title: Effect of permissive hypercapnia on background cerebral electrical activity in premature babies.
abstract: BACKGROUND
  Permissive hypercapnia is routinely practiced in neonatal intensive care units. The effect of permissive hypercapnia on the preterm brain and brain electrical activity is unknown. In this study, we aimed to determine the effect of chronic changes in partial pressure of blood carbon dioxide (PcO2) on brain electrical activity in preterm newborn babies born at or before 32 wk gestation.
  
  
  METHODS
  Eighty-three 1-h long digital electroencephalography (EEG) recordings were performed once a week for 4 wk on 25 babies with median gestational age of 29 wk (range: 23-32) after 48 h of age. Capillary blood gas measurements were performed midway through EEG recordings.
  
  
  RESULTS
  There are associations between EEG parameters and blood pH, PcO2, and blood glucose concentration. However, there are also strong and complex associations with gestational age and substantial individual patient effects that make it difficult to demonstrate predictive associations. PcO2 and bicarbonate are significantly correlated with relative power of θ EEG band and Δ EEG band respectively after adjustment for age and intrababy correlations, but after allowing for multiple testing these relationships are of borderline statistical significance.
  
  
  CONCLUSIONS
  Compensated respiratory acidosis may affect EEG by increased delta wave activity in preterm babies born before 32 wk gestation.
authors.affiliation: 1] Institute of Human Development, University of Manchester, Manchester, UK [2] Central Manchester University Hospitals NHS Foundation Trust, The Manchester Academic Health Sciences Centre, Manchester,UK.
authors.forename: Suresh
authors.initials: S
authors.lastname: Victor
authors.affiliation: School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: McKeering
authors.affiliation: Centre for Biostatistics, Institute of Population Health, University of Manchester, The Manchester Academic Health Sciences Centre, Manchester, UK.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Roberts
authors.affiliation: 1] Centre for Biostatistics, Institute of Population Health, University of Manchester, The Manchester Academic Health Sciences Centre, Manchester, UK [2] Manchester Biomedical Research Centre, Central Manchester University Hospitals NHS Foundation Trust, The Manchester Academic Health Science Centre, Manchester, UK.
authors.forename: Catherine
authors.initials: C
authors.lastname: Fullwood
authors.affiliation: School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK.
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Gaydecki
mesh_terms: D000367:Age Factors; D001639:Bicarbonates / Q000097:blood; D001786:Blood Glucose; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D002245:Carbon Dioxide / Q000097:blood; D004569:Electroencephalography; D005865:Gestational Age; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006935:Hypercapnia / Q000503:physiopathology*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D011446:Prospective Studies
chemical_list: D001639:Bicarbonates; D001786:Blood Glucose; D002245:Carbon Dioxide