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.