Hyperbaric Oxygen Therapy Extends Survival After Cardiac Arrest

FRIDAY, July 25 (HealthDay News) — High-dose hyperbaric oxygen therapy shows promise as a way to extend the window of opportunity to resuscitate a person whose heart has stopped during sudden cardiac arrest, a new study shows.

Researchers at the School of Medicine at the Louisiana State University Health Sciences Center in New Orleans report they used the technique to revive pigs up to 25 minutes after their hearts had stopped beating. In humans, if a patient's heart is not restarted through some means (CPR, medications or electric shock) within 16 minutes, 100 percent of patients die, according to American Heart Association statistics.

Sudden cardiac arrest is the leading cause of death of Americans.

"To resuscitate any living organism after 25 minutes of heart stoppage at room temperature has never been reported and suggests that the time to successful resuscitation in humans may be extended beyond the stubborn figure of 16 minutes that has stood for 50 years," study leader Keith Van Meter, a clinical professor of medicine at the LSU center, said in an university news release.

The findings were expected to be published in the August issue of Resuscitation.

In the study, LSU researchers stopped the heart of laboratory swine kept at room temperature and declared them dead from cardiac arrest. After waiting 25 minutes, they attempted advanced cardiac life support to resuscitate them accompanied by either normal or high doses of hyperbaric oxygen therapy. None of the swine received artificial breathing, CPR, medications, or electric shocks during their cardiac arrest.

Four of the six animals given high-dose hyperbaric oxygen, a dose one-third greater in strength than what is normally given to humans, were revived after a two-hour resuscitation period. No others survived.

"The present study shows that short-term, high-dose hyperbaric oxygen is an effective resuscitation tool and is safe in a small multi-place hyperbaric chamber," Van Meter said. "A rehearsed team can easily load a patient in cardiopulmonary arrest into a small multi-place chamber in the pre-hospital or hospital setting without interrupting CPR or advanced cardiac life support. Successful resuscitation at 25 minutes suggests that if high-dose hyperbaric oxygen is used at the current ACLS limit of 16 minutes, a greater survival may be achieved in humans and allow application of more definitive treatment such as clot-dissolving drugs."

Future studies are planned to evaluate this technique.

— Kevin McKeever

SOURCE: Louisiana State University Health Sciences Center New Orleans, news release, July 21, 2008

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Sudden cardiac arrest means the heart has stopped beating. See Answer

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