Emergency department

An emergency department (ED) is a specialized medical facility designed for acute care. It focuses on emergency medicine, which treats patients who arrive without a prior appointment.

Patients reach these departments by their own means or via an ambulance. Because attendance is unplanned, the ED must handle a broad spectrum of illnesses and injuries. Some conditions are life-threatening and require immediate medical attention. In many countries, these departments serve as vital entry points for people lacking other medical access. Most EDs operate 24 hours a day, though staffing levels may change based on patient volume.

To manage the unpredictable flow of patients, the ED uses a process called triage. Triage is the first stage of care where staff prioritize cases based on clinical need. A triage nurse or other professional conducts a brief assessment of the patient. This includes checking vital signs and identifying the "chief complaint." A chief complaint is the primary reason the person is seeking help, such as chest pain or difficulty breathing.

Triage can happen face-to-face or via radio with an ambulance crew. While most patients move from triage to another area, some minor cases may be treated and finished right at the triage stage.

Patients are sorted into specific areas based on the severity of their condition. The most critical patients go to the resuscitation area, often called "Trauma" or "Resus." This area contains the specialized equipment and staff needed for life-threatening emergencies.

Typical resuscitation teams include at least one attending physician and one or two nurses trained in Advanced Cardiac Life Support. Other specialists, like respiratory therapists or pharmacists, may join the team depending on the case. Patients who are seriously ill but not in immediate danger move to "acute care" or "majors." In this area, doctors perform thorough assessments and advanced diagnostic testing. This testing might include blood work, ultrasonography, CT scans, or MRI scans.

Patients with non-life-threatening issues are directed to "minors" or "prompt care" areas. These areas handle conditions like fractures, dislocations, or lacerations that require suturing. Some hospitals also include specialized sections for specific needs. For example, pediatric areas serve children, sometimes employing play therapists to reduce anxiety.

Other hospitals maintain separate areas for psychiatric evaluations. These sections are often staffed by psychiatrists, mental health nurses, and social workers. They may include specific rooms for individuals who pose a risk to themselves or others.

The history of specialized emergency care shows how much medical systems have evolved. By the late mid-nineteenth century, accident services were provided by municipalities and railway companies in the United States and Europe. However, the world's first specialized trauma care center opened in 1911. This facility was located at the University of Louisville Hospital in Louisville, Kentucky. In the 1930s, surgeon Arnold Griswold further developed these services. He equipped police and fire vehicles with medical supplies and trained officers to provide emergency care during transport.

Emergency departments are massive operations with significant statistical footprints. In the United States, the Centers for Medicare and Medicaid Services classifies them into two types. Type A departments are open 24 hours a day, 365 days a year. Type B departments are not. In 2009, there were an estimated 128,885,040 ED encounters in U.S. hospitals. During the 2009–2010 period, 19.6 million of those visits were made by people aged 65 and older. Data from 2010 shows that about one-fifth of all ED visits involved patients under the age of 18. In most cases, 82.8 percent of encounters result in treatment and release, while 17.2 percent lead to inpatient admission.

Different regions use different names and signage for these facilities. In the United Kingdom and Hong Kong, the term "Accident and Emergency" (A&E) is common. In North America, people often use "emergency room" or "ER."

Directional signs often feature white text on a red background to help people find help quickly. In the United States, the 1986 Emergency Medical Treatment and Active Labor Act requires hospitals receiving Medicare payments to treat everyone. This applies regardless of a person's citizenship, legal status, or ability to pay. This law ensures that the emergency department remains a critical safety net for the entire community.