An emergency is commonly defined as any condition perceived by the prudent layperson—or someone on his or her behalf—as requiring immediate medical or surgical evaluation and treatment. On the basis of this definition, the American College of Emergency Physicians states that the practice of emergency medicine has the primary mission of evaluating, managing, and providing treatment to these patients with unexpected injury and illness.

So what does an emergency physician (EP) do? He or she routinely provides care and makes medical treatment decisions based on real-time evaluation of a patient’s history; physical findings; and many diagnostic studies, including multiple imaging modalities, laboratory tests, and electrocardiograms. The EP needs an amalgam of skills to treat a wide variety of injuries and illnesses, ranging from the diagnosis of an upper respiratory infection or dermatologic condition to resuscitation and stabilization of the multiple trauma patient. Furthermore, these physicians must be able to practice emergency medicine on patients of all ages. It has been said that EPs are masters and mistresses of negotiation, creativity, and disposition. Clinical emergency medicine may be practiced in emergency departments (EDs), both rural and urban; urgent care clinics; and other settings such as at mass gathering incidents, through emergency medical services (EMS), and in hazardous material and bioterrorism situations.

Emergency medicine serves as the US health care safety net. It provides valuable clinical and administrative services to the health care delivery system, including care for the indigent and others who lack access to health care, and has evolved as the most visible and vital component of a patchwork of health care providers and facilities. EDs have become the routine, and often the only, source of care for many of the uninsured, thereby acting as a critical safety net for our fragmented health care delivery system.

Finally, EDs are the only element of the health care system whose function has been delineated by federal law. Initially authorized in 1986, the Emergency Medical Treatment and Active Labor Act mandates that all EDs provide screening, stabilization, and appropriate transfer to all patients with any medical condition. Emergency medicine is often the last resort for many patients and frequently the access point for competent, comprehensive, and efficient medical care.

An EP faces numerous challenges. The first and most distinctive challenge is that of limited time. Time constraints occur because of the severity and acuity of the illness and also because of the ever-present worry that someone else will need the physician’s attention. The second challenge for the EP is that he or she needs to quickly assess and make therapeutic decisions on the basis of limited information. The EP may also be providing medical control for patients in the prehospital environment. In addition, the EP also will need to determine what care was given prior to arrival and what impact the intervention made. History may be provided from bystanders or EMS providers and given to the physician second hand.

The EP has a different mindset than other specialties. The main concern of the EP is not necessarily the diagnosis, but a process of thinking aimed at ruling in or out serious pathology that is life- or limb-threatening. The classic model of history taking followed by a physical examination and then diagnostic testing must often be compressed and conducted simultaneously when time is of the essence and the patient’s life is threatened.

The evaluation of patients should proceed in a parallel fashion rather than the time-honored serial method. The mindset that patients must be triaged and registered in the waiting room when there are beds available must be abandoned. Patients should be taken straight away to any available room where the physician and nurse assess the patient and get the history while the patient is simultaneously having an intravenous line with blood work drawn and registration occurring in the room. The single intervention of in-room registration can decrease the length of stay of the patient by an average of 15 minutes.

The ED is a unique environment in that hospital EDs are required by federal law to evaluate patients without regard to ability to pay. In 2005, there were an estimated 45–48 million Americans without health insurance. This puts financial strains on both hospitals and physicians. In addition, patients with nonurgent health problems use the ED for a variety of reasons. Studies have found that the majority of patients were not aware of other places to go for their care. When an ED reaches 140% of its capacity, the number of patients leaving without being seen will increase. This leads to patient dissatisfaction and an increased risk of litigation, not to mention the potential that the patient is leaving with a potential life threat that has not been identified.