Chest Compression Fraction Determines Survival in Patients With Out-of-Hospital Ventricular Fibrillation

Jim Christenson, MD; Douglas Andrusiek, MSc; Siobhan Everson-Stewart, MS; Peter Kudenchuk, MD; David Hostler, PhD; Judy Powell, BSN; Clifton W. Callaway, MD, PhD; Dan Bishop; Christian Vaillancourt, MD, MSc; Dan Davis, MD; Tom P. Aufderheide, MD; Ahamed Idris, MD; John A. Stouffer; Ian Stiell, MD, MSc; Robert Berg, MD; the Resuscitation Outcomes Consortium Investigators

From the University of British Columbia (J.C., D.A.), Vancouver, British Columbia, Canada; Emergency and Health Services Commission of British Columbia (J.C., D.A., D.B.), Vancouver, British Columbia; University of Washington (S.E.-S., P.K., J.P.), Seattle, Wash; University of Pittsburgh (D.H., C.W.C.), Pittsburgh, Pa; Department of Emergency Medicine (C.V., I.S.), University of Ottawa, Ottawa, Ontario, Canada; University of California at San Diego (D.D.); Medical College of Wisconsin (T.P.A.), Milwaukee, Wis; University of Texas Southwestern Medical Center at Dallas (A.I.); Central Washington University (J.A.S.), Ellensburg, Wash; and University of Arizona (R.B.), Tucson, Ariz.

Correspondence to Dug Andrusiek, MSc, Emergency and Health Services Commission of British Columbia, 302–2955 Virtual Way, Vancouver, British Columbia, Canada V5M 4X6. E-mail dug.andrusiek@gov.bc.ca

Received January 23, 2009; accepted July 10, 2009.

Abstract

Background— Quality cardiopulmonary resuscitation contributes to cardiac arrest survival. The proportion of time in which chest compressions are performed in each minute of cardiopulmonary resuscitation is an important modifiable aspect of quality cardiopulmonary resuscitation. We sought to estimate the effect of an increasing proportion of time spent performing chest compressions during cardiac arrest on survival to hospital discharge in patients with out-of-hospital ventricular fibrillation or pulseless ventricular tachycardia.

Methods and Results— This is a prospective observational cohort study of adult patients from the Resuscitation Outcomes Consortium Cardiac Arrest Epistry with confirmed ventricular fibrillation or ventricular tachycardia, no defibrillation before emergency medical services arrival, electronically recorded cardiopulmonary resuscitation before the first shock, and a confirmed outcome. Patients were followed up to discharge from the hospital or death. Of the 506 cases, the mean age was 64 years, 80% were male, 71% were witnessed by a bystander, 51% received bystander cardiopulmonary resuscitation, 34% occurred in a public location, and 23% survived. After adjustment for age, gender, location, bystander cardiopulmonary resuscitation, bystander witness status, and response time, the odds ratios of surviving to hospital discharge in the 2 highest categories of chest compression fraction compared with the reference category were 3.01 (95% confidence interval 1.37 to 6.58) and 2.33 (95% confidence interval 0.96 to 5.63). The estimated adjusted linear effect on odds ratio of survival for a 10% change in chest compression fraction was 1.11 (95% confidence interval 1.01 to 1.21).

Conclusions— An increased chest compression fraction is independently predictive of better survival in patients who experience a prehospital ventricular fibrillation/tachycardia cardiac arrest.

Key Words: heart arrest • cardiopulmonary resuscitation • fibrillation • survival