Blood pressure, organ dysfunction, and mortality in preterm neonates with late-onset sepsis

Abstract

The objective of this study was to investigate the association between systolic, diastolic, and mean blood pressures (SBP, DBP, and MBP) and adverse outcomes in preterm neonates with late-onset sepsis (LOS). This is a two-center retrospective study over 6 years. Neonates <35 weeks gestational age (GA) with blood ± cerebrospinal fluid culture positive for organisms other than coagulase-negative Staphylococcus at >72 h age were included. Outcome measures were organ dysfunction (ODF) using the predefined criteria and post-ODF mortality (≤7 days from LOS onset). The lowest noninvasive blood pressures (BPs) recorded at baseline (24-48 h pre-LOS) and 0-12, 13-24, 25-36, and 37-48 h post LOS were analyzed. Of 147 neonates, ODF occurred in 70 (48%), of which 20 (29%) died. ODF was associated with a drop in all BP components, starting 0-12 h post-LOS onset (p < 0.01 for all); BPs remained unchanged in the non-ODF group. Mortality was associated with a greater reduction in SBP [-13 (-19, -8) vs. -4 (-8, 0); p < 0.01] and MBP [-9 (-13, -5) vs. +1 (-1, +4); p = 0.03] 0-12 h post-LOS onset. SBP had a higher area under the curve for mortality than MBP and DBP (0.83, 0.81, and 0.78, respectively). An inverse relation may exist between corrected GA and percentage reduction in SBP from baseline for equivalent risk of death. Reduction in BPs early in illness may identify preterm neonates at the highest risk of ODF and mortality from LOS. Drop in BPs from baseline starting in the immediate post-illness onset period may identify preterm neonates at the highest risk of developing ODF and mortality in LOS. Lowest systolic followed by mean BP measured during the first 12 h of illness provided the highest discriminating ability for LOS-related mortality. Absolute BPs recorded during the first 12 h of illness performed better than relative change from baseline for identifying neonates at risk of LOS-related mortality. The specific BP thresholds identified in this study may inform future therapeutic trials.