Late-Onset Sepsis Evaluation and Empiric Therapy in Extremely Low Gestational Age Newborns.

BACKGROUND: Little is known about late-onset sepsis (LOS) evaluations in extremely low gestational age newborns (ELGANs). We describe frequencies of LOS evaluation in ELGANs, infant characteristics, and empiric therapy choices during evaluations. METHODS: Cohort study of infants 22-28 weeks gestational age (GA) discharged from 243 centers from 2009 to 2018, excluding infants with congenital anomalies, discharged or deceased prior to postnatal day (PND) 2, or admitted after PND 2. A new LOS evaluation was defined as the first blood culture obtained between PND 3 and 90, or one obtained ≥1 day following a negative culture and ≥10 days from prior positive cultures. We determined numbers of evaluations and percentage positive by GA, center, and over time. We described characteristics associated with positive evaluations, infants with LOS, and empiric antimicrobials. We calculated descriptive and comparative statistics using Wilcoxon rank sum, Fisher's exact, or Pearson chi-square tests, as appropriate. RESULTS: Of 47,187 included infants, 67% had ≥1 LOS evaluation and 21% of evaluated infants had ≥1 LOS (culture positive) episode; 1.6 evaluations occurred per infant and 10% were positive. The percentage of infants evaluated and positive for LOS was higher at earlier GA. LOS was associated with inotrope support (15% vs. 9%; p < .001) and invasive mechanical ventilation (66% vs. 51%; p < .001). Infants with positive cultures were more likely than infants with negative cultures to receive empiric antimicrobials during the LOS evaluation (95% vs. 73%; p < .001). CONCLUSIONS: Among ELGANs, earlier GA and postnatal age were associated with LOS evaluation and positive cultures. Most infants undergoing evaluation were started on empiric antimicrobials.