Organism- and Mortality-Specific Cardiorespiratory Patterns in Late-Onset Neonatal Sepsis: A Four-Neonatal Intensive Care Unit Study of Very Low Birth Weight Infants

Late-onset neonatal sepsis (LOS) in very low birth weight (VLBW) preterm infants varies in severity from mild to fatal and often presents with cardiorespiratory instability. We hypothesized that heart rate (HR) and systemic oxygenation (SpO₂) patterns would differ based on pathogen type and mortality.We analyzed HR and SpO₂ changes before LOS diagnosis for Gram-negative, Coagulase-negative <i>Staphylococcus</i>, and other Gram-positive bacteria (GN, CONS, OGP) and compared survivors and nonsurvivors. Using continuous every-2-second vital sign data from 365 VLBW infants in four neonatal intensive care units, we calculated nine HR and SpO₂ metrics over a 96-hour window.GN LOS was associated with a slightly higher HR, more negative skewness of HR, and higher cross correlation of HR-SpO₂. Mortality was highest in GN LOS (22.7 vs. 4.6% CONS, 8.8% OGP). Nonsurvivors had distinct HR and SpO₂ patterns.These findings highlight critical cardiorespiratory differences at LOS diagnosis associated with mortality risk. · Changes in HR and SpO2 patterns varied by organism type prior to late-onset sepsis in VLBW infants.. · Generally, HR and SpO2 pattern changes showed only small differences based on organism class.. · Patterns associated with fatal sepsis included lower mean SpO2 and lower standard deviation of HR..