The chances of surviving cardiac arrest in the hospital have improved nearly 12 percent in the last decade, possibly because of the introduction of new treatment approaches and guidelines, including therapeutic hypothermia. “Post Cardiac-Arrest Mortality Is Declining: A Study of the U.S. National Inpatient Sample 2001–2009,” which was published in Circulation, adds that the lowered mortality rate for cardiac arrest is a fact that sneaked up on us.
Researchers used the 2001–2009 U.S. National Inpatient Sample (NIS), a national hospital discharge database, to determine the mortality rates. In that time, nearly 1.2 million people were hospitalized with the condition. The in-hospital mortality rate decreased from 69.6 percent to 57.8 percent. “The mortality rate declined across all analyzed subgroups, including gender, age, race, and stratification by comorbidity,” the study states.
Researchers stress that the numbers are for people who survive long enough to make it to the hospital. Many aren’t so fortunate. The study cites new guidelines by the American Heart Association that stress CPR without mouth contact and easy-to-use automated external defibrillators for shockable arrhythmias. They also cite randomized trials that “showed that induced hypothermia reduces mortality and improves neurologic outcomes in patients with out-of-hospital ventricular fibrillation cardiac arrest.” The idea is to cool the body by IV saline, cooling blankets, or ice packs. That helps protect the brain until the patients can be slowly re-warmed.
Alejandro Rabinstein, MD, of the Mayo Clinic, lead researcher, tells Managed Care, “Our analysis … cannot discriminate between the various factors that may have contributed to the decline (better access to defibrillators, early coronary interventions, and therapeutic hypothermia, among others), thus providing indirect data to justify their application and expense. The improvement in mortality correlated with the gradual implementation of therapeutic hypothermia, but we cannot prove that this treatment was a major determinant for the improved outcomes.”
Still, changes in the care of these patients, rather than a change in the population itself, probably led to this decline in mortality. “The improvement in mortality was not explained by a change in the demographics or comorbidities of the patients with cardiac arrest,” says Rabinstein. “In fact, mortality diminished in recent years although resuscitated patients had more comorbidities at baseline. This is a reason not to give up on these patients before attempting aggressive resuscitation measures.”