title: Even four minutes of poor quality of CPR compromises outcome in a porcine model of prolonged cardiac arrest.
abstract: OBJECTIVE
  Untrained bystanders usually delivered suboptimal chest compression to victims who suffered from cardiac arrest in out-of-hospital settings. We therefore investigated the hemodynamics and resuscitation outcome of initial suboptimal quality of chest compressions compared to the optimal ones in a porcine model of cardiac arrest.
  
  
  METHODS
  Fourteen Yorkshire pigs weighted 30 ± 2 kg were randomized into good and poor cardiopulmonary resuscitation (CPR) groups. Ventricular fibrillation was electrically induced and untreated for 6 mins. In good CPR group, animals received high quality manual chest compressions according to the Guidelines (25% of animal's anterior-posterior thoracic diameter) during first two minutes of CPR compared with poor (70% of the optimal depth) compressions. After that, a 120-J biphasic shock was delivered. If the animal did not acquire return of spontaneous circulation, another 2 mins of CPR and shock followed. Four minutes later, both groups received optimal CPR until total 10 mins of CPR has been finished.
  
  
  RESULTS
  All seven animals in good CPR group were resuscitated compared with only two in poor CPR group (P < 0.05). The delayed optimal compressions which followed 4 mins of suboptimal compressions failed to increase the lower coronary perfusion pressure of five non-survival animals in poor CPR group.
  
  
  CONCLUSIONS
  In a porcine model of prolonged cardiac arrest, even four minutes of initial poor quality of CPR compromises the hemodynamics and survival outcome.
authors.affiliation: Emergency Department, Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University, Guangzhou 510120, China ; Institute of Cardiopulmonary Cerebral Resuscitation, Sun Yat-Sen University, Guangzhou 510120, China ; Department of Emergency Medicine, Taiping People's Hospital, Medical School of Jinan University, Dongguan 523905, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Li
authors.affiliation: Emergency Department, Southwest Hospital of the Third Military Medical University, Chongqing 400038, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Emergency Department, Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University, Guangzhou 510120, China ; Institute of Cardiopulmonary Cerebral Resuscitation, Sun Yat-Sen University, Guangzhou 510120, China.
authors.forename: Zhengfei
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Emergency Department, Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University, Guangzhou 510120, China ; Institute of Cardiopulmonary Cerebral Resuscitation, Sun Yat-Sen University, Guangzhou 510120, China.
authors.forename: Zitong
authors.initials: Z
authors.lastname: Huang
authors.affiliation: School of Biomedical Engineering, Third Military Medical University and Chongqing University, Chongqing 400038, China.
authors.forename: Bihua
authors.initials: B
authors.lastname: Chen
authors.affiliation: Institute of Cardiopulmonary Cerebral Resuscitation, Sun Yat-Sen University, Guangzhou 510120, China ; School of Biomedical Engineering, Third Military Medical University and Chongqing University, Chongqing 400038, China.
authors.forename: Yongqin
authors.initials: Y
authors.lastname: Li
authors.affiliation: Emergency Department, Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University, Guangzhou 510120, China ; Institute of Cardiopulmonary Cerebral Resuscitation, Sun Yat-Sen University, Guangzhou 510120, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
mesh_terms: D000818:Animals; D024201:Bystander Effect; D016887:Cardiopulmonary Resuscitation; D004195:Disease Models, Animal; D006323:Heart Arrest / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D013552:Swine; D014693:Ventricular Fibrillation