Study: Patients recall vivid memories during cardiac arrest

Survivors of cardiac arrest may be at risk for post-traumatic stress disorder or other mental health issues because they maintained vivid memories of their near-death experiences, according to a recent study.

What happens to the mind during cardiac arrest and what it remembers is an understudied area. Sam Parnia, MD, director of resuscitation research at the State University of New York at Stony Brook, and colleagues sought to understand what occurs. They interviewed 140 survivors of cardiac arrest; interviews were conducted both in-hospital and after discharge. Sixty-seven percent of patients were men and patients' ages ranged from 21 to 94. None of the patients showed clinical signs of consciousness when cardiopulmonary resuscitation was being administered to them.

Survivors were asked questions such as "Did you see, or feel surrounded by, a brilliant light?" and "Did you feel separated from your body?"

The researchers verified patients' responses with medical records and other reports. Among the 140 patients interviewed, 101 reported perceived awareness or memories during their cardiac arrest, with 2 percent reporting recall of specific auditory and visual sensations during their resuscitation.

The study also found that:

• 27 percent said they felt events were speeding up or slowing down;
• 22 percent reported feeling a sense of peace or pleasantness;
• 13 percent said their senses felt more vivid than usual;
• 13 percent said they felt separated from their bodies;
• 0 percent said they saw scenes from the future.

Thematically, patients reported feeling like they were dragged through water, seeing plants and animals, seeing golden light, seeing family members and having deja vu experiences.

The results of the study were published in a recent issue of the medical journal Resuscitation.

Over 420,000 out-of-hospital cardiac arrests occur in the United States every year, with about 80 percent of these taking place at home. A cardiac arrest is different from a heart attack; it occurs when electrical impulses to the heart become chaotic, which causes the heart to suddenly stop. A heart attack occurs when the blood supply to the heart muscle becomes blocked; a heart attack can cause cardiac arrest.

Dr. Parnia said the findings indicate that people may have vivid near-death experiences, but struggle to recall them due to brain injury or sedative drugs. Health care providers resuscitating patients undergoing cardiac arrest should recognize that although patients may not show physical signs of consciousness, they may still be aware of their surroundings, he said.

"Health care providers should be cognizant of these things much the same way we treat patients undergoing anesthesia," he said. "We should not assume that because one is in cardiac arrest and they look dead they have no awareness whatsoever. Our study shows that death is not a black-and-white experience or that it is a finite moment. Our study indicates we have the potential to bring people back even if they have technically died."