title: Cerebral physiology and outcome after hypothermic circulatory arrest followed by selective cerebral perfusion.
abstract: BACKGROUND
  This study explored the impact of an interval of hypothermic circulatory arrest (HCA) preceding selective cerebral perfusion (SCP) on cerebral physiology and outcome. This protocol allows use of SCP during aortic surgery without the threat of embolization inherent in balloon catheterization of often severely atherosclerotic cerebral vessels.
  
  
  METHODS
  In this blinded study, 30 pigs (20 to 22 kg) were randomized after cooling to 20 degrees C. Pigs in the HCA-CPB group (n = 10) underwent 30 minutes of HCA followed by 60 minutes of total body perfusion (CPB); HCA-SCP pigs (n = 10) underwent 30 minutes of HCA followed by 60 minutes of SCP, and SCP pigs (n = 10) had 90 minutes of SCP without prior HCA. Fluorescent microspheres enabled calculation of cerebral blood flow during perfusion and recovery. Hemodynamics, intracranial pressure, cerebrovascular resistance, and cerebral oxygen consumption were also monitored. Daily behavioral scores were obtained for 7 days postoperatively.
  
  
  RESULTS
  In all groups, cerebral oxygen consumption fell significantly with cooling (p < 0.0001), remained low during perfusion, and rebounded promptly with rewarming; cerebral oxygen consumption was significantly (p = 0.027) greater during SCP than during HCA-CPB. Cerebral blood flow was significantly higher throughout SCP in the HCA-SCP group (p < 0.0001) than with CPB. Cerebrovascular resistance during SCP and HCA-SCP was significantly lower (p = 0.036) than during CPB. Behavioral scores were significantly better with SCP than with HCA-CPB throughout recovery, but did not differ between SCP and HCA-SCP.
  
  
  CONCLUSIONS
  This study suggests that a short period of HCA preceding SCP provides global cerebral protection comparable to continuous SCP, implying that in clinical practice, a short period of HCA to reduce risk of embolization will not compromise the superior cerebral protection provided by SCP.
authors.affiliation: Mount Sinai School of Medicine, Department of Cardiothoracic Surgery, New York, New York 10029, USA. ju.strauch@gmx.de
authors.forename: Justus T
authors.initials: JT
authors.lastname: Strauch
authors.forename: David
authors.initials: D
authors.lastname: Spielvogel
authors.forename: Peter L
authors.initials: PL
authors.lastname: Haldenwang
authors.forename: Alexander
authors.initials: A
authors.lastname: Lauten
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.forename: Donald
authors.initials: D
authors.lastname: Weisz
authors.forename: Carol A
authors.initials: CA
authors.lastname: Bodian
authors.forename: Randall B
authors.initials: RB
authors.lastname: Griepp
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000502:physiology; D001522:Behavior, Animal; D001783:Blood Flow Velocity; D001921:Brain / Q000378:metabolism*; D002315:Cardiopulmonary Bypass; D002560:Cerebrovascular Circulation; D005260:Female; D006324:Heart Arrest, Induced; D007036:Hypothermia, Induced; D007427:Intracranial Pressure; D019344:Lactic Acid / Q000378:metabolism; D008026:Ligation; D010101:Oxygen Consumption; D013552:Swine; D014655:Vascular Resistance
chemical_list: D019344:Lactic Acid