SmartCPR Trial: An Analysis of a Waveform-Based Automated External Defibrillation (AED) Algorithm on Survival From Out-of-Hospital Ventricular Fibrillation

Cardiac Arrest Clinical Trial

— SmartCPR  

Official title:

An International, Randomized, Controlled Prehospital Trial of a Waveform-Based Automated External Defibrillation Algorithm for the Management of Ventricular Fibrillation

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00535106
• Other study ID #: H05290
• Status: Completed
• Phase: N/A
• First received: September 25, 2007
• Last updated: October 18, 2009
• Start date: May 2006
• Est. completion date: June 2009

Study information

• Verified date: October 2009
• Source: New York City Fire Department
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Federal Government
• Study type: Interventional

Clinical Trial Summary

This study is designed to examine the impact of an available technology within an automated external defibrillator (AEDs) to improve survival following out-of-hospital cardiac arrest for patients presenting in ventricular fibrillation.

Description:

The delivery of an electrical shock, termed defibrillation, has long been recognized as one of the critical "links" in the "Chain of Survival" following out-of-hospital cardiac arrest. This is particularly the case for patients who present in ventricular fibrillation (VF), a state of constant and yet uncoordinate firing of the lower portions of the heart (the ventricles), and the ability to treat these patients with defibrillation prior to their arrival in the hospital has remained one of the reasons why this group represents the patients who are most likely to survive an out-of-hospital cardiac arrest.

Though this technology has been successfully utilized in the prehospital setting for more than forty years, the long-held belief that "immediate defibrillation" was the optimal treatment for all patients has now come into question.

Following research done in locations such as Seattle, WA and Oslo, Norway, there came a recognition that some patients (particularly those who have been in cardiac arrest for 4-5 minutes prior to EMS arrival) may actually benefit from a period of CPR prior to defibrillation ("delayed defibrillation"). This has to do with the changes that take place within the heart and even at the level of the cells within the heart following the onset of VF. After several minutes of VF, the cells within the heart have been deprived and depleted of oxygen and other energy-containing molecules, and there has been a build-up of other substances such as acids and potassium. By providing CPR prior to defibrillation, it is thought that the patient's heart may be provided with enough oxygen and other energy-containing molecules, making it more likely that the heart will respond favorably to defibrillation.

Yet this is not necessarily true for all VF patients. Other data from patients whose collapse and cardiac arrest were witnessed and for whom defibrillation was able to be provided quite rapidly (i.e. those in airports, airplanes, and casinos) demonstrate a very high survival rate when compared to those patients who have been in arrest for a longer period. This suggests that there are patients who are best treated with immediate defibrillation and those who are treated with "delayed defibrillation."

The problems for modern emergency medical services (EMS) systems include determining just when the VF began, the impact of bystander CPR, the patient's overall condition at the time of the cardiac arrest, and the time interval from the 911 call until the arrival of the EMS providers (EMTs and paramedics) at the side of the patient.

By choosing to provide immediate defibrillation to all patients, in hopes of benefiting those who are most likely to respond to defibrillation and to survive, an EMS system would simultaneously be choosing to provide less than ideal treatment to those patients who are likely to benefit from "delayed defibrillation." Conversely, choosing to provide "delayed defibrillation" to all patients likely treats the larger percentage of VF patients in any EMS system appropriately, yet it potentially delays life-saving treatment from those who are most likely to survive (the patients who would benefit from immediate defibrillation).

Research involving the mathematic properties of the VF waveform (something that the human eye cannot calculate) have led to the development of computer algorithms that may predict, based on the calculated mathematical "score" of the VF, whether a patient is likely to respond more favorably to immediate defibrillation or delayed defibrillation. Such a technology could, therefore, seem to be able to recommend every patient to the treatment that is best for their individual condition, and it would follow that such individual treatment may improve survival from VF cardiac arrest overall.

