title: Induction of a shorter compression phase is correlated with a deeper chest compression during metronome-guided cardiopulmonary resuscitation: a manikin study.
abstract: OBJECTIVE
  Recent studies have shown that there may be an interaction between duty cycle and other factors related to the quality of chest compression. Duty cycle represents the fraction of compression phase. We aimed to investigate the effect of shorter compression phase on average chest compression depth during metronome-guided cardiopulmonary resuscitation.
  
  
  METHODS
  Senior medical students performed 12 sets of chest compressions following the guiding sounds, with three down-stroke patterns (normal, fast and very fast) and four rates (80, 100, 120 and 140 compressions/min) in random sequence. Repeated-measures analysis of variance was used to compare the average chest compression depth and duty cycle among the trials.
  
  
  RESULTS
  The average chest compression depth increased and the duty cycle decreased in a linear fashion as the down-stroke pattern shifted from normal to very fast (p<0.001 for both). Linear increase of average chest compression depth following the increase of the rate of chest compression was observed only with normal down-stroke pattern (p=0.004).
  
  
  CONCLUSIONS
  Induction of a shorter compression phase is correlated with a deeper chest compression during metronome-guided cardiopulmonary resuscitation.
authors: Department of Emergency Medicine, CHA University School of Medicine, Seongnam-Si, Gyeonggi-Do, Republic of Korea. hendrix74@gmail.com
authors: Tae Nyoung
authors: TN
authors: Chung
authors: Jinkun
authors: J
authors: Bae
authors: Eui Chung
authors: EC
authors: Kim
authors: Yun Kyung
authors: YK
authors: Cho
authors: Je Sung
authors: JS
authors: You
authors: Sung Wook
authors: SW
authors: Choi
authors: Ok Jun
authors: OJ
authors: Kim
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016887:Cardiopulmonary Resuscitation / Q000193:education / Q000379:methods* / Q000592:standards; D018592:Cross-Over Studies; D004632:Emergency Medical Services / Q000379:methods* / Q000592:standards; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D006336:Heart Massage / Q000379:methods*; D006801:Humans; D008297:Male; D008348:Manikins; D016544:Patient Simulation; D011446:Prospective Studies; D013337:Students, Medical / Q000523:psychology; D013997:Time Factors