Intraoperative high and low blood pressures are not associated with delirium after cardiac surgery: A retrospective cohort study

Study objective: To evaluate the associations between high and low intraoperative time-weighted average mean arterial pressures before, during and after cardiopulmonary bypass on postoperative delirium. Design: Single center retrospective cohort study. Setting: Operating rooms and postoperative care units. Patients: 11,382 patients, 18 years of age or older who had cardiac surgery requiring cardiopulmonary bypass between January 2017 and December 2020 at the Cleveland Clinic Main Campus. Interventions: All cardiac surgery requiring bypass except procedures requiring deep hypothermic circulatory arrest. Measurements: Post operative delirium was assessed from 12 to 96 h postoperatively, using the Confusion Assessment Method and brief Confusion Assessment Methods. Hypotension and hypertension were defined as time-weighted average mean arterial pressure < 60 and > 80 mmHg. Main results: Postoperative delirium occurred in 678 (6.0 %) of 11,382 patients. Confounder-adjusted associations, using multivariable logistic regression models, between hypotension (time-weighted average mean arterial pressure < 60 mmHg) and hypertension (time-weighted average mean arterial pressure > 80 mmHg) and postoperative delirium were not statistically significant or clinically meaningful before, during, or after the cardiopulmonary bypass. Conclusions: This large single-center cohort analysis found no evidence that exposure to high or low blood pressures during various intraoperative phases of cardiac surgery are associated with postoperative delirium.