Effects of blood pressure on brain metabolism during cardiopulmonary bypass

Marianne Suwalski; Daniel Milej; Ajay Rajaram; Mamadou Diop; John Murkin; Jason Chui; Keith St. Lawrence

doi:10.1117/12.2649998

14 March 2023 Effects of blood pressure on brain metabolism during cardiopulmonary bypass

Marianne Suwalski, Daniel Milej, Ajay Rajaram, Mamadou Diop, John Murkin, Jason Chui, Keith St. Lawrence

Proceedings Volume 12364, Clinical and Translational Neurophotonics 2023; 123640H (2023) https://doi.org/10.1117/12.2649998
Event: SPIE BiOS, 2023, San Francisco, California, United States

Abstract

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with postoperative neurological complications. Targeted mean arterial blood pressure (MAP) during cardiac surgery is used as one method of maintaining adequate cerebral blood flow (CBF) and perfusion pressure. However, an MAP target of 60 mmHg after transitioning on CPB, which is used in many centers, does not account for the reported broad range of lower autoregulatory limits (50-90 mmHg) [1]. In an effort to maintain cerebral perfusion, near-infrared spectroscopy (NIRS) is used to monitor tissue oxygen saturation (StO₂); however, StO₂ is not a direct marker of CBF or tissue oxygen demand. As an alternative, possible effects on cerebral energy metabolism could be monitored by using hyperspectral NIRS (hsNIRS) to measure changes in the redox state of cytochrome c oxidase (ΔoxCCO), which are linked to ATP production. In this study, an in-house built hsNIRS/diffuse correlation spectroscopy (DCS) was used to monitor ΔoxCCO, CBF and StO₂ in patients during cardiac surgery with CPB. Fourteen patients were retrospectively grouped according to the level of their MAP when transitioning onto CPB: high (70-90 mmHg), target (57-69 mmHg), and low MAP (40-56 mmHg). The aim was to evaluate the potential effects of MAP on ΔoxCCO during the transition onto CPB. Results demonstrated that the smallest changes in oxCCO (-0.08 ± 0.24 μM) were observed in the high MAP group and significantly larger changes (-0.73 ± 0.25 μM) in the low MAP group. The results highlight the potential of ΔoxCCO monitoring for real-time assessment of MAP management during CPB with the ultimate aim of mitigating adverse cerebral events.

Conference Presentation

Citation Download Citation

Marianne Suwalski, Daniel Milej, Ajay Rajaram, Mamadou Diop, John Murkin, Jason Chui, and Keith St. Lawrence "Effects of blood pressure on brain metabolism during cardiopulmonary bypass", Proc. SPIE 12364, Clinical and Translational Neurophotonics 2023, 123640H (14 March 2023); https://doi.org/10.1117/12.2649998

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