title: Subclinical decelerations during developing hypotension in preterm fetal sheep after acute on chronic lipopolysaccharide exposure.
abstract: Subclinical (shallow) heart rate decelerations occur during neonatal sepsis, but there is limited information on their relationship with hypotension or whether they occur before birth. We examined whether subclinical decelerations, a fall in fetal heart rate (FHR) that remained above 100 bpm, were associated with hypotension in preterm fetal sheep exposed to lipopolysaccharide (LPS). Chronically-instrumented fetal sheep at 0.7 gestation received continuous low-dose LPS infusions (n = 15, 100 ng/kg over 24 h, followed by 250 ng/kg/24 h for 96 h) or saline (n = 8). Boluses of 1 μg LPS or saline were given at 48 and 72 h. FHR variability (FHRV) was calculated, and sample asymmetry was used to assess the severity and frequency of decelerations. Low-dose LPS infusion did not affect FHR. After the first LPS bolus, 7 fetuses remained normotensive, while 8 developed hypotension (a fall in mean arterial blood pressure of ≥5 mmHg). Developing hypotension was associated with subclinical decelerations, with a corresponding increase in sample asymmetry and FHRV (p < 0.05). The second LPS bolus was associated with similar but attenuated changes in FHR and blood pressure (p < 0.05). In conclusion, subclinical decelerations are not consistently seen during prenatal exposure to LPS, but may be a useful marker of developing inflammation-related hypotension before birth.
authors.affiliation: The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Lear
authors.affiliation: The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
authors.forename: Joanne O
authors.initials: JO
authors.lastname: Davidson
authors.affiliation: The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
authors.forename: Robert
authors.initials: R
authors.lastname: Galinsky
authors.affiliation: The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Yuill
authors.affiliation: The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
authors.forename: Guido
authors.initials: G
authors.lastname: Wassink
authors.affiliation: The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
authors.forename: Lindsea C
authors.initials: LC
authors.lastname: Booth
authors.affiliation: The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
authors.forename: Paul P
authors.initials: PP
authors.lastname: Drury
authors.affiliation: The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
authors.forename: Laura
authors.initials: L
authors.lastname: Bennet
authors.affiliation: The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.
authors.forename: Alistair J
authors.initials: AJ
authors.lastname: Gunn
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003654:Deceleration; D005260:Female; D005333:Fetus / Q000187:drug effects* / Q000503:physiopathology*; D006340:Heart Rate, Fetal / Q000187:drug effects*; D007022:Hypotension / Q000503:physiopathology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D011247:Pregnancy; D018805:Sepsis / Q000503:physiopathology; D012756:Sheep / Q000502:physiology*
chemical_list: D008070:Lipopolysaccharides