title: Elevated cerebral pressure passivity is associated with prematurity-related intracranial hemorrhage.
abstract: OBJECTIVE
  Cerebral pressure passivity is common in sick premature infants and may predispose to germinal matrix/intraventricular hemorrhage (GM/IVH), a lesion with potentially serious consequences. We studied the association between the magnitude of cerebral pressure passivity and GM/IVH.
  
  
  METHODS
  We enrolled infants <32 weeks' gestational age with indwelling mean arterial pressure (MAP) monitoring and excluded infants with known congenital syndromes or antenatal brain injury. We recorded continuous MAP and cerebral near-infrared spectroscopy hemoglobin difference (HbD) signals at 2 Hz for up to 12 hours/day and up to 5 days. Coherence and transfer function analysis between MAP and HbD signals was performed in 3 frequency bands (0.05-0.25, 0.25-0.5, and 0.5-1.0 Hz). Using MAP-HbD gain and clinical variables (including chorioamnionitis, Apgar scores, gestational age, birth weight, neonatal sepsis, and Score for Neonatal Acute Physiology II), we built a logistic regression model that best predicts cranial ultrasound abnormalities.
  
  
  RESULTS
  In 88 infants (median gestational age: 26 weeks [range 23-30 weeks]), early cranial ultrasound showed GM/IVH in 31 (37%) and parenchymal echodensities in 10 (12%) infants; late cranial ultrasound showed parenchymal abnormalities in 19 (30%) infants. Low-frequency MAP-HbD gain (highest quartile mean) was significantly associated with early GM/IVH but not other ultrasound findings. The most parsimonious model associated with early GM/IVH included only gestational age and MAP-HbD gain.
  
  
  CONCLUSIONS
  This novel cerebrovascular monitoring technique allows quantification of cerebral pressure passivity as MAP-HbD gain in premature infants. High MAP-HbD gain is significantly associated with GM/IVH. Precise temporal and causal relationship between MAP-HbD gain and GM/IVH awaits further study.
authors: Fetal-Neonatal Neurology Research Group, Department of Neurology, and Children's Hospital Boston, Massachusetts 02115, USA.
authors: Heather
authors: H
authors: O'Leary
authors: Matthew C
authors: MC
authors: Gregas
authors: Catherine
authors: C
authors: Limperopoulos
authors: Irina
authors: I
authors: Zaretskaya
authors: Haim
authors: H
authors: Bassan
authors: Janet S
authors: JS
authors: Soul
authors: Donald N
authors: DN
authors: Di Salvo
authors: Adré J
authors: AJ
authors: du Plessis
mesh_terms: D001794:Blood Pressure / Q000502:physiology; D004453:Echoencephalography; D005260:Female; D005865:Gestational Age; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D007235:Infant, Premature, Diseases / Q000453:epidemiology / Q000503:physiopathology*; D019102:Infant, Very Low Birth Weight; D020300:Intracranial Hemorrhages / Q000453:epidemiology / Q000503:physiopathology*; D019586:Intracranial Hypertension / Q000453:epidemiology* / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D015995:Prevalence; D019265:Spectroscopy, Near-Infrared