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NEW YORK (Reuters Health) - Early advanced life support measures and improved procedures have boosted survival following "out-of-hospital" cardiac arrest, according to a study conducted in Japan and reported Tuesday in the medical journal Circulation.
"This study is important," lead investigator Dr. Taku Iwami told Reuters Health "because it demonstrates that improvements of the 'chain of survival' really increase survival after out-of-hospital cardiac arrest."
Iwami, of Kyoto University Health Service, and colleagues studied data from 1998 to 2006 on 42,783 out-of-hospital cardiac arrests involving adults in whom resuscitation attempts were made. They analyzed outcome in 8,782 presumed cardiac arrests witnessed by bystanders, in order to examine how efforts to improve emergency medical services (EMS) affected outcome.
During the study period, Japanese citizens were trained in cardiopulmonary resuscitation (CPR), dispatcher instruction in CPR was introduced and procedures were changed to allow EMS personnel to deliver shocks with a defibrillator without online physician oversight and to place breathing tubes into the trachea to protect the patient's airway and provide a means of mechanical ventilation.
Over the study period, one-month survival of bystander-witnessed cardiac arrests rose from 5 percent to 12 percent, the researchers report.
In addition, the median time from collapse until a call for medical help dropped from 4 minutes to 2 minutes. Bystander-initiated CPR increased from 19 percent to 36 percent, the median interval for CPR dropped from 9 to 7 minutes, and time to first shock fell from 19 to 9 minutes.
Factors associated with improved outcome, overall, were earlier CPR and earlier placement of breathing tubes.
"We hope this study encourages other EMS systems to start or continue their efforts to improve their EMS systems," Iwami commented. Feedback "is very important to EMS personnel and people in general, to let them know that these efforts result in saving lives."
In the United States, nearly 300,000 cardiac arrest victims are treated outside the hospital by EMS per year, according to the American Heart Association.
SOURCE: Circulation, February 10, 2009.