American Society of Anesthesiologists' (ASA) grades

 

The American Society of Anesthesiologists' (ASA) grades⁵

Grade	Status	Absolute Mortality (%)
I	A normal healthy patient. The process for which the operation is being performed is localised and causes no systemic upset.	0.1
II	Mild systemic disease. All patients older than 80 years are put in this category.	0.2
III	Severe systemic disease. This from any cause that imposes a definite functional limitation on their activity e.g. chronic obstructive pulmonary disease.	1.8
IV	Incapacitating systemic disease which is a constant threat to life.	7.8
V	A moribund patient unlikely to survive 24 hours with or without surgery.	9.4

 

 

When the anaesthetic assessment is complete, the anaesthetist will grade the patient according to his or her physiological reserve and the attendant risk from both anaesthesia and surgery (the other thing that upsets the patient's physiology). The most common scoring system in use was devised by the American Society of Anesthesiologists (ASA) (see box 1).

Box 1: ASA physical status classification

ASA I Healthy patient
ASA II Mild systemic disease with no functional limitation - for example, controlled hypertension
ASA III Severe systemic disease with definite functional limitation - for example, chronic obstructive pulmonary disease
ASA IV Severe systemic disease that is a constant threat to life - for example, unstable angina
ASA V Moribund patient who is not expected to survive for 24 hours with or without surgery - for example, with an abdominal aortic aneurysm
Suffix E Emergency procedure

 

The ASA grade has been shown to be a gross predictor of overall perioperative outcome. A patient of ASA I is your friend, on whom you don't inflict any tortures of preoperative investigations. If your patient falls into any of the other categories you must think of how his or her general health may be improved. If it can be improved this will increase the patient's physiological reserve and make him or her less at risk of serious harm. This is an indication for postponing surgery. The time taken for improvement may be anything from a few hours (intravenous fluids for someone about to undergo laparotomy) to several months (weight loss in the morbidly obese patient). At the end of this "physiology improvement period" the patient is reassessed and if the desired improvement has been achieved the operation can go ahead.