ED overcrowding and ambulance diversion cause potential liabilities

By Jay Weaver, MD, EMT-P, Attorney, Private Practice, Paramedic, Boston Public Health Commission, Boston, MA

Emergency medicine practitioners have little control over the flow of patients into their facilities. Federal law requires them to examine and treat virtually everyone who comes through the door. Traditionally, ED directors have eased congestion by diverting ambulances to other hospitals. Now, though, with hospitals everywhere filling to capacity, this practice may create more problems than it solves.

Emergency physicians who provide medical oversight to EMS agencies have a duty to manage ambulance diversion responsibly. So, too, do physicians and nurses who have the authority to order ambulance diversion on behalf of the facilities in which they work. In fact, all ED practitioners should know something about ambulance diversion because of the profound logistical and economic implications it can have on their hospitals. To make sense of this practice, however, one must first understand why it is used.

ED Overcrowding: The Basis for Ambulance Diversion

ED utilization has increased steadily in recent years. Between 1958 and 2000, the number of ED visits grew by approximately 600%.1 During the past decade alone, ED visits have increased by 26%. Today, more than 114 million Americans seek care at these facilities annually.2 This has caused 90% of the EDs at large hospitals and level I trauma centers to operate at or above capacity.3

It would be easy to blame this phenomenon on the excessive, inappropriate use of EDs by patients who don't require emergency treatment. While it is true that the poor and uninsured have increasingly turned to EDs for routine medical care, this is not the principal cause of ED overcrowding.4 Rather, ED overcrowding is primarily a byproduct of hospital overcrowding, representing a backup of seriously ill patients who cannot be admitted due to a shortage of inpatient beds.5 To compensate for reductions in Medicare and Medicaid reimbursement, hospitals eliminated nearly 40% of all inpatient beds between 1981 and 1999. With the remaining beds filled almost constantly, ED practitioners have found it increasingly difficult to admit patients requiring unscheduled care.6 At hospitals with overcrowded EDs, the average wait for admission now exceeds five hours.7

Adding to this problem is the fact that fewer EDs now exist. Between 1993 and 2003, one out of every eight EDs closed as hospitals merged in an effort to contain costs.2 Obviously, this leaves more patients for each remaining ED to treat.

Faced with unprecedented numbers of patients, and no place to send them after they've been stabilized, some EDs have resorted to the practice of "boarding" admitted patients in the ED—sometimes for days. This is not an ideal solution, of course. Boarding ties up staff and ED beds, slowing the rate at which patients may be processed, and thereby delaying the examination and treatment of subsequently arriving patients. This adds to the burden of already-overworked ED personnel, increasing the likelihood of diagnostic and treatment errors, and delaying some patients from receiving specialized treatment available only in a critical care unit.8

The American College of Emergency Physicians (ACEP) has defined ED overcrowding as "a situation in which the identified need for emergency services outstrips available resources in the ED."9 This has proven an elusive concept to measure. Some authorities consider an ED to be overcrowded when the waiting time to see a physician becomes excessive. Others look at patterns of movement from ED to inpatient beds, or the relationship between patient acuity and staffing. Indeed, in some studies, ambulance diversion itself has been used as a measure of ED overcrowding.4

By any standard, the nation's EDs are now overwhelmed. A decade ago, only one ED director in ten expressed concern about overcrowding. Today, nearly all ED directors consider it a serious problem. More than half report that their EDs are overcrowded several times each week, while 39% report that this happens daily. Even more troubling is the fact that one-third of the respondents have witnessed poor patient outcomes directly linked to overcrowding.10

The Emergency Medical Treatment and Active Labor Act (EMTALA) requires EDs to provide screening examinations and stabilizing care to all who present with an emergent condition.11 This makes it illegal for ED personnel to turn patients away once they have arrived at the hospital. To cope with overcrowding, doctors and nurses must act sooner, turning patients away before they get to the ED. Ambulance diversion represents one of the few ways to accomplish this legally.

The Nature of Ambulance Diversion

Ambulance diversion refers to the rerouting of incoming ambulance traffic by a hospital that cannot handle additional patients. In some parts of the country, this has become an "all or nothing" proposition, with hospitals either "open" or "closed" to ambulances. Others make a distinction between hospitals that would prefer not to accept additional emergency patients and those that have been completely overwhelmed. Similarly, some regulatory authorities allow hospitals to declare themselves "closed" due to a lack of inpatient beds, while others allow hospitals to divert ambulances only when their EDs become full.

This is not a new concept. A quarter-century ago, in a story about Long Island's packed EDs, a New York Times reporter wrote that "hospitals often ask ambulance drivers, by means of two-way radios used to alert emergency rooms to imminent arrivals, to go elsewhere."12 For many years, diversion occurred only in urban areas during winter influenza outbreaks.4 But as ED overcrowding has exploded into a nationwide, year-round phenomenon, smaller hospitals—including those in rural areas—have been forced to divert ambulances as well.

