title: Cardiac output, coronary blood flow, and blood gases during open-chest standard and compression-active-decompression cardiopulmonary resuscitation.
abstract: OBJECTIVE
  To determine whether open-chest compression-active-decompression (CAD) could improve cardiac output, coronary blood flow, blood gases, and resuscitation compared to open-chest manual compression in a porcine model of cardiac arrest.
  
  
  METHODS
  Prospective, randomized laboratory investigation for measurement of cardiac output, coronary blood flow, arterial and mixed venous blood gases and potassium levels, and return of spontaneous circulation.
  
  
  METHODS
  Ten pigs each weighing approximately 36.4 kg.
  
  
  METHODS
  Following preparation of the model and opening of the chest, ultrasonic flow probes were placed on the ascending aorta and left anterior descending artery. Cardiac arrest was induced by epicardial pacing. Subjects received either open-chest CAD or open-chest manual compression. After 10 min of arrest, defibrillation was attempted.
  
  
  RESULTS
  Cardiac output fell to 46+/-53% (95% CI: -20 to 112) and 41+/-14% (95% CI: 23-59) (P>0.05) of baseline with CAD and manual methods at 5 min after arrest, respectively. Similarly, coronary blood flow fell to 33+/-14% (95% CI: 16-50) and 42+/-16% (95% CI: 22-62) (P>0.05) of baseline at 5 min. Both groups developed similar levels of metabolic acidosis, mixed venous hypoxemia, and hyperkalemia, with potassium levels: 6.5+/-4.0 meq/l (95% CI: 1.6-11.4) at 5 min and 7.5+/-4.6 meq/l (95% CI: 1.8-13.2) at 10 min in the CAD group and 5.8+/-2.0 meq/l (95% CI: 3.4-8.3) at 5 min and 6.1+/-1.4 meq/l (95% CI: 4.4-7.9) at 10 min in the manual group. Levels of hyperkalemia were inversely proportional to the square of PvO(2). One pig in each group was resuscitated after defibrillation.
  
  
  CONCLUSIONS
  We found no benefit using CAD. Both low coronary blood flow and hyperkalemia may have limited resuscitation.
authors.affiliation: Department of Anesthesiology and Internal Medicine, St. Vincent Mercy Medical Center, 2213 Cherry Street, Toledo, OH 43608, USA. engoren@pol.net
authors.forename: Milo
authors.initials: M
authors.lastname: Engoren
authors.forename: Fred
authors.initials: F
authors.lastname: Severyn
authors.forename: Nancy
authors.initials: N
authors.lastname: Fenn-Buderer
authors.forename: Michael
authors.initials: M
authors.lastname: DeFrank
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output / Q000502:physiology*; D016887:Cardiopulmonary Resuscitation / Q000295:instrumentation / Q000379:methods*; D003326:Coronary Circulation / Q000502:physiology*; D004195:Disease Models, Animal; D006323:Heart Arrest / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D000860:Hypoxia / Q000097:blood* / Q000209:etiology; D010100:Oxygen / Q000097:blood*; D011188:Potassium / Q000097:blood*; D011446:Prospective Studies; D011897:Random Allocation; D013552:Swine
chemical_list: D002245:Carbon Dioxide; D011188:Potassium; D010100:Oxygen