(Seattle, Washington) November 20, 2009—Emergency medical
service (EMS) providers in the United States assess an estimated
350,000 cardiac arrests each year. Only 5 to 10 percent of people
who have sudden cardiac arrest survive. Better quality
cardiopulmonary resuscitation (CPR) provided by prehospital EMS
providers may be associated with better patient outcome. The
Resuscitation Outcomes Consortium (ROC) is the largest clinical
research network to study prehospital treatments for cardiac arrest
in the United States and Canada. ROC conducted the first randomized
study to assess if real-time audio-feedback, during the EMS
prehospital course of care, would improve clinical outcome. Results
of the study were presented on November 15th during the
Resuscitation Science Symposium 2009 program.
Twenty-one EMS agencies from three ROC regions in the US and
Canada (King County, WA; Pittsburgh, PA; Thunder Bay, ON) enrolled
1,521 treated non-traumatic cardiac arrest patients over the course
of 25 months. The study included all eligible patients who received
EMS rescue shocks or chest compressions. Participating agencies
were provided by the manufacturer with commercially available
devices equipped with visual and audible real-time feedback
coaching the quality of CPR. Agencies provided training to their
EMS providers in a manner consistent with local policy and
standards.
In this prospective randomized trial, EMS agencies were assigned
to one of two treatment groups, audible 'feedback on' or 'feedback
off.' When feedback was on, real-time audible and visual prompts
advised providers to conform CPR to American Heart Association
(AHA) guidelines. The assignment changed every two to seven months,
depending on the expected number of treated cardiac arrests. When
assigned to 'feedback on,' EMS providers muted the audible coaching
in 15% of cases. Baseline characteristics of patients randomized to
each of the two groups were comparable.
The primary objective of the study was to determine the
proportion of patients with a return of spontaneous circulation
(ROSC) during the prehospital course of EMS care. ROSC was defined
as the presence of a palpable pulse in any blood vessel for any
length of time. The difference observed between the two study
groups was not statistically significant: return of spontaneous
circulation occurred in 48.0% of 'feedback on' and 48.8% with
'feedback off.'
Secondary outcomes of the study were also reported:
- Survival to hospital discharge was not significantly different
between the two treated groups, with 10.6% of 'feedback on' and
12.2% of 'feedback off' surviving.
- Compliance with AHA recommendations for quality CPR improved
modestly when assigned to 'feedback on', with an observed reduction
in compression rate, an increase in the depth of compressions, and
an increase in the amount of time spent doing CPR.
Researchers will further analyze and publish the final data in
the coming months.
"In this trial, the quality of CPR in the 'feedback off' group
was substantially better than has been previously reported for
prehospital EMS and may suggest that the potential clinical benefit
of real-time CPR feedback is limited in EMS systems with
well-trained rescuers," said ROC principal investigator, Clif
Callaway, M.D., Ph.D., associate professor and vice chair of
emergency medicine at the University of Pittsburgh. Dr. Callaway
also noted, "This study's attention to the quality of CPR may well
have affected the results of both arms of the study, regardless of
whether real-time feedback was turned on or off."
When administered as soon as possible, CPR and, in some cases,
rapid treatment with a defibrillator – a device that sends an
electric shock to the heart to try to restore its normal rhythm
– can be lifesaving. When delivered by EMS professionals, CPR
is a combination of chest compressions, to keep oxygen-rich blood
circulating until an effective heartbeat is restored, and rescue
breathing. Lay bystanders are encouraged to immediately begin CPR
using only chest compressions until professional help arrives,
according to the American Heart Association.
ROC research focuses on treatments for patients with
life-threatening traumatic injury or cardiac arrest in real-world
settings, typically where patients collapse or are critically
injured, before they reach the hospital. ROC clinical trials are
conducted under strict U.S. FDA and Canadian guidelines.
SOURCE