• Marcus Thudium, Richard K Ellerkmann, Ingo Heinze, and Tobias Hilbert.
• Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Sigmund-Freud-Strasse 25, 53127, Bonn, Germany.
• BMC Anesthesiol. 2019 Mar 9; 19 (1): 35.

BackgroundOur objective was to evaluate if changes in on-pump cerebral blood flow, relative to the pre-bypass baseline, are associated with the risk for postoperative delirium (POD) following cardiac surgery.MethodsIn 47 consecutive adult patients, right middle cerebral artery blood flow velocity (MCAV) was assessed using transcranial Doppler sonography. Individual values, measured during cardiopulmonary bypass (CPB), were normalized to the pre-bypass baseline value and termed MCAVrel. An MCAVrel > 100% was defined as cerebral hyperperfusion. Prevalence of POD was assessed using the Confusion Assessment Method for the Intensive Care Unit.ResultsOverall prevalence of POD was 27%. In the subgroup without POD, 32% of patients had experienced relative cerebral hyperperfusion during CPB, compared to 67% in the subgroup with POD (p < 0.05). The mean averaged MCAVrel was 90 (±21) % in the no-POD group vs. 112 (±32) % in the POD group (p < 0.05), and patients developing delirium experienced cerebral hyperperfusion during CPB for about 39 (±35) min, compared to 6 (±11) min in the group without POD (p < 0.001). In a subcohort with pre-bypass baseline MCAV (MCAVbas) below the median MCAVbas of the whole cohort, prevalence of POD was 17% when MCAVrel during CPB was kept below 100%, but increased to 53% when these patients actually experienced relative cerebral hyperperfusion.ConclusionsOur results suggest a critical role for cerebral hyperperfusion in the pathogenesis of POD following on-pump open-heart surgery, recommending a more individualized hemodynamic management, especially in the population at risk.

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