The need for large clinical studies in perioperative medicine.

I N recent decades, substantial advances in surgery have improved disease treatment and patients’ quality of life. Consequently, increasing numbers of patients are having surgery. A recent study that used surgical data from 56 countries suggests that more than 230 million major surgical procedures are undertaken annually around the world. Despite its benefits, surgery is associated with major complications. For example, worldwide approximately 5 million adults annually suffer a major perioperative vascular complication (i.e., vascular death, nonfatal myocardial infarction, nonfatal cardiac arrest, and nonfatal stroke) in the first 30 days after noncardiac surgery. This incidence, remarkably, is similar to the annual global incidence of new cases of human immunodeficiency virus. Despite the magnitude of the problem, there is not a single established effective and safe intervention to prevent major vascular complications after noncardiac surgery. Furthermore, our ability to predict these events is limited. Other complications (e.g., respiratory) are also common and cause substantial morbidity and mortality.