Neuromonitoring with Intermittent Transcranial Doppler Sonography and Continuous Near Infrared Spectroscopy in Aortic Arch Surgery: An Observational Study

Abstract

Background Aortic Arch repair for aortic dissection is still associated with a high mortality rate. Adequate means of neuromonitoring to guide cerebral hemodynamics, especially during selective anterior cerebral perfusion (SACP) are desirable. It is possible that this cannot be achieved by one monitoring modality alone. It was the objective of this study to investigate an easy multimodal monitoring setup consisting of EEG, near infrared spectroscopy (NIRS) and transcranial doppler sonography. Methods Patients with surgery for aortic dissection were included. In addition to standard hemodynamic monitoring, patients received continuous bilateral NIRS, processed EEG with bispectral index (BIS) and intermittent transcranial doppler sonography of the medial cerebral artery (MCA) with a standard B-mode ultrasound device. Doppler measurements were taken bilaterally before cardiopulmonary bypass (CPB), during CPB and during the selective brain perfusion phase in regular intervals Results Six patients with aortic dissection could be included. Two patients died, one in the operating room and one on ICU. Four patients survived without neurological deficit. Two, however, suffered from transient postoperative delirium. Multimodal monitoring led to change in CPB flow or cannula repositioning in 3 patients (50%). Left sided mean flow velocities of the MCA significantly decreased during selective brain perfusion (p = 0.028), as did BIS values (p = 0.028) Conclusions Multimodal monitoring consisting of BIS, NIRS and B-Mode transcranial sonography can have an impact on hemodynamic management in aortic arch operations. More research is needed to establish target parameters of cerebral perfusion.