Clinical paperThe impact of increased chest compression fraction on return of spontaneous circulation for out-of-hospital cardiac arrest patients not in ventricular fibrillation☆
Introduction
Survival to hospital discharge for out-of-hospital cardiac arrest (OOHCA) varies by community, but rarely exceeds 8%.1, 2 Bystander cardiopulmonary resuscitation (CPR) and defibrillation are two of only a few modifiable factors clearly associated with increased survival for OOHCA,3 and the importance of good quality CPR is increasingly being recognized.4, 5, 6, 7, 8 There is compelling evidence from animal studies suggesting that frequent and prolonged CPR interruptions have a detrimental effect on survival and neurological outcomes.9, 10, 11 Human studies also demonstrate that experienced CPR providers stop CPR frequently during out-of-hospital 12 and in-hospital resuscitation. 13 The 2005 emergency cardiovascular care guidelines that recommended changing the chest compression to ventilation ratio from 15:2 to 30:2 did thereby reduce interruptions to chest compressions.14 However, a growing number of reports suggest the benefit of chest compression-only CPR, avoiding interruptions for ventilation.15, 16, 17, 18, 19.
Compression fraction is defined as the proportion of CPR time spent providing chest compressions. A recent study by Christenson et al. evaluated the incremental benefit of higher chest compression fraction on survival to hospital discharge for OOHCA patients with an initial ECG rhythm of ventricular fibrillation or tachycardia (VF/VT).20 These authors described the relationship between increasing chest compression fraction and survival to hospital discharge, the highest survival (29%) being observed in the group of patients where 61–80% of CPR time was spent doing chest compressions. Survival is more common among patients with an observed initial rhythm of VF/VT compared with all other initial cardiac rhythms, but this VF/VT group generally represents less than 30% of all cardiac arrest patients.1, 2
The objective of the present study was to estimate the independent effect of chest compression fraction on return of spontaneous circulation (ROSC) in a cohort of OOHCA patients with an initial rhythm other than VF/VT.
Section snippets
Study design
This was an observational cohort study of OOHCA patients prospectively enrolled in the Resuscitation Outcomes Consortium (ROC) Cardiac Arrest Epistry. ROC is a clinical network of 11 regional centers distributed across North America conducting research in the fields of OOHCA and serious traumatic injury.21 The ROC cardiac arrest epidemiological registry or “Epistry” has been collecting population-based prospective data on OOHCA from more than 260 EMS agencies since December 2005.22 Information
Characteristics of study subjects
Among the 16,487 cardiac arrest cases of suspected cardiac etiology for which resuscitation was attempted, 14,795 were not witnessed by EMS and did not receive a shock before EMS arrival. Of these, 11,158 had an initial rhythm other than VF/VT and 2332 had CPR process measures, making them eligible for analysis. Outcome data were missing for 51 patients and 178 had been enrolled in an interventional study, leaving 2103 for the available data set (Fig. 1).
Overall patient and system
Discussion
This large multi-center prospective cohort study is the first to suggest that increased chest compression fraction results in a higher likelihood of ROSC in a population of OOHCA patients presenting with initial rhythms other than VF/VT—representing the majority of cardiac arrests in this setting. The observation is independent of other known potential predictors of ROSC.
The positive correlation, demonstrated by the smoothing spline representing the unadjusted incremental probability of ROSC (
Conflict of interest statement
- -
Siobhan Everson-Stewart, Jim Christenson, Douglas Andrusiek, Judy Powell, Tom P. Aufderheide, Robert Berg, and Ian G. Stiell have no conflict of interest to declare.
- -
Christian Vaillancourt, once received a small (<$25,000) unrestricted grant from Medtronic PhysioControl in 2001 to study to optimum placement of AEDs in the community.
- -
Sheldon Cheskes, once received a small honorarium from Zoll as a speaker.
- -
Graham Nichol, has the following conflicts of interests to disclose:
Research Grants:
Acknowledgements
The present multi-center observational cohort study was possible thanks to the same clinical research network (ROC) that collected data for the Christenson study on the effect of chest compression fraction in a cohort of VF/VT OOHCA patients.
We would like to acknowledge the professional care provided by first responders and paramedics, the hard labor of research team members at each participating sites, and the diligent supervision provided by the central data coordinating center study
References (26)
- et al.
CPR quality improvement during in-hospital cardiac arrest using a real-time audiovisual feedback system
Resuscitation
(2007) - et al.
Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest
Resuscitation
(2006) - et al.
Influence of chest compression rate guidance on the quality of cardiopulmonary resuscitation performed on manikins
Resuscitation
(2009) - et al.
Quality of out-of-hospital cardiopulmonary resuscitation with real time automated feedback: a prospective interventional study
Resuscitation
(2006) - et al.
Effect of implementation of new resuscitation guidelines on quality of cardiopulmonary resuscitation and survival
Resuscitation
(2009) Cardiac arrest—guideline changes urgently needed
Lancet
(2007)- et al.
Survival and neurologic outcome after cardiopulmonary resuscitation with four different chest compression-ventilation ratios
Annals of Emergency Medicine
(2002) - et al.
Oxygen delivery and return of spontaneous circulation with ventilation: compression ratio 2:30 versus chest compressions only CPR in pigs
Resuscitation
(2004) - et al.
Rationale, development and implementation of the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest
Resuscitation
(2008) - et al.
Regional variation in out-of-hospital cardiac arrest incidence and outcome
JAMA
(2008)
Canadian Cardiovascular Outcomes Research Team (CCORT) Cardiac arrest care and emergency medical services in Canada
Canadian Journal of Cardiology
Advanced cardiac life support in out-of-hospital cardiac arrest
New England Journal of Medicine
Adverse hemodynamic effects of interrupting chest compressions for rescue breathing during cardiopulmonary resuscitation for ventricular fibrillation cardiac arrest
Circulation
Cited by (220)
Out-of-Hospital Cardiac Arrest
2023, Emergency Medicine Clinics of North America2022 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces
2022, ResuscitationCitation Excerpt :The full text of this CoSTR can be found on the ILCOR website.8 Three RCTs9–11 and 21 observational studies12–32 were identified. The evidence identified was divided into 5 categories, and results are summarised in Table 2:
- ☆
A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2011.07.011.