Yet another study has shown that cardiopulmonary resuscitation (CPR) by lay people that does not include mouth-to-mouth breathing yields a better chance of survival for people who suffer cardiac arrest outside a hospital. But even with the technique, which improves the odds of survival by as much as 60%, a person's chances of survival are still "dismal," less than about 15%, Arizona researchers reported Tuesday. Among the reasons for poor survival are delays in getting resuscitation started, the unwillingness of lay people to use CPR, and lack of knowledge about how to do it.
There are many reasons why mouth-to-mouth may not be advisable for lay people, beyond the fact that many simply do not want to perform it. Among other things, there is a rapid deterioration of blood flow that occurs during even brief disruptions of chest pumping, the long ramp-up time for resumption of normal flow when compressions are begun again after a pause, the significant amount of time necessary to perform breathing and the critical importance of keeping blood flow to the brain going during a heart attack. Moreover, most heart attack victims gasp for air every 15 to 20 seconds, and that provides more oxygen than mouth-to-mouth, experts said.
About 300,000 Americans suffer out-of-hospital cardiac arrests each year. Survival rates are highly variable, but are consistently low.
In 2007, a Japanese study showed that compression-only CPR could nearly double the survival rate among patients who had a witnessed cardiac arrest. In July, two studies, one in Washington and one in Sweden, found similar results.
In 2005, health authorities in Arizona began a campaign to increase the use of CPR by bystanders, emphasizing the use of compression-only CPR for those who were reluctant to touch lips. In Tuesday's Journal of the American Medical Assn., Dr. Bentley J. Bobrow of the Arizona Department of Health Services and his colleagues reported results from that effort. The team analyzed data on 4,415 adults in the state who suffered out-of-hospital cardiac arrests between January 2005 and December 2009. Emergency responders were trained to determine whether a patient had been given CPR by a bystander and, if so, what form it took.
The team found that survival to hospital discharge occurred in only 5.2% of those who received no bystander CPR, 7.8% of those who received conventional CPR and 13.3% of those who received compression-only CPR. During the period, the proportion of cardiac arrest victims who received bystander CPR rose from 28.2% to 39.9%, presumable because of the public awareness campaign. Among those who received CPR, the proportion receiving compression-only CPR rose from 19.6% to 75.9%.
The American Heart Assn. and other groups now recommend that bystanders who do not wish to perform mouth-to-mouth be encouraged to give compression-only CPR. New guidelines for CPR are expected to be issued later this month and they will most likely give greater emphasis to compression-only CPR.
-- Thomas H. Maugh II / Los Angeles Times