Diversions now occur more than half a million times each year, or roughly once every minute.2 A study of Washington hospitals revealed that EDs typically close to ambulance traffic 18 times each month for an average of 7.5 hours per day.9 In major American cities, where ED overcrowding remains most prevalent, hospitals remain on divert status as much as half of the time.3

Of the 16 million patients transported by ambulances to EDs each year, 70% are triaged as emergent or urgent, meaning that they require treatment within one hour.5 These people need to receive care in a hospital, not in an ambulance. Diversion adds to transport time, thereby delaying the onset of care. This becomes a critical consideration when the patient suffers from myocardial infarction, stroke, respiratory failure, or other conditions requiring immediate intervention. According to one Congressional study, ambulance diversion now impedes timely access to emergency care in the metropolitan areas of 22 states, affecting 75 million Americans.13

Diversion also impedes access to emergency medical services (EMS). Long-distance transports occupy ambulances and their crews for prolonged periods of time, leaving them unavailable for subsequent emergencies. This exposes the public to delayed emergency responses, thereby placing the entire community at risk.14

Since overcrowding rarely exists at just one hospital, ambulance diversion by one ED may cause surrounding EDs to overflow, forcing them to divert ambulances, as well. Simultaneous diversion by multiple hospitals in contiguous areas poses an especially serious problem, because it leaves ambulances with no destination at all. When this happens, EMS authorities may refuse to honor diversion requests, or public health authorities may order rotating diversion.4 Such was the case in Phoenix, Arizona, several years ago, when EMS had to override diversion requests virtually every day for an entire month—an experience that prompted one physician to conclude that "the concept of ambulance diversion decompression is failing."15

For a while, ambulance diversion served a useful purpose. By halting the flow of seriously ill patients, it gave ED personnel an opportunity to admit some patients and discharge others, thereby clearing hospitals of gridlock. But now there are just too many patients, and not enough places to treat them. Diverting ambulances at will is no longer a suitable option.

Diverting Ambulances Responsibly

In today's competitive healthcare environment, ED practitioners and administrators sometimes succumb to pressure to divert ambulances as a cost containment measure, ensuring that inpatient beds will remain open for high-paying elective surgery candidates. To do so constitutes a grave mistake. Such practices are illegal under EMTALA, and carry a penalty of $50,000 and possible exclusion from the Medicare and Medicaid reimbursement programs—plus a risk of civil liability.

The Centers for Medicare and Medicaid Services (CMS) has stated in its Interpretive Guidelines that "[a] hospital may divert individuals when it is in 'diversionary' status because it does not have the staff or facilities to accept any additional emergency patients at that time."16 No other EMTALA provision permits a hospital to deny emergency care to any patient. Thus, a hospital may not rely on a shortage of inpatient beds to justify diversion. Only after the ED's resources have been exhausted may a hospital turn away ambulances.

When care begins. These guidelines go on to say that "if any ambulance disregards the hospital's instructions and brings the individual on to hospital campus, the individual has come to the hospital and the hospital has incurred an obligation to conduct a medical screening examination for the individual."16 Moreover, CMS has informed hospitals that an EMTALA obligation arises when the patient arrives in the emergency department, not when care is "accepted" by hospital personnel from EMS personnel.17 It should be clear from these statements that a hospital does not enjoy an absolute right to divert incoming ambulances. Rather, diversionary status amounts to a request—a request that may be honored or ignored by area EMS agencies and ambulance companies.

A Hawaii physician learned this lesson the hard way. In Arrington v. Wong, the Ninth Circuit Court of Appeals held that he may have violated EMTALA by turning away an ambulance by radio when his hospital was not on diversionary status. The court went on to suggest that he would have had an obligation to accept the patient even if his hospital had been on diversionary status if the EMTs had ignored the diversion and continued to his hospital.18

Patient choice. To some extent, then, patient autonomy trumps a hospital's diversionary status. A patient may demand to be transported to a "closed" ED, and if EMS personnel agree to bring him there, the hospital cannot legally turn him away. The patient should be made to understand, however, that he accepts the risk of delayed care by overriding the diversion. EMS personnel have a legal obligation to provide sufficient details to permit informed consent. Once the patient reaches the ED, hospital staff have a similar duty to provide information about the anticipated waiting period.

Consider area hospital capacity/specialty. Hospital diversion decisions should take into account the capabilities of surrounding hospitals. A community hospital may divert ambulances to other community hospitals, for example, with relatively little impact on patient care. When a regional trauma center closes to ambulance traffic, however, EMS personnel may be left with no alternative destination. Specialty centers should, therefore, divert ambulances rarely, if ever. If only for ethical reasons, these facilities should consider adopting a policy that permits diversion of routine ambulance traffic while remaining open to patients requiring specialized care.

