title: Determinants of mortality after hypothermic circulatory arrest in a chronic porcine model.
abstract: OBJECTIVE
  Beside neurological morbidity, mortality is a relevant end-point of experimental porcine model of hypothermic circulatory arrest (HCA) and this study was conducted to identify the determinants for postoperative death.
  
  
  METHODS
  One hundred and thirty-five pigs underwent a 75-min period of HCA at 20 degrees C to evaluate the efficacy of different methods of cerebral protection.
  
  
  RESULTS
  Survival rate at 7-day follow-up was 52%. Lower oxygen extraction, oxygen consumption/kg, and venous lactate at the end of cooling and higher oxygen delivery rates were significantly associated with better outcome. Logistic regression showed that the oxygen consumption/kg at the end of cooling was the only predictor of mortality (P=0.046). Animals with an oxygen consumption/kg rate less than 1.43 ml/min per kg at the end of cooling had a mortality rate of 28%, whereas it was 50% among animals with an oxygen consumption/kg rate higher or equal to 1.43 ml/min per kg (P=0.020). The latter had even an increased 1-day mortality rate (40% vs. 26%) (P not significant). The mortality rate after anesthesia induction with ketamine plus 100% of oxygen was 38%, 45% after anesthesia induction with ketamine plus 35% oxygen, and 53% after anesthesia with medetomidine plus 35% oxygen (P not significant).
  
  
  CONCLUSIONS
  Parameters of oxyhemodynamics should be monitored especially from the induction of anesthesia to the end of cooling before a 75-min period of HCA. The use of medetomidine and/or 35% of oxygen at induction of anesthesia should be avoided in favor of ketamine plus 100% of oxygen.
authors.affiliation: Department of Cardio-thoracic and Vascular Surgery, Oulu University Hospital, University of Oulu, 90221 Oulu, Finland. tatu.juvonen@oulu.fi
authors.forename: T
authors.initials: T
authors.lastname: Juvonen
authors.forename: F
authors.initials: F
authors.lastname: Biancari
authors.forename: J
authors.initials: J
authors.lastname: Rimpiläinen
authors.forename: V
authors.initials: V
authors.lastname: Anttila
authors.forename: M
authors.initials: M
authors.lastname: Pokela
authors.forename: V
authors.initials: V
authors.lastname: Vainionpää
authors.forename: P
authors.initials: P
authors.lastname: Romsi
authors.forename: K
authors.initials: K
authors.lastname: Kiviluoma
mesh_terms: D000768:Anesthesia, General; D000818:Animals; D002423:Cause of Death; D004195:Disease Models, Animal; D005260:Female; D006324:Heart Arrest, Induced / Q000401:mortality*; D006439:Hemodynamics / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D016019:Survival Analysis; D013552:Swine