title: The impact of increased chest compression fraction on return of spontaneous circulation for out-of-hospital cardiac arrest patients not in ventricular fibrillation.
abstract: OBJECTIVE
  Greater chest compression fraction (CCF, or proportion of CPR time spent providing compressions) is associated with better survival for out-of-hospital cardiac arrest (OOHCA) patients in ventricular fibrillation (VF). We evaluated the effect of CCF on return of spontaneous circulation (ROSC) in OOHCA patients with non-VF ECG rhythms in the Resuscitation Outcomes Consortium Epistry.
  
  
  METHODS
  This prospective cohort study included OOHCA patients if: not witnessed by EMS, no automated external defibrillator (AED) shock prior to EMS arrival, received >1 min of CPR with CPR process measures available, and initial non-VF rhythm. We reviewed the first 5 min of electronic CPR records following defibrillator application, measuring the proportion of compressions/min during the resuscitation.
  
  
  RESULTS
  Demographics of 2103 adult patients from 10 U.S. and Canadian centers were: mean age 67.8; male 61.2%; public location 10.6%; bystander witnessed 32.9%; bystander CPR 35.4%; median interval from 911 to defibrillator turned on 8 min:27 s; initial rhythm asystole 64.0%, PEA 28.0%, other non-shockable 8.0%; median compression rate 110/min; median CCF 71%; ROSC 24.2%; survival to hospital discharge 2.0%. The estimated linear effect on adjusted odds ratio with 95% confidence interval (OR; 95%CI) of ROSC for each 10% increase in CCF was (1.05; 0.99, 1.12). Adjusted (OR; 95%CI) of ROSC for each CCF category were: 0-40% (reference group); 41-60% (1.14; 0.72, 1.81); 61-80% (1.42; 0.92, 2.20); and 81-100% (1.48; 0.94, 2.32).
  
  
  CONCLUSIONS
  This is the first study to demonstrate that increased CCF among non-VF OOHCA patients is associated with a trend toward increased likelihood of ROSC.
authors.affiliation: University of Ottawa, Ottawa Hospital Research Institute, Ottawa, ON, Canada. cvaillancourt@ohri.ca
authors.forename: Christian
authors.initials: C
authors.lastname: Vaillancourt
authors.forename: Siobhan
authors.initials: S
authors.lastname: Everson-Stewart
authors.forename: Jim
authors.initials: J
authors.lastname: Christenson
authors.forename: Douglas
authors.initials: D
authors.lastname: Andrusiek
authors.forename: Judy
authors.initials: J
authors.lastname: Powell
authors.forename: Graham
authors.initials: G
authors.lastname: Nichol
authors.forename: Sheldon
authors.initials: S
authors.lastname: Cheskes
authors.forename: Tom P
authors.initials: TP
authors.lastname: Aufderheide
authors.forename: Robert
authors.initials: R
authors.lastname: Berg
authors.forename: Ian G
authors.initials: IG
authors.lastname: Stiell
mesh_terms: D000368:Aged; D001775:Blood Circulation / Q000502:physiology*; D002170:Canada / Q000453:epidemiology; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004632:Emergency Medical Services; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D016017:Odds Ratio; D058687:Out-of-Hospital Cardiac Arrest / Q000209:etiology / Q000401:mortality / Q000628:therapy*; D011446:Prospective Studies; D020127:Recovery of Function; D015996:Survival Rate / Q000639:trends; D013909:Thorax; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D014693:Ventricular Fibrillation / Q000150:complications / Q000503:physiopathology / Q000628:therapy*