1. Identify patients who require medical therapy for a disease or condition before elective surgery (e.g., a 65-year-old patient who has unstable left main coronary artery disease scheduled to undergo a total hip arthroscopy).

2. Identify patients whose medical conditions are so poor that the proposed surgery will hasten their death instead of improving the quality of their lives (e.g., a patient with end-stage kidney failure and myocardial failure who is scheduled for an 8-hour multilevel spinal fusion).

3. Identify patients with specific characteristics that will alter the anesthetic plan (e.g., difficult airway, history of malignant hyperthermia, severe postoperative nausea and vomiting, or postoperative delirium).

4. Provide the patient with an estimate of anesthetic risk.

5. Provide the patient with a description of the anesthetic plan, provide psychological support, answer questions or concerns, and obtain informed consent.

  I. A normal healthy patient.

 II. A patient with mild systemic disease.

III. A patient with severe systemic disease.

 IV. A patient with severe systemic disease that is a constant threat to life.

  V. A moribund patient who is not expected to survive without the operation.

 VI. A declared brain-dead patient whose organs are being removed for donor purposes.

I. Patient who is healthy with no major organic, physiologic, or psychiatric disturbances. This patient would have good exercise tolerance. This patient would not be at either end of the age continuum (very young or old).

II. This patient has no functional limitations and therefore has good exercise tolerance. A well-controlled disease of one organ system may be present such as hypertension, diabetes without complications, cigarette smoking without chronic obstructive pulmonary disease (COPD) or emphysema, mild obesity, or pregnancy.

III. This patient demonstrates some functional limitation. The patient has a controlled disease state of more than one organ system but without imminent concern for death. Patients may have controlled congestive heart failure (CHF), stable angina, a history of myocardial ischemia, poorly controlled hypertension, morbid obesity, chronic renal failure, cigarette smoking with COPD or emphysema, or bronchospastic disease with intermittent symptoms.

IV. This patient has at least one severe disease that is poorly controlled or at the end stage of medical management. This patient has the risk of death with or without surgery. This patient may have unstable angina, symptomatic COPD, symptomatic CHF, or hepatorenal failure.