Critical Care and Emergency Medicine researchers at Cooper University Hospital have published a research study in the Journal of the American Medical Association (JAMA), one of the leading medical journals. Their research, which was a large multicenter study of adult patients admitted to the Intensive Care Unit (ICU) after resuscitation from cardiac arrest, found that exposure to hyperoxia, or excessively high oxygen levels in the blood, is a common occurrence and an independent predictor of in-hospital mortality.
Conventionally, patients are administered 100% oxygen during cardiac arrest and resuscitation in attempts to get the heart restarted. However, after the heart is successfully restarted, the optimal level of oxygen has been controversial. The research indicates that you can get too much of a good thing, and excessive oxygen may be harmful.
“When a patient experiences cardiac arrest the brain cells are deprived of oxygen and this can result in permanent brain damage,” said Stephen Trzeciak, M.D., a co-author of the study and Emergency Medicine/Critical Care specialist at Cooper. “The brain damage may actually be intensified if too much oxygen is given when blood flow is restored. Previous studies in animals have shown this quite clearly, but our study is the first large scale report of outcomes in humans.”
The study included information from a critical care database of intensive care units (ICUs) at 120 U.S. hospitals. Patient inclusion criteria were older than 17 years of age, nontraumatic cardiac arrest, cardiopulmonary resuscitation within 24 hours prior to ICU arrival, and arterial blood gas analysis performed within 24 hours following ICU arrival. The study showed that patients with hyperoxia exposure had the highest mortality rate of all subjects in the study, even compared to those with persistently low oxygen levels.
“Our next step in this line of research is a clinical trial to determine what level of oxygenation is optimal,” explains J. Hope Kilgannon, M.D., Emergency Medicine specialist at Cooper and co-author of the study. “We want to use the information in this study to find better treatments and better outcomes for victims of cardiac arrest.”