Investigators from the State University of New York Downstate Medical Center, Brooklyn, NY, conducted a retrospective study to evaluate the utility of a combination of the Rochester Criteria (RC), Yale Observation Scale (YOS), and an age cut-off to identify a group of febrile infants ≤28 days old at low risk for invasive bacterial infection (IBI), including bacteremia and meningitis. For the study, they reviewed data collected by the Pediatric Emergency Care Applied Research Network (PECARN) on febrile infants <60 days old seen at 26 EDs. For the current analysis, only patients ≤28 days old with temperatures ≥38.0°C who underwent evaluation for IBI were included. The primary study outcomes were bacteremia and bacterial meningitis, both defined by positive culture. The RC and YOS were retrospectively derived from the available data to categorize patients at low risk or higher risk of IBI, using the thresholds recommended by the developers of these instruments. A receiver operator characteristic curve (ROC) analysis was used to identify a cutoff age to classify infants at lower risk for IBI.
A stepwise process was used to ultimately classify febrile infants as low risk. First, the RC were assessed. The YOS then was applied to patients classified as low risk by the RC. Finally, the age cutoff determined by the ROC analysis was used to further categorize infants who had both a reassuring RC and YOS to identify a group of patients at low risk for IBI. The sensitivity and specificity of the 3-step process for identifying febrile infants with IBI were calculated.
Data were analyzed on 1,524 febrile infants with a median age of 19 days. Every patient had a blood culture, and 44 (2.9%) had bacteremia. Cerebrospinal fluid was obtained on 1,428 children, and 21 (1.5%) had meningitis. Ten patients had concomitant bacteremia and meningitis, yielding an overall rate of IBI of 3.6% (55/1,524). Of the 55 patients with IBI, 36 were correctly identified by not meeting the low-risk RC, including 7 with meningitis, 22 with bacteremia, and 7 with both. Among the remaining 19 infants, 4 had a YOS placing them at higher risk for IBI (2 with bacteremia and 2 with both bacteremia and meningitis). Using the ROC analysis, infants >18 days old were categorized at lower risk for IBI. For the remaining 15 patients with IBI, not identified using the RC or YOS, 8 were identified using the age cutoff. The remaining 7 infants with IBI included 1 with meningitis and 6 with bacteremia. The sensitivity and specificity of the 3-step process for identifying febrile infants with IBI were 87% and 30%, respectively.
The authors conclude that by using the RC, YOS, and an age cutoff of 18 days, 30% of febrile infants <28 days...