Increased Diversion Hours Indicates Declining Emergency Department Capacity; Elderly Disproportionately Affected
Washington, DC — Two new studies published online by the Annals of Emergency Medicine document the extent of ambulance diversions signaling a lack of capacity in the emergency medical care system. One study is national in scope, while the other looks at the problem on the local level, but both uncover clues about the causes and characteristics of ambulance diversion that could help policymakers address the problem.
Centers for Disease Control and Prevention (CDC) researchers, in the first national study of ambulance diversions, found about one ambulance in the United States is diverted every minute from its originally intended emergency department because it was overcrowded and could not safely care for another sick or injured patient. The research is based on the 2003 National Hospital Ambulatory Medical Care Survey, an annual probability sample survey of U.S. hospital emergency departments and outpatient departments.
About 16.2 million patients arrived by ambulance to emergency departments in 2003, which represent 14 percent of the total emergency department visits made that year, according to the CDC. Of those visits, seniors comprised nearly 40 percent, the largest group transported by ambulance to emergency departments.
"Considering the biggest users of ambulance services are people over age 65, and the number of seniors is expected to substantially increase over the next decade, ambulance diversion could disproportionately affect this age group," said the study’s lead author Catharine W. Burt, Ed.D., with the CDC’s National Center for Health Statistics in Hyattsville, Maryland.
In addition, the CDC study found emergency patients transported to emergency departments by ambulance had serious medical conditions or injuries that required more hospital resources. Nearly 70 percent had medical conditions that were classified as either emergent (needing care in less than 15 minutes) or urgent (needing care within 15-60 minutes), and more than a third (37 percent) were ultimately admitted to the hospital.
"If the closest hospital to the patient is on diversion, the length of time it takes for that patient to receive definitive treatment is likely prolonged," said Burt. "While this study did not examine health outcomes of patients whose ambulances were diverted, it is possible their care was affected when you consider every second counts in an emergency."
To examine the impact of hospital closures and hospital characteristics on ambulance diversions, UCLA researchers looked at ambulance diversion hours for hospitals in Los Angeles County over a seven-year period. The study, which was supported by the UCLA Robert Wood Johnson Clinical Scholars Program, found ambulance diversions at Los Angeles County hospitals more than tripled between 1998 and 2004. A possible reason for this trend may be the increasing number of admitted emergency patients awaiting a hospital bed in emergency departments. According to researchers, this practice is called "emergency department boarding," and has been found to be a predictor of ambulance diversion.
CDC researchers report similar findings. In their research, hospital emergency departments were found to be diverting ambulances when they were overcrowded, citing a lack of appropriate inpatient beds (51 percent), a high number of emergency department visits (50 percent) and complexity of emergency department cases (18 percent).
From 1993 to 2003, the number of emergency departments nationwide decreased by 12 percent as the number of emergency visits rose by 26 percent. Similarly in California, the number of hospital emergency departments shrunk by 12 percent between 1990 and 1999 at the same time emergency visits increased by 27 percent. In addition, between 1990 and 1999, nationwide hospitals lost 103,000 staffed inpatient medical/surgical beds and 7,800 ICU beds.
"As a result, fewer beds are available today for admissions from emergency departments, and the health care system no longer has the surge capacity to deal with sudden increases in patients needing care," said Dr. Brent Asplin, the journal’s editor for this study.
According to the CDC research, an ambulance is more likely to be diverted if it is headed toward a large emergency department that has more than 50,000 annual emergency department visits. This group represented 12 percent of the emergency departments studied, but yet accounted for 18 percent of emergency departments that went on diversion, 47 percent of all hours spent in diversion status, and 70 percent of all ambulances diverted to another emergency department.
UCLA researchers also examined the characteristics of hospitals that divert ambulances and similarly found county-operated hospitals spent 150 more hours on diversion, compared with other hospitals. Researchers also noted that the number of diversion hours tracked at one hospital were similar to the number of diversion hours at its neighboring hospitals, which they called "a network effect."
"This suggests when a hospital decides to divert ambulances, nearby hospitals subsequently go on diversion as they become overwhelmed by the increase in incoming ambulance transports," said the UCLA study’s lead author Dr. Benjamin C. Sun.
The findings uncovered in both ambulance diversion studies provide valuable information for policymakers, public health officials and health care providers, according to UCLA and CDC researchers. For example, in Los Angeles County, UCLA researchers said that the increasing number of diversion hours, as well as an increased "network effect" noted during the study period suggests that emergency department capacity to absorb future closures is dwindling.
UCLA researchers also said the lack of association between the number of emergency visits and ambulance diversion hours indicates that emergency department crowding is more likely the result of diminished emergency department and hospital capacity, rather than increased patient demand for emergency medical services. They said this implies that regulators should carefully scrutinize further closures. Researchers added that the Los Angeles County experience likely mirrors what is happening in many other communities across the country and policy implications may be similar.
The CDC’s researchers said their findings should help policymakers in both the hospital industry and public health arenas plan for demographic changes in the population by providing benchmarks to track changes over the next 15 years.
Annals of Emergency Medicine is the peer-reviewed scientific journal for the American College of Emergency Physicians, a national medical society with more than 23,000 members. ACEP is committed to advancing emergency care through continuing education, research, and public education. Headquartered in Dallas, Texas, ACEP has 53 chapters representing each state, as well as Puerto Rico and the District of Columbia. A Government Services Chapter represents emergency physicians employed by military branches and other government agencies.
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