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Dynamic cerebral autoregulation: A marker of post-operative delirium?

Juliana R Caldas1, Ronney B Panerai2, Edson Bor-Seng-Shu3

  • 1Department of Anesthesia, University of Sao Paulo, Brazil; Department of Neurosurgery, Hospital das Clinicas, University of São Paulo, Brazil; Critical Care Unit Hospital São Rafael Salvador, Brazil.

Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology
|December 4, 2018
PubMed

Insights

Cerebral autoregulation (CA) was impaired after cardiac surgery, becoming a significant risk factor for postoperative delirium (PD). Early CA assessment can identify at-risk patients, potentially reducing complications and hospital stays.

Area of Science:

  • Neurology
  • Cardiovascular Surgery
  • Critical Care Medicine

Background:

  • Postoperative delirium (PD) is a common and serious complication following cardiac surgery with cardiopulmonary bypass (CPB).
  • Cerebral autoregulation (CA), the maintenance of stable cerebral blood flow despite blood pressure fluctuations, is crucial for brain function.

Purpose of the Study:

  • To investigate the association between cerebral autoregulation (CA) and the occurrence of postoperative delirium (PD) in patients undergoing coronary artery bypass graft (CABG) surgery with CPB.
  • To identify CA as a potential independent risk factor for PD.

Main Methods:

  • Continuous recording of cerebral blood flow velocity (CBFV) and blood pressure (BP) in 67 patients undergoing CABG with CPB.
  • Calculation of the autoregulation index (ARI) using transfer function analysis to assess CA at three time points: preoperatively, 24 hours postoperatively, and 7 days postoperatively.
  • Prospective multivariate logistic regression analysis to determine independent risk factors for PD.

Main Results:

  • Cerebral autoregulation (CA) was significantly depressed 24 hours after surgery (ARI: 3.9 ± 1.7) compared to preoperatively (ARI: 5.6 ± 1.7) and 7 days postoperatively (ARI: 5.5 ± 1.8).
  • Impaired CA was observed in 55% of patients at 24 hours and 20% at 7 days postoperatively.
  • Lower autoregulation index (ARI) values preoperatively and 24 hours postoperatively were significant predictors of PD (p=0.003).

Conclusions:

  • Dynamic cerebral autoregulation (CA) is impaired following CABG surgery with CPB.
  • Impaired CA is a significant and independent risk factor for the development of postoperative delirium (PD).
  • Assessing CA before and after surgery may aid in the early identification of patients at risk for PD, potentially improving outcomes and reducing hospital length of stay.
Abstract

Keywords:
Cardiac surgeryCardiopulmonary bypassCerebral blood flowLeft ventricular ejection fraction

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