American Society of Anesthesiologists (ASA) Physical Status Classification (Expanded):

• ASA I: Normal healthy patient with no systemic disease.
  Examples: Non-smoker, no alcohol or minimal use, BMI <25, normal blood pressure (<120/80), no medications, excellent functional capacity.

• ASA II: Patient with mild systemic disease without significant functional limitation.
  Examples: Controlled hypertension (e.g., BP <140/90 on medication), well-controlled type 2 diabetes (HbA1c ~6–7%), mild obesity (BMI 30–34.9), pregnancy, social alcohol use, current smoker without COPD, mild asthma, or mild OSA not requiring CPAP.

• ASA III: Patient with severe systemic disease with substantive functional limitations.
  Examples: Poorly controlled hypertension (BP ≥160/100), diabetes with HbA1c >8% or with complications (neuropathy), morbid obesity (BMI ≥40), chronic obstructive pulmonary disease (COPD), obstructive sleep apnea requiring CPAP/NIV, chronic kidney disease stage 3+, history of MI >3 months ago, chronic anticoagulation (e.g., atrial fibrillation on warfarin/DOAC), significant anemia, or active tobacco use with end-organ impact.

• ASA IV: Patient with severe systemic disease that is a constant threat to life.
  Examples: Recent MI (<3 months), unstable angina, decompensated heart failure (EF <30%), severe COPD with frequent exacerbations or oxygen dependence, advanced renal failure requiring dialysis, uncontrolled diabetes with end-organ damage, sepsis, or severe valvular disease.  

• ASA V: Moribund patient not expected to survive without the operation.
  Examples: Ruptured abdominal aortic aneurysm, massive trauma, intracranial hemorrhage with mass effect, ischemic bowel with hemodynamic instability.

• ASA VI: Brain-dead patient whose organs are being removed for donor purposes.

Modifier:

• “E” (Emergency): Added to any classification when immediate intervention is required (e.g., ASA III-E, ASA IV-E), indicating increased perioperative risk due to urgency and limited optimization time.