It's difficult to say just how badly an ED must be overwhelmed before diversion is justified. Diverting too frequently imposes an unfair burden on surrounding facilities, which may spark a community-wide public health crisis. But waiting too long may cause problems as well. Several years ago, a Maryland hospital effectively refused to close, accepting ambulance traffic regardless of conditions in its ED. The facility soon filled, and EMS personnel had to wait hours with patients until a bed became free. After many such incidents, the county gave paramedics the authority to decide for themselves whether to bypass the hospital since the facility had proven itself unable to perform its public duty.19

Who should have the authority to place a hospital on diversionary status?

Opinions vary. Some hospitals give this authority to the senior on-duty emergency physician. Others give it to an administrator, ED charge nurse, or hospital nursing supervisor. ACEP recommends vesting this authority in an ED physician with the cooperation of the administrative and nursing staff.20 Regardless of position or title, the person who authorizes diversion must have an appreciation of the legal, medical, logistical, and financial implications of such a decision.

When advising EMS agencies, ED practitioners must know when to honor diversion, and when to ignore it. An ambulance service that ignores a hospital's diversionary status may incur liability if a patient suffers harm from a delay in treatment. At the same time, EMS personnel have an obligation to deliver patients to a hospital within a reasonable time. This becomes something that's difficult to accomplish when all area hospitals have closed to ambulance traffic. It is not unreasonable, then, for an EMS agency to adopt a policy under which a specified number of diversions triggers the re-opening of all area EDs. The Metropolitan Boston EMS Council has entered into an agreement with Boston hospitals, for example, that permits no more than two EDs to divert ambulances simultaneously.


ED personnel have long relied on ambulance diversion to reduce overcrowding. With the demand for emergency care rapidly outpacing demand, this practice has become less effective and more problematic. Better methods exist for controlling patient flow—methods that include the use of observation units for short-term admissions, "fast track" facilities for patients requiring little care, and a "bed czar" to coordinate bed utilization throughout the hospital. ED practitioners who persist in diverting ambulances should realize that this may create legal problems, as well as ethical and logistical ones.


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3. The Lewin Group. Emergency Department Overload: A Growing Crisis—The Results of the American Hospital Association Survey of Emergency Department (ED) and Hospital Capacity. Falls Church, VA: American Hospital Association, 2002.

4. American Academy of Pediatrics, Committee on Pediatric Emergency Medicine. Overcrowding crisis in our nation's emergency departments: is our safety net unraveling? Pediatrics 2004;114:878-88.

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8. Gordon JA, Billings J, Asplin BR, et al. Safety net research in emergency medicine: proceedings of the Academic Emergency Medicine Consensus Conference on "The Unraveling Safety Net." Acad Emerg Med 2001;8:1024-9.

9. American College of Emergency Physicians, Crowding Resources Task Force. Responding to Emergency Department Crowding: A Guidebook for Chapters. Dallas, TX: American College of Emergency Physicians; 2002.

10. Derlet R, Richards J, Kravitz J. Frequent overcrowding in U.S. emergency departments. Acad Emerg Med 2001;8:151-5.

11. 42 U.S.C. § 1395dd.

12. "Overcrowding at L.I. Hospitals Assailed," by Frances Cerra. New York (NY) Times, April 30, 1982.

13. Waxman HA. National Preparedness: Ambulance Diversions Impede Access to Emergency Rooms. Washington, DC: US House of Representatives, Committee on Government Reform; 2001.

14. Redelmeier DA, Blair PJ, Collins WE. No place to unload: a preliminary analysis of the prevalence, risk factors, and consequences of ambulance diversion. Ann Emerg Med 1994;23:43-7.

15. Taylor TB. Emergency services crisis of 2000—the Arizona experience. Acad Emerg Med 2001;8:1108-10.

16. US Department of Health and Human Services, Centers for Medicare and Medicaid Services. State Operations Manual, Appendix V, tag 406. Available at: http://www.cms.hhs.gov/Manuals/IOM (accessed July 30, 2007).

17. US Department of health and Human Service, Centers for Medicare and Medicaid Services. EMTALA Issues Related to Emergency Transport Services (memorandum). April 27, 2007.

18. Arrington v. Wong, 237 F.3d 1066 (9th Cir. 2001).

19. Medical Advisory Committee, Pennsylvania Emergency Health Services Council. Joint Position Statement: Guidelines for Ambulance-Diversion Policies. Mechanicsburg, PA: Pennsylvania Emergency Health Services Council, 2004.

20. American College of Emergency Physicians, Emergency Medical Services Committee. Guidelines for Ambulance Diversion. Dallas, TX: American college of Emergency Physicians, 1999.