People who breathe abnormally or gasp after collapsing from sudden cardiac arrest have a greater chance of surviving, researchers reported in Circulation: Journal of the American Heart Association.

"Gasping is extremely important because it is an indication that the brain is still alive, and it tells you that the person has a high chance of surviving," said Gordon A. Ewy, M.D., corresponding author of the study, professor and chief of cardiology at the University of Arizona and director of its Sarver Heart Center. "We need people to recognize sudden cardiac arrest, to call 9-1-1 and to start pressing on the chest."

However, bystanders often misinterpret gasping and other unusual vocal sounds to mean a person is breathing and, as a result, don't call 9-1-1 or begin lifesaving cardiopulmonary resuscitation, Ewy said. Thus, the authors hope the study's findings will lead to increasing bystander assistance to victims of primary cardiac arrest and to improving survival rates.

Gasping during cardiac arrest includes sounds described as snoring, snorting, gurgling, moaning, or agonized, barely, labored, noisy or heavy breathing.

The Arizona researchers sought to identify the frequency of gasping in sudden cardiac arrest victims and if the incidence of gasping would affect survival rates.

They examined data from two sources: Text messages from the Phoenix Fire Department Regional Dispatch Center from Jan. 1 to Jan. 31, 2008, included information on gasping in patients found by bystanders, whether their collapse was witnessed or not. The department's first-care reports on 1,218 witnessed patients from July 2004 through December 2007 provided the incidence of gasping upon or after the arrival of emergency medical service (EMS) personnel.

Among the study findings:

• Of 113 witnessed or unwitnessed cardiac arrests in January 2008, 39 percent had gasping.
• EMS first-care reports showed gasping in 32.8 percent of patients whose cardiac arrest came after EMS arrival; 20.1 percent when EMS arrived in less than 7 minutes; 13.9 percent with EMS arrival at 7 to 9 minutes; and 7.4 percent after 9 minutes.
• The odds of gasping decreased as EMS arrival time increased.
• Bystanders performed CPR on 40 percent of patients who gasped and on 39 percent who didn't gasp.
• Among the 481 patients who received bystander CPR, 39 percent of gaspers survived, but only 9.4 percent of those who didn't gasp survived.
• Among the 737 who did not receive bystander CPR, 21.1 percent of gaspers survived compared with just 6.7 percent of nongaspers.

CPR may cause a person who has stopped gasping to start gasping again. "This scares many people and they stop pressing on the chest," Ewy said. "This is bad because gasping is an indication that you're doing a good job."

Co-authors are: Bentley J. Bobrow, M.D.; Mathias Zuercher, M.D.; Lani Clark, B.S.; Vatsal Chikani, M.P.H.; Dan Donahue B.S., NREMT-P; Arthur B. Sanders, M.D.; Ronald W. Hilwig, D.V.M.; Robert A. Berg, M.D.; and Karl B. Kern, M.D.

The study was funded in part by a grant from the Arizona Department of Health Services Bureau of Emergency Medical Services.