Which ASA grade would a patient with a urinary obstruction be assigned?

• A. I
• B. II
• C. IV
• D. III

Answer: (C)

ASA classifications gauge preoperative risk based on systemic health. A urinary obstruction is not just a local issue; it can lead to serious systemic problems such as renal impairment, electrolyte disturbances, urosepsis, and quick deterioration of the patient’s condition. When such a potential for life-threatening systemic illness exists, the description fits a severe systemic disease that is a constant threat to life. That is why the appropriate category is the one that denotes this level of risk. If there were no systemic consequences, milder categories would apply, but with a urinary obstruction posing ongoing danger to life, the highest non-terminal risk category is used.