title: Low-dose ketamine combined with pentobarbital in a miniature porcine model for a cardiopulmonary bypass procedure: a randomized controlled study.
abstract: OBJECTIVE
  Porcine anaesthesia remains a great problem for cardiac surgery research and especially with cardiopulmonary bypass procedures. This study was designed to develop a suitable anaesthesia model in which miniature pigs could be induced smoothly and be maintained stably during and after a cardiopulmonary bypass procedure.
  
  
  METHODS
  Thirty-one miniature pigs were randomly divided into two groups and induced using ketamine and pentobarbital (K-P group, n = 15) or pentobarbital (P group, n = 16) alone, respectively. Animals in group K-P were induced with intramuscular injections of ketamine 5 mg kg and pentobarbital 20 mg kg body weight, and those in group P were induced with pentobarbital 30 mg kg alone. After intubation and intravenous catheterization, group K-P was maintained by continuous infusion of ketamine and pentobarbital, and pentobarbital was withdrawn after cardiopulmonary bypass started. Group P received a continuous infusion of pentobarbital throughout the operation. In addition, both groups were injected hourly with midazolam and pipecuronium bolus to achieve optimal surgical conditions.
  
  
  RESULTS
  All of the group K-P animals survived for 24 h postoperatively. Five of the group P animals died from anaesthesia-related respiratory and cardiac arrest: three after induction and two after extubation. The animals in group K-P had more stable haemodynamics and arterial blood gas indices than animals in group P. Furthermore, the percentage of animals achieving satisfactory anaesthetic effects was significantly higher in group K-P than in group P.
  
  
  CONCLUSIONS
  Combination anaesthesia with low-dose ketamine and pentobarbital demonstrated superior haemodynamic and respiratory indices in comparison with pentobarbital. The combination regimen can achieve both hypnosis and analgesia effects with stable circulatory parameters.
authors.affiliation: Heart Center, First Hospital of Tsinghua University, Beijing, China.
authors.forename: Debin
authors.initials: D
authors.lastname: Liu
authors.forename: Jian
authors.initials: J
authors.lastname: Hu
authors.forename: Mingkui
authors.initials: M
authors.lastname: Zhang
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Shao
authors.forename: Hui
authors.initials: H
authors.lastname: Xue
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Wu
mesh_terms: D000759:Adjuvants, Anesthesia / Q000008:administration & dosage; D019162:Anesthetics, Combined / Q000008:administration & dosage*; D000778:Anesthetics, Dissociative / Q000008:administration & dosage; D000818:Animals; D002315:Cardiopulmonary Bypass / Q000379:methods*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D007273:Injections, Intramuscular; D007649:Ketamine / Q000008:administration & dosage*; D008297:Male; D008874:Midazolam / Q000008:administration & dosage; D010424:Pentobarbital / Q000008:administration & dosage*; D017300:Pipecuronium / Q000008:administration & dosage; D011897:Random Allocation; D012119:Respiration / Q000187:drug effects; D013552:Swine; D013556:Swine, Miniature
chemical_list: D000759:Adjuvants, Anesthesia; D019162:Anesthetics, Combined; D000778:Anesthetics, Dissociative; D017300:Pipecuronium; D007649:Ketamine; D010424:Pentobarbital; D008874:Midazolam