Framework for considering abnormal heart rate characteristics and other signs of sepsis in very low birth weight infants
Objective: A heart rate characteristics index (HeRO score), incorporating low variability and superimposed decelerations, was developed as a sepsis risk indicator for preterm infants in the NICU. A rise in the risk score should prompt consideration of other clinical changes that may be signs of sepsis to decide whether a workup and antibiotics are indicated. We aimed to develop a framework to systematically consider signs potentially indicating sepsis in very low birth weight (VLBW) infants. Study Design We developed easy-recall acronyms for ten signs of sepsis in VLBWs. Over 12 months in a level IV NICU, Neonatology Fellows completed a brief survey after each shift to document changes prompting sepsis work-ups. We analyzed associations between survey data, hourly HRC data, and the diagnosis of the work-up, grouped as culture-positive sepsis (CXSEP, positive blood or urine culture), clinical sepsis (CLINSEP, negative cultures treated with antibiotics ≥5 days), or sepsis ruled out (SRO, negative cultures, <3 days antibiotics). Results We analyzed 93 sepsis work-ups in 48 VLBW infants (35 CXSEP, 20 CLINSEP, 38 SRO). The most frequently cited changes prompting the work-ups were heart rate patterns and respiratory deterioration, which were common in all three categories. Low blood pressure and poor perfusion were uncommonly cited but were more likely to be associated with CXSEP than the other signs. A rise in the HeRO score ≥1 from 0-12h before the blood culture compared to 12-72h prior occurred in 31% of work-ups diagnosed as CXSEP, 16% CLINSEP, and 31% SRO. Conclusion The HeRO score can alert clinicians to VLBW infants at high or increasing risk for a sepsis-like illness, but HRC patterns are highly variable in individual babies. The easy-recall NeoSEP-10 framework can assist clinicians in considering other clinical changes when making decisions about sepsis work-ups and the duration of antibiotics.