title: Non-invasive measurement of brain temperature using radiometric thermometry: experimental validation and clinical observations in asphyxiated newborns.
abstract: BACKGROUND
  Therapeutic hypothermia (HT) has been shown to decrease death and severe disability in infants with hypoxic-ischemic encephalopathy (HIE). Rectal temperature (RT) is used to determine the temperature set-points for treatment with HT, however experimental studies have shown significant differences between RT and brain temperature during HT. Knowledge of actual brain temperature during HT might allow better determination of optimal degree of cooling and improve outcomes.
  
  
  OBJECTIVE
  To compare measurements of brain temperature obtained by non-invasive radiometric thermometry (RadT) to direct tissue measurements in an experimental model of HT, and to use RadT in newborn infants with HIE undergoing HT.
  
  
  METHODS
  RadT measurements of brain temperature were compared to fiber optic (Luxtron) thermometry measurements placed at a depth of 1.5 centimeters into the brain of cooled miniswine. Following validation studies, brain RadT and RT measurements were continuously recorded in thirty infants with HIE during HT and rewarming.
  
  
  RESULTS
  RadT and Luxtron probe temperatures were comparable in miniswine throughout a temperature range similar to therapeutic HT. RadT measurements of brain temperature were higher than RT in 60% of infants with HIE undergoing HT. Higher RadT measurements compared to RT were associated with cerebral white matter abnormalities (p = 0.01).
  
  
  CONCLUSIONS
  RadT provides a safe, passive and non-invasive way to measure brain temperature that can be used in the clinical setting. RadT may be helpful in determining the optimal degree of cooling and identifying infants at highest risk of brain injury.
authors.affiliation: Department of Pediatrics, Divisions of Neonatal Medicine, Eastern Virginia Medical School, Children's Hospital of The King's Daughters, Norfolk, VA, USA.
authors.forename: W Thomas
authors.initials: WT
authors.lastname: Bass
authors.affiliation: Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA.
authors.forename: F A
authors.initials: FA
authors.lastname: Lattanzio
authors.affiliation: Department of Pediatrics, Divisions of Neonatal Medicine, Eastern Virginia Medical School, Children's Hospital of The King's Daughters, Norfolk, VA, USA.
authors.forename: G
authors.initials: G
authors.lastname: Brayman
authors.affiliation: Department of Pediatrics, Divisions of Neonatal Medicine, Eastern Virginia Medical School, Children's Hospital of The King's Daughters, Norfolk, VA, USA.
authors.forename: B
authors.initials: B
authors.lastname: Kootsey
authors.affiliation: Developmental Pediatrics, and Eastern Virginia Medical School, Children's Hospital of The King's Daughters, Norfolk, VA, USA.
authors.forename: F
authors.initials: F
authors.lastname: Aiello
authors.affiliation: Biostatistics and Innovation in Research Design, Eastern Virginia Medical School, Children's Hospital of The King's Daughters, Norfolk, VA, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Perkins
authors.affiliation: Meridian Medical Systems, LLC, Portland, Maine, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Carr
authors.affiliation: Meridian Medical Systems, LLC, Portland, Maine, USA.
authors.forename: R C
authors.initials: RC
authors.lastname: Allison
authors.affiliation: Meridian Medical Systems, LLC, Portland, Maine, USA.
authors.forename: J
authors.initials: J
authors.lastname: Shaeffer
authors.affiliation: Meridian Medical Systems, LLC, Portland, Maine, USA.
authors.forename: R
authors.initials: R
authors.lastname: Kelley
mesh_terms: D000818:Animals; D001238:Asphyxia Neonatorum / Q000503:physiopathology*; D001831:Body Temperature / Q000502:physiology*; D004195:Disease Models, Animal; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods; D020925:Hypoxia-Ischemia, Brain / Q000503:physiopathology* / Q000628:therapy; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods; D013552:Swine; D062125:Thermometry / Q000379:methods
keywords: Neonatal hypoxic-ischemic encephalopathy; brain temperature; therapeutic hypothermia