Perioperative mortality has been defined as any death, regardless of cause, occurring within 30 days after surgery in or out of the hospital.[1] Globally, 4.2 million people are estimated to die within 30 days of surgery each year.[2] An important consideration in the decision to perform any surgical procedure is to weigh the benefits against the risks. Anesthesiologists and surgeons employ various methods in assessing whether a patient is in optimal condition from a medical standpoint prior to undertaking surgery, and various statistical tools are available. ASA score is the most well known of these.[citation needed]