Introduction: The causes of delayed recovery of consciousness from anesthesia after cardiac surgery with cardiopulmonary bypass are diverse and often related to multiple factors. This study investigated the factors affecting the time to recovery of consciousness in patients undergoing cardiac surgery with cardiopulmonary bypass at our hospital.

Methods: The retrospective observational study included 113 patients aged ≥20 years who underwent cardiac surgery with cardiopulmonary bypass at Tokyo Medical University Hachioji Medical Center between January 2019 and December 2022. Patients who underwent cardiovascular surgery with selective cerebral perfusion, patients who underwent cardiac surgery without cardiopulmonary bypass, patients with preoperative impaired consciousness, patients who used sedatives preoperatively, patients with postoperative cerebrovascular complications, patients who refused to consent to participate in the study, and patients whose information necessary for the study was not recorded were excluded. Preoperative and intraoperative variables that could affect the time to recovery of consciousness were selected for statistical analysis. Univariate and multivariate linear regression analyses were performed to assess the association of these factors with time to recovery of consciousness.

Results: Univariate linear regression analysis revealed that albumin, estimated glomerular filtration rate (eGFR), and bicaudate ratio (BCR) were significantly associated with the time to recovery of consciousness. In the multivariate linear regression analysis, eGFR and BCR had significant associations. The regression coefficients were negative for eGFR and positive for BCR. The reduced model obtained through the backward step-down methods showed an improved fit and included these significant variables and other factors.

Conclusions: Preoperative renal dysfunction and brain atrophy were identified as factors affecting the postoperative time to recovery of consciousness after cardiac surgery with cardiopulmonary bypass. Additionally, cardiopulmonary bypass time and hypoalbuminemia suggested that they were related to the time to recovery of consciousness. For patients with renal dysfunction, brain atrophy, or hypoalbuminemia, adjusting the dose and timing of anesthetic agent administration during induction and surgery may help reduce the time to recovery of consciousness.