Comparison of cerebral metabolic rate of oxygen, blood flow, and bispectral index under general anesthesia

Abstract

Cerebral blood flow; Diffuse optics; Propofol-induced anesthesia

Flujo sanguíneo cerebral; Óptica difusa; Anestesia inducida por propofol

Flux sanguini cerebral; Òptica difusa; Anestèsia induïda per propofol

Significance The optical measurement of cerebral oxygen metabolism was evaluated. Aim Compare optically derived cerebral signals to the electroencephalographic bispectral index (BIS) sensors to monitor propofol-induced anesthesia during surgery. Approach Relative cerebral metabolic rate of oxygen (rCMRO2) and blood flow (rCBF) were measured by time-resolved and diffuse correlation spectroscopies. Changes were tested against the relative BIS (rBIS) ones. The synchronism in the changes was also assessed by the R-Pearson correlation. Results In 23 measurements, optically derived signals showed significant changes in agreement with rBIS: during propofol induction, rBIS decreased by 67% [interquartile ranges (IQR) 62% to 71%], rCMRO2 by 33% (IQR 18% to 46%), and rCBF by 28% (IQR 10% to 37%). During recovery, a significant increase was observed for rBIS (48%, IQR 38% to 55%), rCMRO2 (29%, IQR 17% to 39%), and rCBF (30%, IQR 10% to 44%). The significance and direction of the changes subject-by-subject were tested: the coupling between the rBIS, rCMRO2, and rCBF was witnessed in the majority of the cases (14/18 and 12/18 for rCBF and 19/21 and 13/18 for rCMRO2 in the initial and final part, respectively). These changes were also correlated in time (R > 0.69 to R = 1, p-values < 0.05). Conclusions Optics can reliably monitor rCMRO2 in such conditions.

This work received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 675332 (BitMap), No. 101016087 (VASCOVID) and No. 101017113 (TinyBRAINS), KidsBrainIT (ERA-NET NEURON), FEDER EC and LASERLAB-EUROPE V (EC H2020 no. 871124). It was also supported by Fundació CELLEX Barcelona, Fundació Mir-Puig the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2015-0522), the Obra social “la Caixa” Foundation (LlumMedBcn), Generalitat de Catalunya (CERCA, AGAUR-2017-SGR-1380, RIS3CAT-001-P-001682 CECH), la Fundació La Marató de TV3 (201724.31 and 201709.31), and by Agencia Estatal de Investigación (PHOTOMETABO, PID2019-106481RB-C31/10.13039/501100011033).