title: New developments in cerebral blood flow autoregulation analysis in preterm infants: a mechanistic approach.
abstract: BACKGROUND
  Impaired autoregulation capacity implies that changes in cerebral perfusion follow changes in blood pressure; however, no analytical method has explored such a signal causality relationship in infants. We sought to develop a method to assess cerebral autoregulation from a mechanistic point of view and explored the predictive capacity of the method to classify infants at risk for adverse outcomes.
  
  
  METHODS
  The partial directed coherence (PDC) method, which considers synchronicity and directionality of signal dependence across frequencies, was used to analyze the relationship between spontaneous changes in mean arterial pressure (MAP) and the cerebral tissue oxygenation index (TOI). PDCMAP>>TOI indicated that changes in TOI were induced by MAP changes, and PDCTOI>>MAP indicated the opposite.
  
  
  RESULTS
  The PDCMAP>>TOI and PDCTOI>>MAP values differed. PDCMAP>>TOI adjusted by gestational age predicted low superior vena cava flow (≤41 ml/kg per min), with an area under the receiver operating characteristic curve of 0.72 (95% CI: 0.63-0.81; P < 0.001), whereas PDCTOI>>MAP did not. The adjusted pPDCMAP>>TOI (the average value per patient) predicted severe intracranial hemorrhage and mortality.
  
  
  CONCLUSIONS
  PDCMAP>>TOI allows for a noninvasive physiological interpretation of the pressure autoregulation process in neonates. PDCMAP>>TOI is a good classifier for infants at risk of brain hypoperfusion and adverse outcomes.
authors.affiliation: Department of Neonatology, La Paz University Hospital, Madrid, Spain.|Center for Biomedical Technology, Technical University, Madrid, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Riera
authors.affiliation: Biomedical Research Foundation, La Paz University Hospital-IdiPAZ, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Cabañas
authors.affiliation: Center for Biomedical Technology, Technical University, Madrid, Spain.|Biomedical Research Networking Center for Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Zaragoza, Spain.
authors.forename: José Javier
authors.initials: JJ
authors.lastname: Serrano
authors.affiliation: Division of Statistics, La Paz University Hospital, Madrid, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: Madero
authors.affiliation: Department of Neonatology, La Paz University Hospital, Madrid, Spain.
authors.forename: Adelina
authors.initials: A
authors.lastname: Pellicer
mesh_terms: D062186:Arterial Pressure; D001795:Blood Pressure Determination; D001921:Brain / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D015233:Models, Statistical; D010100:Oxygen / Q000097:blood / Q000737:chemistry; D010101:Oxygen Consumption / Q000502:physiology*; D010477:Perfusion; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared; D016896:Treatment Outcome; D014683:Vena Cava, Superior / Q000502:physiology
chemical_list: D010100:Oxygen