title: Regional distribution of blood flow during proximal aortic cross-clamping: an experimental study using coloured microspheres.
abstract: OBJECTIVE
  To investigate the effect of thoracic aortic cross-clamping on blood perfusion of the brain, spinal cord, heart, muscular tissue and visceral organs.
  
  
  METHODS
  Nine pigs underwent 30 min cross-clamping of the descending thoracic aorta. Multiple coloured microspheres (15.0 microm +/- 0.1) were infused into the left ventricle before and during aortic cross-clamping (XC) and after declamping (DC). Tissue samples were analysed by spectrophotometry.
  
  
  RESULTS
  Blood perfusion of the middle and lower segments of the spinal cord was significantly reduced during aortic XC. Perfusion of the brain was not significantly altered by aortic XC, while perfusion of myocardium increased 3-fold. During XC, perfusion of the deltoid muscle and diaphragm increased 5-fold and 13-fold, respectively, while a decrease was found in the gluteus muscle. Renal blood flow was significantly reduced during XC. Finally, XC induced a significant decrease of perfusion in the bowel, spleen, liver and pancreas.
  
  
  CONCLUSIONS
  During XC of the thoracic aorta, the perfusion of the muscular tissue was significantly increased proximal to the level of XC. The circulation of the brain was unchanged, probably because of autoregulatory mechanisms. Blood perfusion of the myocardium increased 3-fold during XC.
authors.affiliation: Department of Surgery, University Hospital of Trondheim, Trondheim, Norway.
authors.forename: O S
authors.initials: OS
authors.lastname: Brattli
authors.forename: K
authors.initials: K
authors.lastname: Nystuen
authors.forename: O D
authors.initials: OD
authors.lastname: Saether
authors.forename: P
authors.initials: P
authors.lastname: Aadahl
authors.forename: J E
authors.initials: JE
authors.lastname: Grønbech
authors.forename: H O
authors.initials: HO
authors.lastname: Myhre
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000503:physiopathology* / Q000601:surgery; D002490:Central Nervous System / Q000098:blood supply*; D003250:Constriction; D003331:Coronary Vessels; D004195:Disease Models, Animal; D005260:Female; D007431:Intraoperative Complications; D008297:Male; D008863:Microspheres; D018482:Muscle, Skeletal / Q000098:blood supply*; D012039:Regional Blood Flow / Q000502:physiology; D013152:Splanchnic Circulation; D013552:Swine / Q000502:physiology*; D014656:Vascular Surgical Procedures / Q000009:adverse effects*