Reduced neural activity during volatile anesthesia compared to TIVA: evidence from a novel EEG signal processing analysis

TL;DR

This study compares brain activity during volatile anesthesia and TIVA using EEG signals, revealing that volatile anesthesia significantly reduces neural activity, especially in features linked to cognitive decline, which may impact post-operative recovery.

Contribution

It introduces a novel EEG signal processing approach to differentiate the effects of anesthesia types on brain activity during surgery.

Findings

Volatile anesthesia reduces delta, theta, and alpha activity compared to TIVA.

Feature A0 shows the largest difference and correlates with cognitive decline.

EEG features can distinguish effects of anesthesia types on brain function.

Abstract

Post-operative cognitive decline is a well-known phenomenon and of crucial importance especially in the elderly. General anesthesia can be accomplished by inhalation-based (volatile) or total intravenous anesthesia (TIVA). While their effects on post-operative symptoms have been investigated, little is known about their influence on brain functionalities during the surgery itself. To assess differences 17 patients were divided to receive either volatile anesthesia (n=9), or TIVA (n=8). The level of anesthesia was kept to be equal in both groups. A single bipolar EEG electrode (Neurosteer system) was placed on the participants foreheads. It presented real-time activity and collected their data during the surgery. The dependent variables included frequency bands (delta, theta, alpha, and beta), and three features (VC9, ST4, and A0) previously extracted with the device and provided by Neurosteer. All surgeries were uneventful, and all patients showed bispectral index (BIS) score less than 60. Feature activity under volatile anesthesia (in comparison to TIVA) was significantly lower for the delta, theta and alpha frequency bands and for the three features. Further analysis showed that the largest difference between anesthesia types was for feature A0. The EEG frequency bands and novel brain activity features provide evidence that volatile anesthesia further reduces components of brain activity in comparison to TIVA anesthesia. Specifically, A0, which previously showed a correlation with cognitive decline severity and cognitive load, exhibited the most prominent difference between anesthesia types. Together, this study suggests that measuring brain activity during anesthesia using sensitive features, enables revealing that different anesthesia types may affect brain activity differently, which could affect the recovery from anesthesia, and consequently reduce post-operative cognitive decline