American Society of Aanesthesiologist (ASA) classification system

• ASA grade I is defined as normal healthy patients, who are non-smokers and with no/minimal alcohol intake.
• ASA grade II is defined as patients with mild systemic disease e.g. well controlled diabetes or hypertension, current smoker, obesity (BMI 30-40), and mild lung disease.
• ASA grade III is defined as patients with severe systemic disease e.g. poorly controlled diabetes or hypertension, COPD, morbid obesity (BMI >40), history of ACS/stroke/TIA >3 months ago.
• ASA grade IV is defined as patients with severe systemic disease that is a constant threat to life e.g. MI/stroke/TIA within 3 months, severe valve dysfunction, severe reduction in ejection fraction, sepsis.
• ASA grade V is defined as moribund patients not expected to survive the operation e.g. ruptured abdominal aortic aneurysm, massive bleed, intracranial haemorrhage with mass effect.
• ASA grade VI is defined as a patient declared brain-dead whose organs are being removed for donation.