First person | Xiao Feng

Dr. Xiao Feng, an emergency room physician in the Departments of Emergency Medicine at Beijing United Family Hospital and the Upper Chesapeake Medical Center in Maryland in the US, talks about how the system functions to meet the needs of pre-hospital patients and communities.

Emergency medical services in the US are regulated by federal, state and local governments and organizations. They are operated by a number of different entities, including volunteers, nonprofit organizations and commercial companies. EMS patient care is delivered by ambulance-based first responders, emergency medical technicians and paramedics under the guidance of hospital-based physicians.

EMS in Maryland, one of the best systems in the US, is coordinated by the Maryland Institute for Emergency Medical Services Systems, which provides training, licensing, quality control and the publication of protocols. Two regional emergency medical resources centers act as "communication coordinators" between EMS providers and the medical facilities.

In a case of an emergency, a 911 call will be dispatched to the police, the fire or ambulance services. After initial evaluation and treatment, the providers contact the resources centers, whose staff link the ambulance crew to the closest ER. The centers also coordinate conference calls if wider consultation is required in the event of a major incident.

There are no standard federal or state response times, but usually ambulances arrive within 7 or 8 minutes of being summoned.

US law states that ambulances must have at least two medical workers, but doctors rarely travel in them to avoid wasting resources. Levels of crew certification vary, depending on the jurisdiction in which the ambulance operates.

Charge nurses at ER base stations primarily answer EMR calls through the radio network and prepare the ER for the patient's arrival. They also work with hospital administrators and ER physicians to determine the facility's capacity for safe patient care and report alert levels to the emergency medical resources centers.

A "yellow" alert means the ER is busy and can only accept patients who are unstable or in a life-threatening condition. A "red" alert indicates that the facility has no empty beds with cardiac monitoring equipment.

A "blue" alert, only occurs when the hospital has, in effect, suspended operations and is unable to receive patients because of a critical situation such as a power outage, fire, gas leak or bomb threats.

All alert information is centralized, monitored and displayed in real time through an online County Hospital Alert Tracking System. In the event of an alert, resource center staff immediately notify all ambulances within the affected area.

Patients in a critical condition are taken to the closest hospital, even if they are on red or yellow alerts.

Equipment and procedures are necessarily limited in the pre-hospital environment, and EMS professionals are trained to follow a formal and carefully designed protocol, which helps ensure a consistent approach to the most common types of emergencies.

Xiao Feng talks to Yang Wanli.