by 0.001), and serum procalcitonin of 1.71 ng/mL or less. In the validation cohort, the rule sensitivity was 97.7% (95% CI, 91.3-99.6), specificity was 60.0% (95% CI, 56.6-63.3), negative predictive value was 99.6% (95% CI, 98.4-99.9), and negative likelihood ratio was 0.04 (95% CI, 0.01-0.15). One infant with bacteremia and 2 infants with urinary tract infections were misclassified. No patients with bacterial meningitis were missed by the rule. The rule performance was nearly identical when the outcome was restricted to bacteremia and/or bacterial meningitis, missing the same infant with bacteremia. Conclusions and Relevance: We derived and validated an accurate prediction rule to identify febrile infants 60 days and younger at low risk for SBIs using the urinalysis, ANC, and procalcitonin levels. Once further validated on an independent cohort, clinical application of the rule has the potential to decrease unnecessary lumbar punctures, antibiotic administration, and hospitalizations.

Emergency Call Characteristics and EMS Dispatcher Protocol Adherence for Possible Anaphylaxis.

Objective: Anaphylaxis is a medical emergency requiring prompt recognition and treatment with intramuscular epinephrine to optimize outcomes. To date, there is a paucity of data regarding the demographic characteristics of the subset of patients calling 9-1-1 for allergic reactions and the emergency medical services (EMS) dispatcher's adherence to national protocols for their response to a suspected allergic reaction. Methods: We conducted a retrospective review of dispatch calls to a local municipality that were dispatched with an impression of an "allergic reaction" or "difficulty breathing related to a suspected allergic reaction" from January 2016 to June 2016. Using a modified Delphi approach, the voice recordings of the calls were reviewed for EMS dispatcher adherence to the Medical Priority Dispatch System v12.2 (2012) triage questions and pre-arrival instructions for the Allergies/Envenomations and Breathing Problems protocols. The calls were further reviewed for demographic characteristics, symptomatology, history of allergy, suspected trigger of the current reaction, and use and availability of medications. Calls were also classified as to whether the patient met criteria for anaphylaxis. We calculated frequencies for categorical measures and medians with ranges for continuous measures. Results: A total of 146 calls met inclusion criteria. The median age of patients was 29 years (interquartile range 13, 52). 12.3% (n = 18) of the calls reviewed were consistent with national standards for anaphylaxis. Food was the most commonly reported historical allergy, whereas medication accounted for the most commonly suspected trigger for the current symptoms. The EMS dispatcher asked about alertness, difficulty breathing, difficulty speaking, and color change in 39.7, 80.1, 12.3, and 2.7% of calls, respectively. While 56.2% of dispatchers inquired about a history of severe allergy, only 16.4% inquired about prescribed special injections. Conclusions: The majority of calls were not consistent with anaphylaxis, and EMS dispatchers rarely strictly followed the Medical Priority Dispatch System guidelines aimed at identifying anaphylaxis. Future studies would be beneficial to determine if our findings hold true in other EMS service areas.