title: Brain oxygenation and metabolism during selective cerebral perfusion in neonates.
abstract: OBJECTIVE
  To investigate the possible neuroprotective effects of selective cerebral perfusion (SCP) during deep hypothermic circulatory arrest on brain oxygenation and metabolism in newborn piglets.
  
  
  METHODS
  Newborn piglets 2-4 days of age, anesthetized and mechanically ventilated, were used for the study. The animals were placed on cardiopulmonary bypass, cooled to 18 degrees C and put on SCP (20 ml/(kg min)) for 90 min. After rewarming, the animals were monitored through 2h of recovery. Oxygen pressure in the microvasculature of the cortex was measured by oxygen-dependent quenching of phosphorescence. The extracellular level of dopamine in striatum was measured by microdialysis and hydroxyl radicals by ortho-tyrosine levels. Levels of phosphorylated cAMP response element binding protein (pCREB) in striatal tissue were measured by Western blots using antibodies specific for phosphorylated CREB. The results are presented as mean+/-SD (p<0.05 was significant).
  
  
  RESULTS
  Pre-bypass cortical oxygen pressure was 48.9+/-11.3 mmHg and during the first 5 min of SCP, the peak of the histogram, corrected to 18 degrees C, decreased to 11.2+/-3.8 mmHg (p<0.001) and stayed near that value to the end of bypass. The mean value for the peak of the histograms measured at the end of SCP was 8+/-3 mmHg (p<0.001). SCP completely prevented the deep hypothermic circulatory arrest-dependent increase in extracellular dopamine and hydroxyl radicals. After SCP, there was a statistically significant increase in pCREB immunoreactivity (534+/-60%) compared to the sham-operated group (100+/-63%, p<0.005). Measurements of total CREB showed that SCP did induce a statistically significant increase in CREB as compared to sham-operated animals (168+/-31%, p<0.05).
  
  
  CONCLUSIONS
  SCP, as compared to DHCA, improved cortical oxygenation and prevented increases in the extracellular dopamine and hydroxyl radicals. The increase in pCREB in the striatum following SCP may contribute to improved cellular recovery after this procedure.
authors.affiliation: Department of Anesthesiology and Critical Care, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Schears
authors.forename: Tatiana
authors.initials: T
authors.lastname: Zaitseva
authors.forename: Steven
authors.initials: S
authors.lastname: Schultz
authors.forename: William
authors.initials: W
authors.lastname: Greeley
authors.forename: Diego
authors.initials: D
authors.lastname: Antoni
authors.forename: David F
authors.initials: DF
authors.lastname: Wilson
authors.forename: Anna
authors.initials: A
authors.lastname: Pastuszko
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000098:blood supply / Q000378:metabolism*; D002315:Cardiopulmonary Bypass; D002560:Cerebrovascular Circulation; D003342:Corpus Striatum / Q000737:chemistry / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000032:analysis / Q000378:metabolism; D004298:Dopamine / Q000032:analysis / Q000378:metabolism; D045604:Extracellular Fluid / Q000737:chemistry / Q000378:metabolism; D005609:Free Radicals / Q000032:analysis / Q000378:metabolism; D007036:Hypothermia, Induced; D008833:Microcirculation; D023421:Models, Animal; D010100:Oxygen / Q000097:blood*; D010477:Perfusion; D013552:Swine
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D005609:Free Radicals; D010100:Oxygen; D004298:Dopamine