Preoperative evaluation of the high-risk patient.

The benefits of surgery are usually clear and easy to define. The risk to which a particular patient is subjected during a specific operation, however, is a multifactorial and complex question related to preoperative condition, the complexity of the surgery proposed, and the skill and experience of the surgeon. We have concentrated our discussion only on preoperative evaluation of the patient's condition. By our system of evaluation of preoperative cardiac, pulmonary, carotid artery, nutritional, and general medical status some estimation of the risk of postoperative complication can be formulated. In some of our discussion we reported studies of other investigators, in which the likelihood of postoperative complications was expressed in percentages. An approach derived by study of groups of patients may or may not apply to a particular patient. Although such an approach may not be entirely accurate, it can assist in the estimation of the chance of serious postoperative complications. Obviously the most ideal situation would be to define precisely the risks and benefits of each operative procedure we recommend to a patient. Because this is not possible, we should state the benefits and estimate the risks of surgery preoperatively. We should also delay operation until the patient's preoperative condition is optimal, thereby decreasing the risks of complications. With a systematic preoperative evaluation these goals can be approximated. A critical part of the benefit-to-risk equation is the surgeon's judgment of whether the patient is a good operative risk. This opinion should not be ignored and should be part of any system of preoperative evaluation of risk of postoperative complications.