title: Chest compression and ventilation rates during cardiopulmonary resuscitation: the effects of audible tone guidance.
abstract: OBJECTIVE
  To determine: 1) whether chest compressions during CPR are being performed according to American Heart Association (AHA) guidelines during cardiac arrest; and 2) the effect of an audio prompt to guide chest compressions on compliance with AHA guidelines and hemodynamic parameters associated with successful resuscitation.
  
  
  METHODS
  An observational clinical report and laboratory study was conducted. A research observer responded to a convenience sample of cardiac arrests within a 300-bed hospital and counted the rate of chest compressions and ventilations during CPR. To evaluate the effect of an audio prompt on CPR, health care providers performed chest compression without guidance using a porcine cardiac arrest model for 1 minute, followed by a second minute in which audio guidance was added. Chest compression rates, arterial and venous blood pressures, end-tidal CO2 (ETCO2) levels, and coronary perfusion pressures were measured and compared for the two periods.
  
  
  RESULTS
  Twelve in-hospital cardiac arrests were observed in the clinical part of the study. Only two of 12 patients had chest compressions performed within AHA guidelines. No patient had respirations performed within AHA guidelines. In the laboratory, 41 volunteers were tested, with 66% performing chest compressions outside the AHA standards for compression rate without audible tone guidance. With guided chest compressions, the mean (+/- SD) chest compression rate increased from 74 +/- 22 to 100 +/- 3/min (p < 0.01). End-tidal CO2 levels increased from 15 +/- 7 to 17 +/- 7 torr (p < 0.01). Coronary perfusion pressure increased minimally with audible tone-guided chest compressions.
  
  
  CONCLUSIONS
  The majority of Basic Cardiac Life Support--certified health care professionals did not perform CPR according to AHA-recommended guidelines. The use of audible tones to guide chest compression resulted in significantly higher chest compression rates and ETCO2 levels.
authors.affiliation: University Heart Center, University of Arizona Colege of Medicine, Tucson 85724, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Milander
authors.forename: P S
authors.initials: PS
authors.lastname: Hiscok
authors.forename: A B
authors.initials: AB
authors.lastname: Sanders
authors.forename: K B
authors.initials: KB
authors.lastname: Kern
authors.forename: R A
authors.initials: RA
authors.lastname: Berg
authors.forename: G A
authors.initials: GA
authors.lastname: Ewy
mesh_terms: D000572:American Heart Association; D000818:Animals; D016887:Cardiopulmonary Resuscitation / Q000193:education / Q000379:methods* / Q000592:standards; D002983:Clinical Competence / Q000592:standards*; D003463:Cues; D004195:Disease Models, Animal; D006439:Hemodynamics; D006801:Humans; D010564:Personnel, Hospital / Q000193:education / Q000592:standards*; D017410:Practice Guidelines as Topic; D011446:Prospective Studies; D016037:Single-Blind Method; D013552:Swine; D013997:Time Factors; D014160:Transducers, Pressure