TUESDAY, Feb. 19, 2008 (HealthDay News) -- Hospital patients who have the misfortune of suffering cardiac arrest at night or on the weekend are less likely to survive than those who have a heart attack during weekdays or weekday evenings, new research finds.
Although the study was not set up to pinpoint exactly why this is happening, it's likely that different staffing patterns, access to procedures, and other systemic issues may explain the difference in outcomes.
"Hospitals simply don't work the same at night as they do during the day," explained study author Dr. Mary Ann Peberdy, an associate professor of internal medicine and emergency medicine at Virginia Commonwealth University in Richmond. "There is enough data out there to suggest that this may be a process issue that is at least contributing, and probably contributing substantially."
The immediate cause of poor survival on nights and weekends may be one of timing: either there is a delay getting critical procedures or a delay in diagnosing the cardiac arrest in the first place.
"We're literally talking about a difference in seconds, which makes a significant impact," said Beth Mancini, associate dean of Undergraduate Nursing Programs at the University of Texas at Arlington. "It's time for hospitals to look critically at their processes."
Mancini is one of the "mothers" of the database used in this study, which is published in the Feb. 20 issue of the Journal of the American Medical Association.
According to the Institute of Medicine, up to 98,000 preventable in-hospital deaths occur every year in the United States, and the rate of medical errors is higher at night).
Previous, smaller studies have reported that heart attacks treated on a Saturday or Sunday are more deadly than those attended to during the week. Most of those had less than 100 patients, Peberdy said.
Canadian researchers have also found that strokes treated on the weekend are deadlier than those that are treated on a weekday.
The current study, the most comprehensive of its kind, analyzed survival rates for 86,748 adults who had suffered cardiac arrest events in one of 507 hospitals participating in the American Heart Association's National Registry of Cardiopulmonary Resuscitation.
Survival was divided into hourly time segments, with day/evening specified as 7 a.m. to 10:59 p.m., night as 11 p.m. to 6:59 a.m., and weekends as 11 p.m. Friday to 6:59 a.m. Monday.
Overall survival was 14.7 percent for nights/weekends, and 19.8 percent for weekdays.
Although individuals do undergo physiological changes at different times of the day, most of these changes were ruled out by the authors. And there were no survival discrepancies in the emergency department and trauma services.
"Emergency departments are one of the only places in the hospital that are typically staffed the same 24 hours a day and also have attending senior-level physicians available 24 hours a day," Peberdy said. "[Other areas of] the hospital often have doctors-in-training who respond to the cardiac arrest. That suggests this may be a process issue."
Other process issues may also be at fault. In one hospital, Mancini said, certain doors are locked at night, taking it longer to get a patient to a defibrillator. Even physician fatigue at the end of a shift could play a role.
"This paper really needs to go to hospitals, and the people who run them," Peberdy said.
Visit the American Heart Association for more on cardiac arrest.