Skip to main navigation menu Skip to main content Skip to site footer

Original article

Vol. 143 No. 3536 (2013)

ABC versus CAB for cardiopulmonary resuscitation: a prospective, randomized simulator-based trial

  • Stephan Marsch
  • Franziska Tschan
  • Norbert K Semmer
  • Roger Zobrist
  • Patrick Hunziker
  • Sabina Hunziker
Cite this as:
Swiss Med Wkly. 2013;143:w13856


QUESTIONS UNDER STUDY: After years of advocating ABC (Airway-Breathing-Circulation), current guidelines of cardiopulmonary resuscitation (CPR) recommend CAB (Circulation-Airway-Breathing). This trial compared ABC with CAB as initial approach to CPR from the arrival of rescuers until the completion of the first resuscitation cycle.

METHODS: 108 teams, consisting of two physicians each, were randomized to receive a graphical display of either the ABC algorithm or the CAB algorithm. Subsequently teams had to treat a simulated cardiac arrest. Data analysis was performed using video recordings obtained during simulations. The primary endpoint was the time to completion of the first resuscitation cycle of 30 compressions and two ventilations.

RESULTS: The time to execution of the first resuscitation measure was 32 ± 12 seconds in ABC teams and 25 ± 10 seconds in CAB teams (P = 0.002). 18/53 ABC teams (34%) and none of the 55 CAB teams (P = 0.006) applied more than the recommended two initial rescue breaths which caused a longer duration of the first cycle of 30 compressions and two ventilations in ABC teams (31 ± 13 vs.23 ± 6 sec; P = 0.001). Overall, the time to completion of the first resuscitation cycle was longer in ABC teams (63 ± 17 vs. 48 ± 10 sec; P <0.0001).

CONCLUSIONS: This randomized controlled trial found CAB superior to ABC with an earlier start of CPR and a shorter time to completion of the first 30:2 resuscitation cycle. These findings endorse the change from ABC to CAB in international resuscitation guidelines.


