title: Improved cerebral perfusion pressures and 24-hr neurological survival in a porcine model of cardiac arrest with active compression-decompression cardiopulmonary resuscitation and augmentation of negative intrathoracic pressure.
abstract: OBJECTIVE
  Generation of negative intrathoracic pressure during the decompression phase of cardiopulmonary resuscitation enhances the refilling of the heart. We tested the hypothesis that when compared with closed-chest manual compressions at 80 chest compressions per min, treatment with active compression-decompression cardiopulmonary resuscitation at 80 chest compressions/min combined with augmentation of negative intrathoracic pressure would lower intracranial pressure and increase cerebral perfusion, thereby improving neurologically intact survival rates following prolonged untreated cardiac arrest.
  
  
  METHODS
  Prospective, randomized animal study.
  
  
  METHODS
  Animal laboratory facilities.
  
  
  METHODS
  A total of 26 female farm pigs in two different protocols (n = 17 and n = 9).
  
  
  RESULTS
  Seventeen pigs were subjected to 8.5 mins of untreated ventricular fibrillation and prospectively randomized to cardiopulmonary resuscitation at 80 chest compressions/min or active compression-decompression cardiopulmonary resuscitation at 80 chest compressions/min plus an impedance threshold device. Coronary perfusion pressures (29.5 ± 2.7 mm Hg vs. 22.4 ± 1.6 mm Hg, p = .03), carotid blood flow (44.0 ± 12.2 vs. 30.9 ± 10.4, p = .03), and 24-hr neurological survival (88% vs. 22%, p = .015) were higher with active compression-decompression cardiopulmonary resuscitation + an impedance threshold device. Cerebral perfusion pressures, measured in nine additional pigs, were improved with active compression-decompression cardiopulmonary resuscitation + an impedance threshold device (21.9 ± 1.2 mm Hg vs. 8.9 ± 0.8 mm Hg, p < .0001). With active compression-decompression cardiopulmonary resuscitation + impedance threshold device, mean diastolic intracranial pressure during decompression was lower (12.2 ± 0.2 mm Hg vs. 16.6 ± 1.2 mm Hg, p = .02) and the downward slope of the decompression phase intracranial pressure curve was steeper (-60.3 ± 12.9 mm Hg vs. -46.7 ± 11.1 mm Hg/sec, p < .001).
  
  
  CONCLUSIONS
  Active compression-decompression cardiopulmonary resuscitation + an impedance threshold device increased cerebral perfusion pressures and lowered diastolic intracranial pressure and intracranial pressure rate during the decompression phase. These mechanisms may underlie the observed increase in cerebral perfusion pressure, carotid blood flow, and survival rates with favorable neurologic outcomes in this pig model of cardiac arrest.
authors.affiliation: Department of Emergency Medicine, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Anja K
authors.initials: AK
authors.lastname: Metzger
authors.forename: Margot
authors.initials: M
authors.lastname: Herman
authors.forename: Scott
authors.initials: S
authors.lastname: McKnite
authors.forename: Wanchun
authors.initials: W
authors.lastname: Tang
authors.forename: Demetris
authors.initials: D
authors.lastname: Yannopoulos
mesh_terms: D000818:Animals; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D006323:Heart Arrest / Q000503:physiopathology / Q000628:therapy*; D009460:Neurologic Examination; D011897:Random Allocation; D016019:Survival Analysis; D034421:Sus scrofa; D013997:Time Factors; D016896:Treatment Outcome