This study is designed to examine the effect of just such a technology on VF patients presenting to EMS providers in New York, NY and London, England.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 900
• Est. completion date: June 2009
• Est. primary completion date: June 2009
• Accepts healthy volunteers: No
• Gender: Both
• Age group: N/A and older

Eligibility

Inclusion Criteria:

• initial treatment includes application of a study AED

• complete initial waveform analysis

• presenting rhythm is ventricular fibrillation

• arrest of cardiac etiology

Exclusion Criteria:

• arrest of noncardiac etiology

• initial treatment with a non-study defibrillator

• missing AED data

• age <18 (London only)

• resuscitation terminated due to a DNR order / decision

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Double Blind (Subject, Caregiver), Primary Purpose: Treatment

Related Conditions & MeSH terms

• Cardiac Arrest
• Heart Arrest
• Ventricular Fibrillation

Intervention

Device:
• Automated external defibrillator (Philips FR2+ AED)
Patients in this arm will be provided with immediate defibrillatory shock coupled with otherwise standard resuscitative efforts.
• SmartCPR
Patient in this arm will be treated with standard resuscitation efforts except that the first AED analysis will utilize an waveform-based algorithm to recommend either immediate defibrillation or delayed defibrillation for each patient.

Other:
• Delayed defibrillation
In New York City only, all patients not initially treated by study personnel will receive other regional standard for resuscitation - delayed defibrillation.

Locations

Country	Name	City	State
United Kingdom	London Ambulance Service	London	England
United States	New York City Fire Department	New York	New York

Sponsors (3)

Lead Sponsor	Collaborator
New York City Fire Department	London Ambulance Service, Philips Medical Systems

Countries where clinical trial is conducted

United States,  United Kingdom, 

References & Publications (60)

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* Note: There are 60 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Survival to Hospital Discharge		Variable (depends upon interval needed for hospital admission and discharge)	No
Secondary	Survival to hospital admission		within hours from the time of arrest	No
Secondary	Return of spontaneous circulation (ROSC) in prehospital setting		Variable (depends on EMS contact time)	No
Secondary	Neurological status among survivors		Variable (measured at hospital discharge)	No
Secondary	Survival (defined as ROSC, survival to hospital admission, and survival to hospital discharge) as compared to a "delayed defibrillation" cohort in NYC		Variable (depends upon interval needed for hospital admission and discharge)	No
Secondary	Impact of CPR interval on VF waveform characteristics		Immediately after CPR interval	No
Secondary	Utility of AED algorithm and VF characteristics among EMS-witnessed arrests		Variable (some immediate data, some depends upon interval needed for hospital admission and discharge)	No
Secondary	Utility of this AED technology and VF characteristics among pediatric patients		Variable (some immediate data, some depends upon interval needed for hospital admission and discharge)	No
Secondary	Impact of bystander CPR on VF waveform characteristics		Immediate (taken from data during arrest)	No
Secondary	Comparison of EMS response times to VF waveform characteristics		Immediate (data obtained during EMS response and arrest period)	No
Secondary	Frequency of unmanageable airways in out-of-hospital cardiac arrest patients		Immediate (measured at the time of arrest)	No
Secondary	Impact of patient race upon the provision of bystander CPR, VF waveform characteristics, and survival		Variable (depends upon interval needed for hospital admission and discharge)	No
Secondary	Relationship between presenting and interval waveform capnography readings and survival		Variable (depends upon interval needed for hospital admission and discharge)	No
Secondary	Frequency of organ donation among out-of-hospital cardiac arrest patients transported to the hospital who do not survive to hospital discharge		Variable (depends upon interval needed for hospital admission and discharge)	No
Secondary	Waveform characteristics among patients presenting in secondary VF (initial presenting rhythm asystole or pulseless electrical activity)		Immediate (derived from data collected during the arrest)	No
Secondary	Description of and outcomes of patients for whom intraosseous access is utilized during the cardiac arrest		Variable (depends upon interval needed for hospital admission and discharge)	No
Secondary	Utstein comparison of two cities (London and New York)		Variable (depends upon interval needed for hospital admission and discharge)	No
Secondary	Impact of bystander CPR on survival as a function of response time		Variable (depends upon interval needed for hospital admission and discharge)	No
Secondary	Association between ambient small particle (PM2.5) pollution and cardiac arrest indicence in New York City		To be determined by modelling	No

External Links

•   FDNY webpages specific to the SmartCPR Trial