Survival Following In-Hospital Cardiac Arrest Improving in the US

November 14, 2012

IOWA CITY, Iowa— More and more patients are surviving in-hospital cardiac arrest in the US and are doing so without any increases in the rate of clinically significant neurologic disability, according to the results of a new analysis [1]. Over a 10-year period, the percentage of survivors increased from 13.7% to 22.4%, while the rate of clinically significant neurological impairment declined from 32.9% to 28.1%.

"Patients with cardiac arrest are at a very significant risk of having neurological damage from the period of time when they are not receiving blood to the brain," lead investigator Dr Saket Girotra (University of Iowa Hospitals and Clinics, Iowa City) told heartwire . "So, for us to consider this a success, it's important for us to demonstrate not only that a greater number of people are getting saved from cardiac arrest, but that we are not just saving people who end up unable to function very well or who might be limited from a neurological standpoint. I think it's pretty remarkable that, whatever has happened in the past 10 years, those surviving actually have better neurological function."

Published in the November 15, 2012 issue of the New England Journal of Medicine, the study included an assessment of 374 hospitals participating in the Get with the Guidelines--Resuscitation registry between 2000 and 2009. In total, 84 625 patients with cardiac arrest at a general inpatient or intensive care unit (ICU) were included in the analysis. Overall, the initial cardiac-arrest rhythm was asystole or pulseless electrical activity in 79.3% of patients and ventricular fibrillation or ventricular tachycardia in 20.7% of patients.

In addition to the increasing rates of survival for cardiac arrest in the overall cohort, the temporal trends in survival were consistent among the different rhythm groups. The increase in survival was also consistent when analyzed by age (>65 years vs <65 years), race (black vs white), and sex. As noted, the rate of clinically significant neurologic disability declined over time, although rates of severe neurologic disability were unchanged.

To heartwire , Girotra said that mortality rates following cardiac arrest are not used as a hospital quality indicator, but there has been a great deal of interest in increasing survival rates for the past decade, if not longer. Despite the improvement over time, which provides a snapshot of how effective the quality improvements have been, he noted that survival after cardiac arrest remains low, with somewhat less than one in four patients surviving. Based on the present study, however, the researchers can't pinpoint exactly what changes have been made that led to the improvement.

"In my mind, the most important development that has happened is the recognition that high-quality chest compressions without interruption increase the chances of cardiac-arrest survival," said Girotra. "As a result, the American Heart Association guidelines, which have been revised twice in the past decade, emphasize the importance of chest compressions, the quality of chest compressions, and the fact that they shouldn't be interrupted."

Other changes that have occurred include quality-improvement efforts where hospitals can recognize cardiac arrest as soon as it happens so that appropriate resuscitation can be started, as well as the importance of timely defibrillation for patients in ventricular fibrillation or ventricular tachycardia. Another change, one that has not been well studied in the in-hospital setting, is postresuscitation care, that being what physicians and healthcare teams do once the patient is successfully revived. Some studies of cardiac-arrest cases have suggested that cooling might be beneficial in terms of reducing the risk of neurological complications, said Girotra.

The present analysis suggested that the improvement in survival was driven by changes in care and processes during the resuscitation and in the postresuscitation period. The rate of acute resuscitation survival improved, up from 42.7% in 2000 to 54.1% in 2009 (p<0.001), as did the rate of postresuscitation survival, increasing from 32.0% in 2000 to 42.9% in 2009 (p=0.001).

Some of the next steps will include identifying the specific factors driving the improvement in survival, said Girotra. This includes examining how hospitals address resuscitation efforts and how the resuscitation team is organized and works together, as well identifying how hospitals treat patients once they have been resuscitated. The hope is that by identifying the variables contributing to the improved survival they can be instituted at every hospital to standardize the processes of care.