title: Effect of arrest time on the hemodynamic efficacy of precordial compression.
abstract: OBJECTIVE
  To evaluate the efficacy of conventional threshold levels of coronary perfusion pressure and end-tidal CO2 as predictors of resuscitability after prolonged cardiac arrest.
  
  
  METHODS
  Prospective, randomized, controlled animal study.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  Twenty-one Sprague-Dawley rats, including three groups of seven animals in each group.
  
  
  METHODS
  Ventricular fibrillation was untreated for 9, 12, or 15 mins. After an additional 5-min interval of precordial compression, external direct current defibrillation was attempted.
  
  
  RESULTS
  All animals were successfully resuscitated after 9 mins of ventricular fibrillation but less than one half of the animals were successfully resuscitated after 15 mins of ventricular fibrillation. Each of seven animals survived for 24 hrs after 9 mins of untreated ventricular fibrillation but none of the animals survived after 15 mins of ventricular fibrillation. In this experimental setting, neither coronary perfusion pressure nor end-tidal CO2 produced by precordial compression was predictive of outcomes when the animals underwent progressively longer intervals of untreated cardiac arrest.
  
  
  CONCLUSIONS
  The efficacy of precordial compression--as measured by coronary perfusion pressure and end-tidal CO2 concentration after prolongation of untreated cardiac arrest--was not overtly compromised. However, the previously established critical threshold levels of coronary perfusion pressure and end-tidal CO2 failed as predictors of resuscitability after prolonged intervals of untreated cardiac arrest.
authors.affiliation: Institute of Critical Care Medicine, University of Health Sciences/The Chicago Medical School, IL, USA.
authors.forename: C
authors.initials: C
authors.lastname: Duggal
authors.forename: M H
authors.initials: MH
authors.lastname: Weil
authors.forename: W
authors.initials: W
authors.lastname: Tang
authors.forename: R J
authors.initials: RJ
authors.lastname: Gazmuri
authors.forename: S
authors.initials: S
authors.lastname: Sun
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006323:Heart Arrest / Q000209:etiology / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006439:Hemodynamics; D008297:Male; D011446:Prospective Studies; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012151:Resuscitation / Q000379:methods* / Q000706:statistics & numerical data; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000209:etiology / Q000401:mortality / Q000503:physiopathology / Q000628:therapy