title: Effect of real-time feedback during cardiopulmonary resuscitation outside hospital: prospective, cluster-randomised trial.
abstract: OBJECTIVE
  To investigate whether real-time audio and visual feedback during cardiopulmonary resuscitation outside hospital increases the proportion of subjects who achieved prehospital return of spontaneous circulation.
  
  
  METHODS
  A cluster-randomised trial.
  
  
  METHODS
  1586 people having cardiac arrest outside hospital in whom resuscitation was attempted by emergency medical services (771 procedures without feedback, 815 with feedback).
  
  
  METHODS
  Emergency medical services from three sites within the Resuscitation Outcomes Consortium in the United States and Canada.
  
  
  METHODS
  Real-time audio and visual feedback on cardiopulmonary resuscitation (CPR) provided by the monitor-defibrillator.
  
  
  METHODS
  Prehospital return of spontaneous circulation after CPR.
  
  
  RESULTS
  Baseline patient and emergency medical service characteristics did not differ between groups. Emergency medical services muted the audible feedback in 14% of cases during the period with feedback. Compared with CPR clusters lacking feedback, clusters assigned to feedback were associated with increased proportion of time in which chest compressions were provided (64% v 66%, cluster-adjusted difference 1.9 (95% CI 0.4 to 3.4)), increased compression depth (38 v 40 mm, adjusted difference 1.6 (0.5 to 2.7)), and decreased proportion of compressions with incomplete release (15% v 10%, adjusted difference -3.4 (-5.2 to -1.5)). However, frequency of prehospital return of spontaneous circulation did not differ according to feedback status (45% v 44%, adjusted difference 0.1% (-4.4% to 4.6%)), nor did the presence of a pulse at hospital arrival (32% v 32%, adjusted difference -0.8 (-4.9 to 3.4)), survival to discharge (12% v 11%, adjusted difference -1.5 (-3.9 to 0.9)), or awake at hospital discharge (10% v 10%, adjusted difference -0.2 (-2.5 to 2.1)).
  
  
  CONCLUSIONS
  Real-time visual and audible feedback during CPR altered performance to more closely conform with guidelines. However, these changes in CPR performance were not associated with improvements in return of spontaneous circulation or other clinical outcomes. Trial Registration Clinical Trials NCT00539539.
authors.affiliation: Department of Emergency Medicine, University of Pittsburgh, 3600 Forbes Ave, Suite 400A, Pittsburgh, PA 15261, USA. hostlerdp@upmc.edu
authors.forename: David
authors.initials: D
authors.lastname: Hostler
authors.forename: Siobhan
authors.initials: S
authors.lastname: Everson-Stewart
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Rea
authors.forename: Ian G
authors.initials: IG
authors.lastname: Stiell
authors.forename: Clifton W
authors.initials: CW
authors.lastname: Callaway
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kudenchuk
authors.forename: Gena K
authors.initials: GK
authors.lastname: Sears
authors.forename: Scott S
authors.initials: SS
authors.lastname: Emerson
authors.forename: Graham
authors.initials: G
authors.lastname: Nichol
mesh_terms: D000328:Adult; D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000379:methods* / Q000592:standards; D002983:Clinical Competence / Q000592:standards; D016000:Cluster Analysis; D003326:Coronary Circulation / Q000502:physiology; D004632:Emergency Medical Services; D005246:Feedback; D006323:Heart Arrest / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome; D055815:Young Adult