title: Early effects of acid-base management during hypothermia on cerebral infarct volume, edema, and cerebral blood flow in acute focal cerebral ischemia in rats.
abstract: BACKGROUND
  Although the frequency for the use of moderate hypothermia in acute ischemic stroke is increasing, the optimal acid-base management during hypothermia remains unclear. This study investigates the effect of pH- and alpha-stat acid-base management on cerebral blood flow (CBF), infarct volume, and cerebral edema in a model of transient focal cerebral ischemia in rats.
  
  
  METHODS
  Twenty Sprague-Dawley rats were subjected to transient middle cerebral artery occlusion (MCAO) for 2 h during normothermic conditions followed by 5 h of reperfusion during hypothermia (33 degrees C). Animals were artificially ventilated with either alpha- (n = 10) or pH-stat management (n = 10). CBF was analyzed 7 h after induction of MCAO by iodo[(14)C]antipyrine autoradiography. Cerebral infarct volume and cerebral edema were measured by high-contrast silver infarct staining (SIS).
  
  
  RESULTS
  Compared with the alpha-stat regimen, pH-stat management reduced cerebral infarct volume (98.3 +/- 33.2 mm(3) vs. 53.6 +/- 21.6 mm(3); P > or = 0.05 mean +/- SD) and cerebral edema (10.6 +/- 4.0% vs. 3.1 +/- 2.4%; P > or = 0.05). Global CBF during pH-stat management exceeded that of alpha-stat animals (69.5 +/- 12.3 ml x 100 g(-1) x min(-1) vs. 54.7 +/- 13.3 ml x 100 g(-1) x min; P > or = 0.05). The regional CBF of the ischemic hemisphere was 62.1 +/- 11.2 ml x 100 g(-1) x min(-1) in the pH-stat group versus 48.2 +/- 7.2 ml x 100 g(-1) x min(-1) in the alpha-stat group ( P> or = 0.05).
  
  
  CONCLUSIONS
  In the very early reperfusion period (5 h), pH-stat management significantly decreases cerebral infarct volume and edema as compared with alpha-stat during moderate hypothermia, probably by increasing CBF.
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology*; D000818:Animals; D000983:Antipyrine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D001345:Autoradiography; D001929:Brain Edema / Q000473:pathology*; D002545:Brain Ischemia / Q000473:pathology* / Q000503:physiopathology*; D002544:Cerebral Infarction / Q000473:pathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D007036:Hypothermia, Induced; D008297:Male; D020768:Middle Cerebral Artery / Q000502:physiology; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D016622:Silver Staining
chemical_list: D019275:Radiopharmaceuticals; D000983:Antipyrine; C008135:iodoantipyrine