Resuscitation Outcomes Consortium

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Resuscitation Outcomes Consortium
Increased Chest Compression Fraction is
Associated with Increased Return of Spontaneous
Circulation in Non-Ventricular Fibrillation
Out-of-Hospital Cardiac Arrest
Victims Christian Vaillancourt University of
Ottawa For the ROC Investigators CAEP, Calgary
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Co-Authors

• Siobhan Everson-Stewart University of
  Washington
• Jim Christenson University of British Columbia
• Douglas Andrusiek University of British
  Columbia
• Judy Powell University of Washington
• Graham Nichol University of Washington
• Sheldon Cheskes Sunnybrook-Osler Center
  Prehospital Care
• Tom Aufderheide Medical College of Wisconsin
• Robert Berg University of Arizona
• Ian Stiell University of Ottawa
• and the ROC investigators
• No conflict of interest to declare

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ROC Site Map
12 Participating Sites
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ROC Cardiac Arrest Epistry

• Population Base 21,400,000
• To facilitate ROC trials
• To define incidence and outcome
• To describe the relationships between
• resuscitation performance and EMS
• To evaluate the relationships between
• outcome and other factors

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ROC Funding Partners
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Background

• Cardiac arrest remains the primary cause of
  death,
• 310,000 annually in the US
• 85 of cardiac arrests occur at home
• Overall survival to hospital discharge rarely
  exceeds 8
• CPR quality is an important modifiable factor for
  survival

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Introduction

• Chest compression fraction is the proportion of
  time spent providing chest compressions during
  CPR
• Increased CCF is independently associated with
  better survival in VF/VT cases Christenson,
  submitted
• Unclear if this association is present for
  non-VF/VT cases

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Objectives
We evaluated the effect of CCF on return of
spontaneous circulation (ROSC) in out-of-hospital
cardiac arrest (OOHCA) patients with non-VF/VT
rhythms
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Methods Design and Setting

• Data analysis of patients prospectively enrolled
  in the ROC Epistry between
  December, 2005 and June, 2007
• 10 US and Canadian sites participating in ROC
• (Urban communities with ALS and BLS-D EMS)
• -Vancouver -Portland
• -Seattle -Dallas
• -Toronto -Iowa
• -Pittsburgh -Milwaukee
• -Ottawa/OPALS -Alabama

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Methods - Population

• Adult (gt 18 years of age)
• OOHCA of no obvious cause
• gt1min of CPR with CPR process measured
• Initial non-VF/VT rhythm
• Not witnessed by EMS
• No AED shock prior to EMS arrival
• Not enrolled in ROC interventional study

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Methods Data Collection

• We reviewed the first 5 minutes of electronic CPR
  records following electrode application
• Included minute during which shock analysis
  occurred

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Methods Chest Compression Fraction

• Proportion of compressions/min with no pulse
• (averaged over all minutes)
• Calculated by AED software
• Pause in compression defined as
• gt 3 sec (Medtronic)
• gt 2 sec (Phillips and Zoll)
• CCF Categories
• (0-40, 41-60, 61-80, 81-100)

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Example of CPR Process Measures
xx
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Methods Primary Outcome Measure

• Return of Spontaneous Circulation (ROSC)
• Determined to be present if
• Noted on the time record
• Documented on ED arrival
• CPR was stopped due to ROSC

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Methods Analyses

• Descriptive statistics
• Patient and system characteristics
• Logistic regression analyses
• Odds Ratio (95 CI) for the effect of
  CCF
• on ROSC, adjusted for
• Age Bystander CPR
• Gender Bystander witnessed status
• Location of arrest Chest compression rate
• Time 911 call to AED turned on

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RESULTS Selection of Cases
Adult OOHCA of No Obvious Cause with
Resuscitation Attempt N 16,487
Arrest Witnessed by EMS N 1,456
Arrest Not Witnessed by EMS N
15,031
AED Shock Before EMS Arrival N 236
No AED Shock Before EMS Arrival N 14,795
Initial Rhythm VF/VT N
3,637
Initial Rhythm other than VF/VT N
11,158
Enrolled in ROC Interventional Study
N 178
Not Enrolled in ROC Interventional Study
N 10,980
Missing Vital Status N 51 Missing CPR
Process Data N 8,807
1 min of CPR Process Measured N 2,122
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Contribution of Cases by Site N 2,122
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Patient and System Characteristics
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Patient and System Characteristics
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Patient and System Characteristics
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Prediction of ROSC (Adj. OR, 95CI) and ROSC by
CCF Category N 2,122
Prediction of ROSC (Adjusted OR, 95 CI) by CCF
category
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Predictors of Pre-hospital ROSC for
First Rhythm non-VF/VT N 2,122
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Discussion

• Strengths
• Ability to measure CPR processes
• Large cohort of cases obtained from
• international collaborative consortium
• Dedicated team of paramedics and analysts
• well-versed in research procedures
• First study to suggest effect of CCF on ROSC
• for non-VT/VF victims

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Discussion

• Limitations
• Uneven contribution of cases by site
• Local practices may influence CCF by site
• Exclusion of CPR info prior to AED placement
• Potential bias introduced by significant number
• of cases with missing CPR process data
• ROSC may not be suitable surrogate
• for survival to hospital discharge

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Conclusions
Non VF/VT OOHCA victims usually deemed
unsalvageable This is the first study suggesting
that increased CCF for OOHCA victims with initial
rhythm other than VF/VT is associated with
increased likelihood of ROSC
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Sample Size Calculation for
Survival Analyses