March 10, 2009
Children, teens most likely to survive nontraumatic out-of-hospital cardiac arrest
Children and adolescents are twice as likely as infants or adults to survive a nontraumatic, out-of-hospital cardiac arrest, a University of Iowa-led research team has found in one of the largest studies of this type of cardiac arrest.
The investigators also found that the survival rate for this type of cardiac arrest for infants younger than age 1 was lower than the survival rate for adults. The findings, which have implications for improving treatment among young patients, were published online March 9 by Circulation: Journal of the American Heart Association.
The type of cardiac arrest cases studied were not caused by respiratory arrest or traumatic injury but occurred outside of hospitals. In particular, the study found that 6.4 percent of pediatric patients versus 4.5 percent of adults who experience out-of-hospital cardiac arrest survived to be discharged from the hospital, a statistically significant difference.
The findings refute a widespread misconception that cardiac resuscitation in not effective in young people, said Dianne Atkins, M.D., the study's lead author who is a professor of pediatrics at the UI Roy J. and Lucille A. Carver College of Medicine and a pediatric cardiologist with UI Children's Hospital and the UI Heart and Vascular Center.
"Previously, if you talked to most emergency medicine doctors and emergency medicine technicians, they would say that children almost never survive a cardiac arrest," Atkins said. "What we showed is that children older than age 1 and teenagers, in fact, do better than adults."
Researchers discovered the findings after analyzing data from Dec. 1, 2005, through March 31, 2007, at 11 geographic areas (eight in the United States, three in Canada) participating in the Resuscitation Outcomes Consortium (ROC), a group that conducts clinical trials and other outcome research involving cardiopulmonary arrest and severe traumatic injury.
Using the ROC Epistry-Cardiac Arrest Database, Atkins and colleagues looked at the incidence, characteristics and outcomes of out-of-hospital cardiac arrest among three pediatric groups, defined as infants under age 1, children ages 1 to 11, and adolescents ages 12 to 19.
Among pediatric patients treated by emergency medical service personnel and treated with CPR, 3.5 percent of infants, 10.4 percent of children, and 12.6 percent of adolescents survived to discharge. In actual numbers, the survivors represented eight of 230 infants, 14 of 135 children and 17 of 135 adolescents.
Atkins noted that many previous analyses of low pediatric out-of-hospital cardiac arrest survival placed infants together with older pediatric patients. In the future, researchers should separate infants from older pediatric patients in epidemiologic studies, and more aggressively address their treatment, she said.
"We put a lot of effort into developing better therapies and better ways to resuscitate adults," Atkins said. "We also need to put that same effort into children because they actually do have a slightly higher survival."
The study also found that the incidence of pediatric cardiac arrest per 100,000 person-years was approximately 73 for infants, four for children, and just over six for adolescents, compared to nearly 127 for adults.
Atkins said previous related pediatric cardiac arrest studies have covered a single geographic region, usually a large metropolitan area. Because out-of-hospital cardiac arrest is uncommon in children, a single-site study often required many years to accrue sufficient numbers of cases for statistically significant assessment.
The ROC study cases totaled 25,405 adults and 624 people younger than age 20, including 277 infants, 154 children and 193 adolescents. These case numbers included cases in which the individuals were deemed deceased and EMS personnel did not provide treatment, as well as the cases of the 230 infants, 135 children and 135 adolescents who received CPR treatment from EMS personnel.
"The advantages of this study were that we collected a very large number of out-of-hospital cardiac arrests in children from geographically diverse sites, over a very short time," Atkins said.
The study also involved researchers from the University of Washington, Oregon Health and Science University, University of Ottawa, Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine.
The study was supported by the National Institutes of Health, the Canadian Institutes of Health Research, Defense Research and Development Canada, the American Heart Association and the Heart and Stroke Foundation of Canada.
NOTE TO EDITORS: This release is an adaptation of a release provided by the American Heart Association.
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