Noninvasive Electrical Impedance Tomography Monitoring during Total Aortic Arch Replacement: incremental value for prediction of postoperative neurological deficit

Objectives Neurological deficit (ND) following total aortic arch replacement (TAAR) carries high morbidity and mortality, and effective treatments are lacking. Intraoperative neuromonitoring is crucial in preventing ND. This cohort study aims to investigate the prognostic value of noninvasive electrical impedance tomography (EIT) for detecting ND after TAAR. Methods In this study, a 16 electrode EIT system was applied to monitor patients' brain impedance during TAAR. Six EIT parameters regarding to the hypothermic circulatory arrest (HCA) phase were extracted. The correlation between changes in EIT parameters and ND were fully explored. Results The incidence of ND was 39.1% (59/151), of which stroke was 15.2% (19/125). The time integral of absolute value resistivity asymmetric index (TRAI _HCA ), the maximum value of the absolute resistivity asymmetric ratio (MRAR _HCA ), age, body mass index, supra-aortic branch vessel involvement and operation time were independent predictors of ND. The incorporation of EIT parameters into the clinical model resulted in a notable enhancement in area under the receiver operating characteristic curve from 0.752 to 0.817 (P = 0.027). Furthermore, the incremental value of EIT parameters was also reflected in the improvement of risk reclassification and discrimination for ND(net reclassification index = 0.510, P = 0.002; integrated discrimination improvement = 0.072, P < 0.001). Conclusions The EIT parameters have been demonstrated to be an effective means of predicting ND following TAAR. Cerebral EIT may represent a potential alternative for intraoperative noninvasive multimodal neuromonitoring options. The findings of this study require further validation in further research.