  1. Cardiopulmonary resuscitation: Statement by the ad hoc committee on cardiopulmonary resuscitation of the division of medical sciences, national academy of sciences-national research council. JAMA. 1966;198:372–9.
  2. Standards for cardiopulmonary resuscitation (CPR) and emergency cardiac care (ECC). JAMA. 1974;227:833–68.
  3. Standards and guidelines for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiac Care (ECC). National Academy of Sciences – National Research Council. JAMA. 1986;255:2905–89.
  4. Standards and guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiac care (ECC). JAMA. 1980;244:453–509.
  5. Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. The American Heart Association in collaboration with the International Liaison Committee on Resuscitation. Resuscitation. 2000;46:1–448.
  6. European Resuscitation Council Guidelines for Resuscitation 2005. Resuscitation. 2005;67S1:S1–S189.
  7. Handley AJ, Koster R, Monsieurs K, Perkins GD, Davies S, Bossaert L. European Resuscitation Council Guidelines for Resuscitation 2005: Section 2. Adult basic life support and use of automated external defibrillators. Resuscitation. 2005; 67(Supplement 1):S7–S23.
  8. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2005;112:IV1–203.
  9. Koster RW, Baubin MA, Bossaert LL, Caballero A, Cassan P, Castr+®n M, et al. European Resuscitation Council Guidelines for Resuscitation 2010 Section 2. Adult basic life support and use of automated external defibrillators. Resuscitation. 2010;81:1277–92.
  10. Berg RA, Hemphill R, Abella BS, Aufderheide TP, Cave DM, Hazinski MF, et al. Part 5: Adult Basic Life Support. Circulation. 2010;122:S685–S705.
  11. Lubrano R, Cecchetti C, Bellelli E, Gentile I, Loayza Levano H, Orsini F, et al. Comparison of times of intervention during pediatric CPR maneuvers using ABC and CAB sequences: A randomized trial. Resuscitation. 2012;83:1473–7.
  12. Marsch SC, Tschan F, Semmer N, Spychiger M, Breuer M, Hunziker PR. Performance of first responders in simulated cardiac arrests. Crit Care Med. 2005;33:963–7.
  13. Hunziker S, Tschan F, Semmer NK, Zobrist R, Spychiger M, Breuer M, et al. Hands-on time during cardiopulmonary resuscitation is affected by the process of teambuilding: a prospective randomised simulator-based trial. BMC Emerg Med. 2009;9:3.
  14. Australian Resuscitation Council NZRC. Basic Life Support: Cardiopulmonary Resuscitation. ARC and NZRC Guideline 2010. Emergency Medicine Australasia. 2011;23:259–60.
  15. Klemmer U. Reanimationsrichtlinien 2010. Schweizerische Arztezeitung 2011;92:62–3.
  16. Kern KB, Hilwig RW, Berg RA, Sanders AB, Ewy GA. Importance of Continuous Chest Compressions During Cardiopulmonary Resuscitation: Improved Outcome During a Simulated Single Lay-Rescuer Scenario. Circulation. 2002;105:645–9.
  17. Assar D, Chamberlain D, Colquhoun M, Donnelly P, Handley AJ, Leaves S, et al. Randomised controlled trials of staged teaching for basic life support: 1. Skill acquisition at bronze stage. Resuscitation. 2000;45:7–15.
  18. Heidenreich JW, Higdon TA, Kern KB, Sanders AB, Berg RA, Niebler R, et al. Single-rescuer cardiopulmonary resuscitation: “two quick breaths” – an oxymoron. Resuscitation. 2004;62:283–9.
  19. Kobayashi M, Fujiwara A, Morita H, Nishimoto Y, Mishima T, Nitta M, et al. A manikin-based observational study on cardiopulmonary resuscitation skills at the Osaka Senri medical rally. Resuscitation. 2008;78:333–9.
  20. Cardiopulmonary resuscitation by bystanders with chest compression only (SOS-KANTO): an observational study. The Lancet. 369:920–6.
  21. Iwami T, Kawamura T, Hiraide A, Berg RA, Hayashi Y, Nishiuchi T, et al. Effectiveness of Bystander-Initiated Cardiac-Only Resuscitation for Patients With Out-of-Hospital Cardiac Arrest. Circulation. 2007;116:2900–7.
  22. Dainty KN, Brooks SC, Morrison LJ. Are the 2010 guidelines on cardiopulmonary resuscitation lost in translation? A call for increased focus on implementation science. Resuscitation 2012.
  23. Osterwalder JJ, Braun D. Strengths and weaknesses of chest compression training: a preliminary retrospective study. Swiss Med Wkly. 2011;141:w13221.
  24. Bogenstatter Y, Tschan F, Semmer NK, Spychiger M, Breuer M, Marsch S. How accurate is information transmitted to medical professionals joining a medical emergency? A simulator study. Hum Factors. 2009;51:115–25.
  25. Driskell JE, Salas E, Johnston J. Does stress lead to a loss of team perspective? Group Dynamics: Theory, Research, and Practice 1999;3:291–302.
  26. Tschan F, Vetterli M, Semmer NK, Hunziker S, Marsch SC. Activities during interruptions in cardiopulmonary resuscitation: a simulator study. Resuscitation. 2011;82:1419–23.
  27. Abella BS, Sandbo N, Vassilatos P, Alvarado JP, O’Hearn N, Wigder HN, et al. Chest compression rates during cardiopulmonary resuscitation are suboptimal: a prospective study during in-hospital cardiac arrest. Circulation. 2005;111:428–34.
  28. Hunziker S, Johansson AC, Tschan F, Semmer NK, Rock L, Howell MD, et al. Teamwork and leadership in cardiopulmonary resuscitation. J Am Coll Cardiol. 2011;57:2381–8.
  29. Hunziker S, Tschan F, Semmer NK, Marsch SC. Importance of leadership in cardiac arrest situations: from simulation to real life and back. Swiss Med Wkly. 2013;143:w13774.
  30. Tschan F, Semmer NK, Gautschi D, Hunziker P, Spychiger M, Marsch SU. Leading to recovery: Group performance and coordinative activities in medical emergency driven groups. Human Performance. 2006;19:277–304.

Most read articles by the same author(s)

1 2 > >>