Coronary artery bypass graft surgery (CABG) is associated with postoperative respiratory depression. In this study we aimed at investigating perioperative parameters that could predict the nadir of postoperative respiratory function impairment.

Coronary artery bypass graft (CABG) surgery is a principal revascularization option for ischemic heart disease and the principal modality for invasive treatment of coronary artery disease. Postoperative pulmonary complications are the most frequent and significant contributor to length of hospitalization, morbidity and mortality. The objective of this study is to search for perioperative parameters that could predict the degree of impairment of respiratory function after CABG with cardiopulmonary bypass (CPB).

Inclusion Criteria:

• patients of both sexes older than 18 years submitted to CABG with CPB, presence of coronary disease confirmed by coronary angiography, use of the left internal thoracic artery and/or saphena, patients who remained in spontaneous ventilation on the first postoperative day, absence of chronic or acute pulmonary disease, and giving written informed consent to participate in the study.

Exclusion Criteria:

• intraoperative change of the surgical technique, surgical complications or complications occurring in the ICU, emergency reoperation, renal failure, failure to agree to continue in the study, presence of other types of heart disease, and presence of pulmonary diseases.

Patients with coronary artery disease submitted to elective CABG with CPB.