title: The addition of voice prompts to audiovisual feedback and debriefing does not modify CPR quality or outcomes in out of hospital cardiac arrest--a prospective, randomized trial.
abstract: OBJECTIVE
  Chest compression quality is a determinant of survival from out-of-hospital cardiac arrest (OHCA). ERC 2005 guidelines recommend the use of technical devices to support rescuers giving compressions. This prospective randomized study reviewed influence of different feedback configurations on survival and compression quality.
  
  
  METHODS
  312 patients suffering an OHCA were randomly allocated to two different feedback configurations. In the limited feedback group a metronome and visual feedback was used. In the extended feedback group voice prompts were added. A training program was completed prior to implementation, performance debriefing was conducted throughout the study.
  
  
  RESULTS
  Survival did not differ between the extended and limited feedback groups (47.8% vs 43.9%, p = 0.49). Average compression depth (mean ± SD: 4.74 ± 0.86 cm vs 4.84 ± 0.93 cm, p = 0.31) was similar in both groups. There were no differences in compression rate (103 ± 7 vs 102 ± 5 min(-1), p=0.74) or hands-off fraction (16.16% ± 0.07 to 17.04% ± 0.07, p = 0.38). Bystander CPR, public arrest location, presenting rhythm and chest compression depth were predictors of short term survival (ROSC to ED).
  
  
  CONCLUSIONS
  Even limited CPR-feedback combined with training and ongoing debriefing leads to high chest compression quality. Bystander CPR, location, rhythm and chest compression depth are determinants of survival from out of hospital cardiac arrest. Addition of voice prompts does neither modify CPR quality nor outcome in OHCA. CC depth significantly influences survival and therefore more focus should be put on correct delivery. Further studies are needed to examine the best configuration of feedback to improve CPR quality and survival.
  
  
  BACKGROUND
  ClinicalTrials.gov (NCT00449969), http://www.clinicalTrials.gov.
authors.affiliation: Department of Anaesthesiology and Intensive Care, University Hospital Münster, Germany. bohna@stadt-muenster.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Bohn
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Weber
authors.forename: Sascha
authors.initials: S
authors.lastname: Wecker
authors.forename: Ulf
authors.initials: U
authors.lastname: Harding
authors.forename: Nani
authors.initials: N
authors.lastname: Osada
authors.forename: Hugo
authors.initials: H
authors.lastname: Van Aken
authors.forename: Roman P
authors.initials: RP
authors.lastname: Lukas
mesh_terms: D001296:Audiovisual Aids; D016887:Cardiopulmonary Resuscitation / Q000379:methods / Q000592:standards*; D005246:Feedback; D006801:Humans; D058687:Out-of-Hospital Cardiac Arrest / Q000401:mortality / Q000628:therapy*; D011446:Prospective Studies; D016896:Treatment Outcome; D014831:Voice