title: Cold retrograde cerebral perfusion improves cerebral protection during moderate hypothermic circulatory arrest: A long-term study in a porcine model.
abstract: BACKGROUND
  Deep hypothermic circulatory arrest is an effective method of cerebral protection, but it is associated with long cardiopulmonary bypass times and coagulation disturbances. Previous studies have shown that retrograde cerebral perfusion can improve neurologic outcomes after prolonged hypothermic circulatory arrest. We tested the hypothesis that deep hypothermic retrograde cerebral perfusion could improve cerebral outcome during moderate hypothermic circulatory arrest.
  
  
  METHODS
  Twelve pigs (23-29 kg) were randomly assigned to undergo either retrograde cerebral perfusion (15 degrees C) at 25 degrees C or hypothermic circulatory arrest with the head packed in ice at 25 degrees C for 45 minutes. Flow was adjusted to maintain superior vena cava pressure at 20 mm Hg throughout retrograde cerebral perfusion. Hemodynamic, electrophysiologic, metabolic, and temperature monitoring were carried out until 4 hours after the start of rewarming. Daily behavioral assessment was performed until elective death on day 7. A postmortem histologic analysis of the brain was carried out on all animals.
  
  
  RESULTS
  In the retrograde cerebral perfusion group, 5 (83%) of 6 animals survived 7 days compared with 2 (33%) of 6 in the hypothermic circulatory arrest group. Complete behavioral recovery was seen in 4 (67%) animals after retrograde cerebral perfusion but only in 1 (17%) animal after hypothermic circulatory arrest. Postoperative levels of serum lactate were higher, and blood pH was lower in the hypothermic circulatory arrest group. There were no significant hemodynamic differences between the study groups.
  
  
  CONCLUSIONS
  Cold hypothermic retrograde cerebral perfusion during moderate hypothermic circulatory arrest seems to improve neurologic outcome compared with moderate hypothermic circulatory arrest with the head packed in ice.
authors.affiliation: Department of Surgery Oulu University Hospital, Oulu, Finland.
authors.forename: V
authors.initials: V
authors.lastname: Anttila
authors.forename: K
authors.initials: K
authors.lastname: Kiviluoma
authors.forename: M
authors.initials: M
authors.lastname: Pokela
authors.forename: J
authors.initials: J
authors.lastname: Rimpiläinen
authors.forename: M
authors.initials: M
authors.lastname: Mäkiranta
authors.forename: V
authors.initials: V
authors.lastname: Jäntti
authors.forename: J
authors.initials: J
authors.lastname: Hirvonen
authors.forename: T
authors.initials: T
authors.lastname: Juvonen
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003080:Cold Temperature; D004569:Electroencephalography; D005260:Female; D006324:Heart Arrest, Induced; D007036:Hypothermia, Induced; D016343:Monitoring, Intraoperative; D010477:Perfusion / Q000379:methods; D011897:Random Allocation; D015427:Reperfusion Injury / Q000517:prevention & control*; D017694:Rewarming; D013552:Swine