ASA Physical Status Classification System

The ASA physical status classification system is a system for assessing the fitness of patients before surgery. In 1963 the American Society of Anesthesiologists (ASA) adopted the five-category physical status classification system; a sixth category was later added. These are:

1. A normal healthy patient.
2. A patient with mild systemic disease.
3. A patient with severe systemic disease.
4. A patient with severe systemic disease that is a constant threat to life.
5. A moribund patient who is not expected to survive without the operation.
6. A declared brain-dead patient whose organs are being removed for donor purposes.

If the surgery is an emergency, the physical status classification is followed by “E” (for emergency) for example “3E”. Class 5 is usually an emergency and is therefore usually "5E". The class "6E" does not exist and is simply recorded as class "6", as all organ retrieval in brain-dead patients is done urgently. The original definition of emergency in 1940, when ASA classification was first designed, was "a surgical procedure which, in the surgeon's opinion, should be performed without delay." This gives an opportunity for a surgeon to manipulate the schedule of elective surgery cases for personal convenience. An emergency is therefore now defined as existing when delay in treatment would significantly increase the threat to the patient's life or body part. With this definition, severe pain due to broken bones, ureteric stone or parturition (giving birth) is not an emergency.