title: Quality of out-of-hospital cardiopulmonary resuscitation with real time automated feedback: a prospective interventional study.
abstract: OBJECTIVE
  To compare quality of CPR during out-of-hospital cardiac arrest with and without automated feedback.
  
  
  METHODS
  Consecutive adult, out-of-hospital cardiac arrests of all causes were studied. One hundred and seventy-six episodes (March 2002-October 2003) without feedback were compared to 108 episodes (October 2003-September 2004) where automatic feedback on CPR was given. Automated verbal and visual feedback was based on measured quality with a prototype defibrillator. Quality of CPR was the main outcome measure and survival was reported as specified in the protocol.
  
  
  RESULTS
  Average compression depth increased from (mean +/- S.D.) 34 +/- 9 to 38 +/- 6 mm (mean difference (95% CI) 4 (2, 6), P < 0.001), and median percentage of compressions with adequate depth (38-51 mm) increased from 24% to 53% (P < 0.001, Mann-Whitney U-test) with feedback. Mean compression rate decreased from 121 +/- 18 to 109 +/- 12 min(-1) (difference -12 (-16, -9), P = 0.001). There were no changes in the mean number of ventilations per minute; 11 +/- 5 min(-1) versus 11 +/- 4 min(-1) (difference 0 (-1, 1), P = 0.8) or the fraction of time without chest compressions; 0.48 +/- 0.18 versus 0.45 +/- 0.17 (difference -0.03 (-0.08, 0.01), P = 0.08). With intention to treat analysis 7/241 control patients were discharged alive (2.9%) versus 5/117 with feedback (4.3%) (OR 1.5 (95% CI; 0.8, 3), P = 0.2). In a logistic regression analysis of all cases, witnessed arrest (OR 4.2 (95% CI; 1.6, 11), P = 0.004) and average compression depth (per mm increase) (OR 1.05 (95% CI; 1.01, 1.09), P = 0.02) were associated with rate of hospital admission.
  
  
  CONCLUSIONS
  Automatic feedback improved CPR quality in this prospective non-randomised study of out-of-hospital cardiac arrest. Increased compression depth was associated with increased short-term survival.
  
  
  BACKGROUND
  ClinicalTrials.gov (NCT00138996), http://www.clinicaltrials.gov/.
authors.affiliation: Institute for Experimental Medical Research, University of Oslo, N-0407 Oslo, Norway. jo.kramer-johansen@medisin.uio.no
authors.forename: Jo
authors.initials: J
authors.lastname: Kramer-Johansen
authors.forename: Helge
authors.initials: H
authors.lastname: Myklebust
authors.forename: Lars
authors.initials: L
authors.lastname: Wik
authors.forename: Bob
authors.initials: B
authors.lastname: Fellows
authors.forename: Leif
authors.initials: L
authors.lastname: Svensson
authors.forename: Hallstein
authors.initials: H
authors.lastname: Sørebø
authors.forename: Petter Andreas
authors.initials: PA
authors.lastname: Steen
mesh_terms: D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D047548:Defibrillators / Q000592:standards*; D004632:Emergency Medical Services / Q000592:standards*; D004739:England; D005260:Female; D019983:Guideline Adherence; D006323:Heart Arrest / Q000401:mortality / Q000628:therapy*; D006336:Heart Massage / Q000379:methods / Q000592:standards*; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D017410:Practice Guidelines as Topic; D011446:Prospective Studies; D011787:Quality of Health Care / Q000592:standards*; D013548:Sweden; D013997:Time Factors