Postoperative delirium affects up to 60% of cardiac surgical patients. No reliable gold standard method exists for preventing delirium after cardiac surgery. An example of patient-personal monitoring is cerebral autoregulation (CA). This study aims to highlight the personal monitoring of patients’ cerebral autoregulation and to determine its relationship with postoperative delirium. Additionally, it seeks to test the hypothesis that the duration of CA impairment influences the onset of postoperative delirium.

A prospective study was conducted in 2021–2023. After approval of the Ethics Committee and with the patient’s written consent, 104 adult patients undergoing elective coronary artery bypass graft (CABG) with cardiopulmonary bypass (CPB) surgery were enrolled. To diagnose possible delirium, all patients underwent a Confusion Assessment Method for the Intensive Care Unit (CAM–ICU) test. CA monitoring using transcranial Doppler was performed. CA status index – Mx was recorded.

Our study found that 12.5% of patients were diagnosed with delirium after on-pump CABG surgery. The total duration of cerebral autoregulation impairment (TCAI) was longer in the delirium group, 4783.0 seconds versus 4204.5 seconds (p = .047), with a cut-off at 4380 s. Longer cardiopulmonary bypass (CPB) leads to prolonged CA impairment (p < .001). The mean arterial pressure (MAP) during CPB was 69.67 mmHg in the non-delirium group and 74.91 mmHg in the delirium group (p = .001), with a cutoff at 73.669 mmHg.

CA impairment is crucial for delirium development after cardiac surgery. The duration of the TCAI event increases the risk of delirium.