As an emergency room doctor, you never know what's coming through that door. It could be someone with stab wounds, a baby in distress, bus accident victims or an elderly man with pneumonia.

"The best part about being a doctor for emergency department is that moment when you know you've changed someone's life positively. Sometimes, it's something small, not what most people think of as life-saving, but it's lifesaving to that person," says Xu Jin.

Xu Jin has been an emergency room doctor since July 2005, and now he serves as the attending doctor in the emergency department at Peking Union Medical College Hospital.

"We take care of patients of every age from the moment of birth to grandmas and grandpas in their 90s," he says. "There is no type of injury, medical, surgical, obstetrical, psychiatric or pediatric condition that we aren't equipped to care for."

Today's emergency department looks after so much more than other departments that some people have started calling us, the "everything department", Xu says.

"We care for everything. Regardless of what brings a patient to the emergency department, it's my job to look after them," he says.