title: The impact of chest compression rates on quality of chest compressions - a manikin study.
abstract: OBJECTIVE
  Chest compressions are often performed at a variable rate during cardiopulmonary resuscitation (CPR). The effect of compression rate on other chest compression quality variables (compression depth, duty-cycle, leaning, performance decay over time) is unknown. This randomised controlled cross-over manikin study examined the effect of different compression rates on the other chest compression quality variables.
  
  
  METHODS
  Twenty healthcare professionals performed 2 min of continuous compressions on an instrumented manikin at rates of 80, 100, 120, 140 and 160 min(-1) in a random order. An electronic metronome was used to guide compression rate. Compression data were analysed by repeated measures ANOVA and are presented as mean (SD). Non-parametric data was analysed by Friedman test.
  
  
  RESULTS
  At faster compression rates there were significant improvements in the number of compressions delivered (160(2) at 80 min(-1) vs. 312(13) compressions at 160 min(-1), P<0.001); and compression duty-cycle (43(6)% at 80 min(-1) vs. 50(7)% at 160 min(-1), P<0.001). This was at the cost of a significant reduction in compression depth (39.5(10)mm at 80 min(-1) vs. 34.5(11)mm at 160 min(-1), P<0.001); and earlier decay in compression quality (median decay point 120 s at 80 min(-1) vs. 40s at 160 min(-1), P<0.001). Additionally not all participants achieved the target rate (100% at 80 min(-1) vs. 70% at 160 min(-1)). Rates above 120 min(-1) had the greatest impact on reducing chest compression quality.
  
  
  CONCLUSIONS
  For Guidelines 2005 trained rescuers, a chest compression rate of 100-120 min(-1) for 2 min is feasible whilst maintaining adequate chest compression quality in terms of depth, duty-cycle, leaning, and decay in compression performance. Further studies are needed to assess the impact of the Guidelines 2010 recommendation for deeper and faster chest compressions.
authors.affiliation: Heart of England NHS Foundation Trust, Birmingham, UK. rf1g10@soton.ac.uk
authors.forename: Richard A
authors.initials: RA
authors.lastname: Field
authors.forename: Jasmeet
authors.initials: J
authors.lastname: Soar
authors.forename: Robin P
authors.initials: RP
authors.lastname: Davies
authors.forename: Naheed
authors.initials: N
authors.lastname: Akhtar
authors.forename: Gavin D
authors.initials: GD
authors.lastname: Perkins
mesh_terms: D000704:Analysis of Variance; D018592:Cross-Over Studies; D006336:Heart Massage / Q000592:standards*; D006801:Humans; D008348:Manikins; D011361:Professional Competence; D018709:Statistics, Nonparametric