Critical care nurse focuses on the patient who is high dependency, life-threatening diseases, critically ill or unstable patients following surgery and operate/maintain life support systems. Critical care nurse can play their role in different environment and specialities such as cardiovascular intensive care units, intensive care unit, general intensive care units, and coronary care units. They can also work in the intensive care unit, trauma unit, and emergency room by undertaking some course such as trauma care course which is offered by the Emergency Nurse Association. Their duty is assisting the doctor, checking the patient vital sign, managing ventilation and life supporting equipment, taking blood samples and performing diagnostic tests.