Relative cerebral hyperperfusion during cardiopulmonary bypass is associated with risk for postoperative delirium: a cross-sectional cohort study

Marcus Thudium,Richard K Ellerkmann,Tobias Hilbert,Ingo Heinze

doi:10.1186/s12871-019-0705-y

Marcus Thudium, Richard K Ellerkmann + Show 2 more

Open Access

https://doi.org/10.1186/s12871-019-0705-y

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Journal: BMC Anesthesiology	Publication Date: Mar 9, 2019
Citations: 21	License type: open-access

Affiliation: Klinikum Dortmund, University Hospital Bonn

Abstract

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.

Highlights

Our 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
POD is usually supposed to be associated with intraoperative periods of hypotension, there is some evidence suggesting the significance of sustained cerebral hyperperfusion during cardiopulmonary bypass (CPB) [3]
Hori et al demonstrated the association of an arterial blood pressure above the upper limit of cerebral autoregulation with POD, suggesting cerebral hyperperfusion to be present in these patients [4]

Summary

Introduction

Our 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. Postoperative delirium (POD) is one major complication following cardiac surgery. It is known to increase length of intensive care unit (ICU) and hospital stay and postoperative mortality, representing a significant problem for the health care system [1]. POD is usually supposed to be associated with intraoperative periods of hypotension, there is some evidence suggesting the significance of sustained cerebral hyperperfusion during cardiopulmonary bypass (CPB) [3]. Hori et al demonstrated the association of an arterial blood pressure above the upper limit of cerebral autoregulation with POD, suggesting cerebral hyperperfusion to be present in these patients [4]

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