Public Access Defibrillation by Trained Community Volunteers
Increases Survival for Victims of Cardiac Arrest
Orlando, FL., Nov. 11 – The number of survivors
of sudden cardiac arrest markedly increased when the
victims were helped by community volunteers trained
to perform not only CPR but also to use an automated
external defibrillator (AED), a device that shocks
an ineffectively beating heart back into normal rhythm,
according to the results of a large multi-center study
funded by the National Heart, Lung, and Blood Institute
(NHLBI) in collaboration with the American Heart Association.
Over an average 21.5 months, there were 29 cardiac
arrest survivors to hospital discharge in the group
assigned to CPR plus AED compared to 15 survivors
in the group assigned to CPR only. The results of
the Public Access Defibrillation (PAD) Trial are being
presented today in the Late Breaking Clinical Trials
section of the American Heart Association’s
Scientific Sessions 2003.
“Sudden cardiac arrest is a top killer of Americans.
This important study shows that lives can be saved
by training community volunteers to use external defibrillators,”
said Acting NHLBI Director Barbara Alving, M.D.
There are over 460,000 deaths from “out-of-hospital”
cardiac arrest each year in the United States, about
half of which occur suddenly. In cardiac arrest, the
heart stops beating effectively, blood does not circulate
and no pulse can be felt. The victim collapses suddenly
into unconsciousness. Heart attacks, which are caused
by a blockage of a coronary artery, can lead to cardiac
arrest. The most common underlying cause of sudden
cardiac arrest is an abrupt disorganization of the
heart’s rhythm called ventricular fibrillation,
which can be triggered by a heart attack or can just
represent a catastrophic rhythm disturbance. Unless
cardiac arrest is treated within minutes (defibrillation
or CPR followed by defibrillation), the victim will
die.
It is known that defibrillation by trained public safety
and emergency medical services (EMS) personnel is
a highly effective life-saving treatment for cardiac
arrest. However, it has not been known whether placing
automated external defibrillators in the community
and training lay persons to use them would prevent
additional deaths. The PAD Trial sought to answer
that question by evaluating survival of cardiac arrest
victims in areas where there were community volunteers
trained in CPR only, compared with survival of those
in areas where there were volunteers trained in both
CPR and the use of an AED.
The PAD Trial trained approximately 20,000 volunteer
rescuers at 24 sites in the U.S. and Canada. Each
site identified between 20 and 70 community units
with a potential for out-of-hospital cardiac arrests.
Some of these were large residential units–
such as apartment complexes; other sites were public
and included shopping centers, senior centers, office
buildings, and sports venues, etc. Each study unit
was randomly assigned to train volunteers in CPR only
(recognition of cardiac arrest symptoms, instruction
to call 911 for EMS support, and performance of CPR)
or in CPR and the use of an AED. Defibrillators were
distributed to the sites offering training in the
use of an AED. All volunteers received 2 to 4 hours
of initial training and most were retrained one or
more times during the study.
The majority of victims in both groups were men in
their late 60s or early 70s. Increased survival of
cardiac arrest victims was primarily found in the
CPR plus AED “public” sites -- rather
than in the residential locations. Survival rates
in residential study locations were very low and were
not improved by adding AEDs to the volunteer response
teams.
“This study was a major frontier to cross,”
said Joseph P. Ornato, M.D., chairman of the PAD steering
committee, who presented the findings in Orlando.
“We now have the results of the world’s
largest test of public access defibrillation. We trained
almost 20,000 volunteers. They did an incredible job
and there were no major injuries or serious safety
issues,” added Ornato who is Professor and Chairman
of the Virginia Commonwealth University Medical Center’s
Department of Emergency Medicine in Richmond.
Additional information from the PAD trial is still
being analyzed, including long-term survival results,
quality of life, mental function of survivors, and
the cost of implementing each type of system (costs
of identifying and training volunteers and placement
of AEDS).
An important next step in research on the use of AEDs,
said Ornato, is to test the safety and effectiveness
of home use of these devices. The NHLBI is currently
funding a multi-center 7,000 patient study designed
to evaluate whether providing the devices to families
of heart attack patients will improve survival if
a cardiac arrest occurs in that person’s home.
NHLBI is part of the National Institutes of Health
(NIH), the Federal Government's primary agency for
biomedical and behavioral research. NIH is a component
of the U.S. Department of Health and Human Services.
NHLBI press releases and other materials including
information about heart disease, high blood pressure,
and high blood cholesterol are available online at
www.nhlbi.nih.gov.
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