Panel:Research in contex Systematic review areitore ve dispatcher-assis 2 Push,blo Interpretation .Perkins GD.DaviesS. abtaa2005om2Adhbasice7atnduco out-of-hospital cardiac arrest compared with standard CPR pl非s7-2 5 :116:252 6 00z45 oh- cohor study suggest tha :TK o07:ic908cA.etlEfct compared with chest-compression- 20011 PR ng MEH,Ng FS Anushia P.et al Compa on of chest pre sion-only SadedRaemobe1hrgestinadipicaswt 1 SOS-KANTO由io medical RW hospital cardiac whether L.loh E.Co ale Gv the and nical,or 1 TD,Fahr n M.ct al. 63:34 UsNaiod 18 alth and AMA20a2832008E 19 001423- 200) 21 Gold LS.E m Vol 376 Novembet 6.2010 Articles 1556 www.thelancet.com Vol 376 November 6, 2010 suggest that dispatcher-assisted chest-compression￾only CPR increases survival compared with standard CPR in adults with out-of-hospital cardiac arrest, several circumstances exist in which this CPR technique might not be benefi cial. Findings from a large-scale prospective cohort study suggest that standard CPR might actually improve survival compared with chest-compression-only CPR in cardiac arrest from non-cardiac causes (eg, drowning, trauma, or asphyxia).25 Moreover, in children with out-of￾hospital cardiac arrest, which is often of non-cardiac origin, standard CPR might confer a similar benefi t.26 Therefore, the benefi ts of chest-compression-only bystander CPR seem to be largest in adult patients with sudden cardiac death. Our fi ndings support the idea that emergency medical services dispatch should instruct bystanders to focus on chest-compression-only CPR in adults with out-of￾hospital cardiac arrest. However, whether chest￾compression-only CPR should be recommended for unassisted lay bystander CPR is unclear. Contributors MH and PN were responsible for the study concept and design, and provided administrative, technical, or material support. PN was responsible for obtaining of funding, supervision of the study, acquisition of data, and statistical analysis. All authors contributed to analysis and interpretation of data. MH and PN drafted the report, and all authors contributed to revision of the report. Confl icts of interest PN's institution has received research support from Roche Diagnostics, unrelated to this study; PN has received consultancy fees from Gerson Lehrman Group; and PN and his institution have received grants from the US National Institutes of Health and American Heart Association. MH is receiving a salary and has received payment for development of educational presentations from St John’s Ambulance Service, Vienna, Austria; and has received research support, lecture fees, and travel support from Novo Nordisk. HFS declares that he has no confl icts of interest. Acknowledgments We thank J Philipp Miller, director division of Biostatistics, Washington University School of Medicine, St Louis, MO, USA, for his statistical contributions during report preparation and revision. PN is supported by grants from the National Institute of General Medical Sciences, National Institutes of Health, and from the American Heart Association. References 1 Koster RW. Mouth-to-mouth ventilation and/or chest compression in basic life support: The debate continues. Resuscitation 2008; 77: 283–85. 2 Nolan J. Push, blow or both: is there a role for compression-only CPR? Anaesthesia 2010; 65: 771–74. 3 EEC Committee, Subcommittees and Task Forces of the American Heart Association. 2005 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation 2005; 112: IV1–203. 4 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 defi brillators. Resuscitation 2005; 67 (suppl 1): S7–23. 5 Ewy GA, Zuercher M, Hilwig RW, et al. Improved neurological outcome with continuous chest compressions compared with 30:2 compressions-to-ventilations cardiopulmonary resuscitation in a realistic swine model of out-of-hospital cardiac arrest. Circulation 2007; 116: 2525–30. 6 Sanders AB, Kern KB, Berg RA, Hilwig RW, Heidenrich J, Ewy GA. Survival and neurologic outcome after cardiopulmonary resuscitation with four diff erent chest compression-ventilation ratios. Ann Emerg Med 2002; 40: 553–62. 7 Bohm K, Rosenqvist M, Herlitz J, Hollenberg J, Svensson L. Survival is similar after standard treatment and chest compression only in out-of-hospital bystander cardiopulmonary resuscitation. Circulation 2007; 116: 2908–12. 8 Iwami T, Kawamura T, Hiraide A, et al. Eff ectiveness of bystander￾initiated cardiac-only resuscitation for patients with out-of-hospital cardiac arrest. Circulation 2007; 116: 2900–07. 9 Olasveengen TM, Wik L, Steen PA. Standard basic life support vs. continuous chest compressions only in out-of-hospital cardiac arrest. Acta Anaesthesiol Scand 2008; 52: 914–19. 10 Ong MEH, Ng FSP, Anushia P, et al. Comparison of chest compression only and standard cardiopulmonary resuscitation for out-of-hospital cardiac arrest in Singapore. Resuscitation 2008; 78: 119–26. 11 SOS-KANTO Study Group. Cardiopulmonary resuscitation by bystanders with chest compression only (SOS-KANTO): an observational study. Lancet 2007; 369: 920–26. 12 Van Hoeyweghen RJ, Bossaert LL, Mullie A, et al. Quality and effi ciency of bystander CPR. Resuscitation 1993; 26: 47–52. 13 Waalewijn RA, Tijssen JG, Koster RW. Bystander initiated actions in out-of-hospital cardiopulmonary resuscitation: results from the Amsterdam Resuscitation Study (ARRESUST). Resuscitation 2001; 50: 273–79. 14 Hallstrom A, Cobb L, Johnson E, Copass M. Cardiopulmonary resuscitation by chest compression alone or with mouth-to-mouth ventilation. N Engl J Med 2000; 342: 1546–53. 15 Rea TD, Fahrenbruch C, Culley L, et al. CPR with chest compression alone or with rescue breathing. N Engl J Med 2010; 363: 423–33. 16 Svensson L, Bohm K, Castrèn M, et al. Compression-only CPR or standard CPR in out-of-hospital cardiac arrest. N Engl J Med 2010; 363: 434–42. 17 Moher D, Liberati A, Tetzlaff J, Altman DG, and the PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Ann Intern Med 2009; 151: 264–69. 18 Stroup DF, Berlin JA, Morton SC, et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. JAMA 2000; 283: 2008–12. 19 Nichol G, Thomas E, Callaway CW, et al. Regional variation in out-of-hospital cardiac arrest incidence and outcome. JAMA 2008; 300: 1423–31. 20 Ewy GA. Continuous-chest-compression cardiopulmonary resuscitation for cardiac arrest. Circulation 2007; 116: 2894–96. 21 Gold LS, Eisenberg M. Chest-compression-only vs. standard cardiopulmonary resuscitation: shouldn’t we wait for more evidence? Prehosp Emerg Care 2008; 12: 406–09. Panel: Research in context Systematic review For this article, a rigorous search strategy was used to identify all clinical trials that prospectively randomised adults with out-of-hospital cardiac arrest to receive dispatcher-assisted chest-compression-only or standard CPR (including rescue ventilation), and all observational studies that distinguished between chest-compression-only and standard CPR in adults with out-of-hospital cardiac arrest. Interpretation Dispatcher-assisted chest-compression-only bystander CPR is associated with a 22% improved survival rate in adults with out-of-hospital cardiac arrest compared with standard CPR. CPR=cardiopulmonary resuscitation