title: Near-infrared spectroscopy monitoring of cerebral oxygen during assisted ventilation.
abstract: BACKGROUND
  Changes in the arterial partial pressure of CO(2) (PaCO(2)) has a direct though transient effect on the cerebral vasculature and cerebral circulation. Decreased PaCO(2) levels lead to vasoconstriction and can result in dangerously low levels of cerebral perfusion that resolve in 4-6 h. It is currently believed that perfusion abnormalities contribute to intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL) in the neonate. PaCO(2)-induced vasoconstriction may contribute to the pathology of IVH and PVL.
  
  
  METHODS
  Near-infrared spectroscopy [NIRS; (INVOS cerebral/somatic oximeter; Somanetics Corporation, Troy, MI, USA)] was utilized to determine changes in regional oxygenation (rSO(2)) of the brain in response to changes in ventilation in isoflurane anesthetized newborn piglets.
  
  
  RESULTS
  Changes in cerebral rSO(2) correlated significantly with end-tidal CO(2) levels and to blood flow in the common carotid artery. This correlation was significant during baseline conditions, after periods of CO(2) loading and during periods of hypothermia.
  
  
  CONCLUSIONS
  The results of the study demonstrate the utility of NIRS to accurately reflect changes in cerebral oxygenation and flow to the brain in response to changes in CO(2) levels in anesthetized, ventilated neonatal piglets. The use of NIRS may provide an early alert of low levels of cerebral blood flow and brain oxygenation, potentially helping in preventing the progression of IVH or PVL in the neonate.
authors.affiliation: Department of Medical Science, Somanetics Corporation, Troy, MI, USA.
authors.forename: Erin A
authors.initials: EA
authors.lastname: Booth
authors.forename: Christopher
authors.initials: C
authors.lastname: Dukatz
authors.forename: Beena G
authors.initials: BG
authors.lastname: Sood
authors.forename: Michael
authors.initials: M
authors.lastname: Wider