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1567: UTILITY OF HEART RATE VARIABILITY IN THE TRIAGE OF FEBRILE INFANTS

Introduction/Hypothesis: Heart rate, alone, is known to be a poor predictor for serious infections (SI) in infants. There remains an urgent need for a non-invasive, early tool to guide the triage of febrile young infants in the emergency department (ED). Heart rate variability (HRV) has been developed as a quantitative marker of autonomic activity. It examines beat-to-beat variation in heart rates. Profound changes in the autonomic nervous system occur early during sepsis, both in adults as well as children. Our primary aim is to review if HRV characteristics can successfully discriminate between infants with SIs compared to those without. Methods: This is a prospective observational study conducted in the ED of a large tertiary pediatric hospital. Febrile infants < 3 months old with a temperature > 38.0oC were included and followed for outcomes of SIs, defined as: sepsis, meningitis, osteomyelitis, abscess, urinary tract infection or lobar pneumonia. Five-minute HRV parameters were collected in the ED using a non-invasive single lead electrocardiogram. We compared the HRV characteristics between febrile infants with SIs and those without SIs, using the Wilcoxon rank sum test, taking significance at p < 0.05. Results: We recruited 110 infants, of whom 60 (54.5%) were males and the median age was 14 days (Interquartile Range IQR 4.0 – 39). Sixteen (14.5%) infants had SIs, including meningitis, urinary tract infections and pneumonia. Twenty-four (21.8%) infants who received intravenous antibiotics did not have SIs. HRV characteristics that were found to discriminate between infants with SIs and those without included median SDNN (23.8ms [IQR 14.6 – 34.7] vs 38.6ms [IQR 25.0 – 52.2], p=0.003), RR Triangular Index (6.2 [IQR 3.0 – 9.6] vs 9.8 [IQR 6.3 – 12.0], p=0.005), Poincare plot SD1 (16.9ms [IQR 4.2 – 20.8] vs 20.6 ms [IQR 16.3 – 29.1], p=0.032) and SD2 (29.3ms [IQR 18.2 – 44.6] vs 49.4ms [IQR 31.4 – 66.5], p=0.002). Conclusions: This exciting, feasible and non-invasive measurement of HRV has promising potential for translation into ED triage. Such a tool will direct resources to the febrile infants who are most likely to have SIs and enable them to receive urgent investigations and intravenous antibiotics in the ED.