Intraoperative and postoperative complications in high-risk surgical patients generate prolonged recovery periods and threaten the postoperative survival of patients, and are a reason for admission to the intensive care unit.

All preoperative and postoperative evaluations aimed at mitigating risks are essential for patient care; each year, an estimated 230 million patients worldwide undergo surgical procedures; and although less than 15% of these procedures were performed on high-risk patients, these patients represent 80% of deaths related to complications of high-risk surgeries.

The risk of death and severe complications in these patients after major high-risk surgery is mainly related to their preoperative physiological condition and, in general, their cardiovascular and respiratory reserve, as well as to the type and extent of the surgical procedure.

The term high risk refers to a patient who is clinically considered to be at high risk of peri- and postoperative death. These patients should receive an evaluation for adequate clinical and hemodynamic optimization.

High-risk patients are considered to be those with a clinical history of age >70 years with limited physiological reserve in one or more vital organs; previous myocardial infarction, chronic bronchitis, emphysema (COPD, chronic obstructive pulmonary disease), vascular disease affecting the aorta, extensive surgery (for example, removal of the esophagus, stomach or bladder for problems associated with cancer), abdominal catastrophes (for example, perforated diverticula, pancreatitis), significant blood loss during the procedure, systemic infection (septicemia), patients with respiratory or renal failure before the procedure and patients with intracranial tumors.

Patients with an individual risk of death >5% or who will undergo a procedure with a mortality risk >5% are defined as high surgical risk patients, and those with a probability >20% should be considered extremely high-risk patients.

The care related to the surgery of these patients begins with the interview in the pre-surgical clinical and physiological evaluation consultation, as well as pre-anesthetic and continues in the post-surgical period, in the intensive care unit, by the multidisciplinary medical team, supported by the technological team for diagnosis and expedited treatment, which are combined in the post-surgical intensive care unit and influence the final outcome of the success of the surgery in high-risk patients.