Postoperative pulmonary complications (PPC) are among the main complications after the anesthetic-surgical procedure. It can be said that thoracic surgery results in impaired respiratory function in the postoperatively, due to the decrease in lung volumes and capacities (the vital capacity decreases by approximately 50-60% and functional residual capacity decreases by approximately 30% in the first 24 hours after surgery) diaphragm dysfunction, gas exchange impaired, cough and ineffective mucociliary clearance. Thus, our hypothesis is that the application of preoperative risk scores normally used for non-cardiac and non-thoracic surgeries may be effective on the predictability of the occurrence of CPP in patients undergoing ventilation single-lung. This is a prospective observational study in order to evaluate the performance of the ASA, ARISCAT and LAS VEGAS risk scores for predict the occurrence of postoperative pulmonary complications (PPC) in patients undergoing thoracic surgery with single-lung ventilation.

Postoperative pulmonary complications (PPC) are among the main complications after the anesthetic-surgical procedure; CPP prolong hospital stay and increase costs in health systems. It can be said that thoracic surgery results in impaired respiratory function in the postoperatively, due to the decrease in lung volumes and capacities (the vital capacity decreases by approximately 50-60% and functional residual capacity decreases by approximately 30% in the first 24 hours after surgery) diaphragm dysfunction, gas exchange impaired, cough and ineffective mucociliary clearance.

Thus, our hypothesis is that the application of preoperative risk scores normally used for non-cardiac and non-thoracic surgeries may be effective in the predictability of the occurrence of CPP in patients undergoing ventilation single-lung. In this study, we will prospectively evaluate the performance of ASA, ARISCAT and LAS VEGAS scores in predicting patients who present with CPP in thoracic surgeries using single-lung ventilation. We will also analyze other potential patient risk factors as well as complications presented.

This is a prospective observational study. Data will be collected using a standardized form at the surgical center of Hospital Nossa Senhora da Conceição and at the Hospital de Clínicas de Porto Alegre, evaluated preoperatively, intraoperatively and postoperatively. Direct observation and recording of variables studied by the anesthesiology medical team of both hospitals, previously trained and supervised by the main researcher. Patients will be monitored until hospital discharge or up to a maximum period of 30 days of hospital admission.

Inclusion Criteria:

• Adult patients undergoing any thoracic procedure associated with intraoperative single-lung ventilation.

Exclusion Criteria:

• Patients undergoing cardiac surgery, pregnant women, patient refusal, contraindications to proposed surgical, anesthetic or analgesic techniques, sepsis, psychiatric illness, uncontrolled endocrine, kidney or liver disease and coagulopathies.

Adult patients undergoing any thoracic procedure associated with intraoperative use of single-lung ventilation.