Resuscitation (2007) 72, 100—107 TRAINING AND EDUCATIONAL PAPER CPREzy TM improves performance of external chest compressions in simulated cardiac arrest  Stefan K. Beckers a,b,*,1 , Max H. Skorning a,1 , Michael Fries a , Johannes Bickenbach b , Stephan Beuerlein a , Matthias Derwall a , Ralf Kuhlen b , Rolf Rossaint a a Department of Aneasthesiology, University Hospital Aachen, Rheinisch-Westf¨ alische Technische Hochschule (RWTH) Aachen University, Germany b Department of Intensive Care Medicine, University Hospital Aachen, Rheinisch-Westf¨ alische Technische Hochschule (RWTH) Aachen University, Germany Received 16 May 2006; received in revised form 21 May 2006; accepted 21 May 2006 KEYWORDS Basic life support (BLS); Cardiopulmonary resuscitation (CPR); Cardiac massage; External chest compression (ECC); Training; Layperson Summary Aim of the study: External chest compression (ECC) is an essential part of car- diopulmonary resuscitation and usually performed without any adjuncts. Although different supportive devices have been developed, none have yet been implemented as a standard procedure to guide rescuers in resuscitation. This study investigates the effects of the CPREzy TM -pad on ECC performed by first year medical students during simulated cardiac arrest. Materials and methods: Two hundred and two subjects were randomised and asked to perform 5 min of single-rescuer-CPR. Group 1 (n = 111) was taught classic ECC, followed by ECC with the CPREzy TM and was tested in ECC with the CPREzy TM . Group 2(n =91) was taught and tested in classic ECC only. One week later each group was divided: Group 1A was tested in ECC with the CPREzy TM again; Group 1B was tested in classic ECC. Group 2A was taught and tested in ECC with CPREzy TM ; Group 2B was tested in classic ECC again. Primary endpoints were compression rate (90—110/min) and compression depth (40—50 mm). Results: Comparing groups 1 and 2, ECC was significantly superior with CPREzy TM (correct rate: 93.7% versus 19.8%, p ≤ 0.01; depth: 71.2% versus 34.1%, p ≤ 0.01). The group tested with CPREzy TM initially 1 week later (2A; n = 36) improved significantly in correct compression rate (19.8% versus 88.9%, p ≤ 0.01) and compression depth  A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2006.05.020. * Corresponding author at: Working Group Emergency Medical Care, Department of Anaesthesiology, University Hospital Aachen, Pauwelsstr. 30, D-52074 Aachen, Germany. Tel.: +49 241 80 88179; fax: +49 241 80 82406. E-mail address: sbeckers@ukaachen.de (S.K. Beckers). URL: http://www.anaesthesie.ukaachen.de. 1 These authors contributed equally to the study. 0300-9572/$ — see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2006.05.020