title: Work of CPR during two different compression to ventilation ratios with real-time feedback.
abstract: BACKGROUND
  The 2005 Emergency Cardiac Care guidelines for basic life support (BLS) recommend compression to ventilation ratio of 30:2. The effect of the additional exertion required to deliver more chest compressions may present a considerable physical burden on the provider.
  
  
  OBJECTIVE
  To compare cardiopulmonary resuscitation (CPR) performance and perceived exertion during compression to ventilation ratios of 15:2 and 30:2 with real-time feedback during two-rescuer CPR.
  
  
  METHODS
  Eighteen BLS-certified healthcare providers each performed 5 min of chest compressions on a manikin with compression to ventilation ratios of 15:2 or 30:2 on two separate sessions. Heart rate, capillary lactate, and OMNI rate of perceived exertion (RPE) were recorded before and after each session. Subjects were given continuous, automated, feedback via an accelerometer that measured rate, depth, duration, and release of compressions. Compression measurements and feedback messages were recorded continuously during each 5-min session. Data were analyzed using descriptive statistics and t-test to compare groups. Repeated measures ANOVA were used to compare data over the 5-min epoch.
  
  
  RESULTS
  After performing external chest compressions for 5 min, peak heart rate (102+/-24 vs. 106+/-27), capillary lactate (2.2+/-0.95 vs. 2.2+/-0.96), and OMNI RPE (4.3+/-1.2 vs. 4.6+/-1.1) were higher were higher than baseline, but did not differ between 15:2 and 30:2. Compression rate (102+/-24 vs.106+/-27) and depth (38.8+/-3.6 vs. 38.2+/-2.9) did not differ between 15:2 and 30:2 groups or at any minute. Total chest compressions delivered were higher (p<0.05) in the 30:2 group (457+/-43) compared to 15:2 (379+/-28). The average no flow time was lower (p<0.05) in the 30:2 group (22+/-3.03) compared to the 15:2 group (33+/-2.64). Number of correction prompts (48+/-55 vs. 64+/-70) did not differ significantly between the 15:2 and 30:2 groups.
  
  
  CONCLUSIONS
  In a cohort of healthcare providers, increasing the CPR ratio from 15:2 to 30:2 did not change physical or perceived exertion during a 5-min bout of CPR when continuous, real-time feedback is provided. The 30:2 compression to ventilation ratio resulted in more chest compressions per minute without decreasing CPR quality.
authors.affiliation: Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA 15213, United States.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Betz
authors.forename: Clifton W
authors.initials: CW
authors.lastname: Callaway
authors.forename: David
authors.initials: D
authors.lastname: Hostler
authors.forename: Jon C
authors.initials: JC
authors.lastname: Rittenberger
mesh_terms: D000328:Adult; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D018592:Cross-Over Studies; D004734:Energy Metabolism / Q000502:physiology; D030141:Feedback, Psychological; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008348:Manikins; D008954:Models, Biological; D005082:Physical Exertion / Q000502:physiology*; D011446:Prospective Studies; D013813:Therapy, Computer-Assisted; D055815:Young Adult
chemical_list: D019344:Lactic Acid