ASA classification is generally divided into five levels. Grade I is for healthy patients. Grade II mild systemic disease with no functional limitations. Grade III severe systemic disease with some functional limitations. Grade IV severe systemic disease with a lifelong need for uninterrupted treatment tasks. Grade V usual patients who are unlikely to survive within 24 hours regardless of surgery or not. This is the classification of the American Society of Anesthesiologists’ condition assessment, and the “E” or “emergency” should be added to the assessment for emergency surgery. Grade 4 and 5 patients have a greater risk of anesthesia and require adequate and careful preparation before anesthesia.