Spatial variation in automated burst suppression detection in pharmacologically induced coma

Abstract

Burst suppression is actively studied as a control signal to guide anesthetic dosing in patients undergoing medically induced coma. The ability to automatically identify periods of EEG suppression and compactly summarize the depth of coma using the burst suppression probability (BSP) is crucial to effective and safe monitoring and control of medical coma. Current literature however does not explicitly account for the potential variation in burst suppression parameters across different scalp locations. In this study we analyzed standard 19-channel EEG recordings from 8 patients with refractory status epilepticus who underwent pharmacologically induced burst suppression as medical treatment for refractory seizures. We found that although burst suppression is generally considered a global phenomenon, BSP obtained using a previously validated algorithm varies systematically across different channels. A global representation of information from individual channels is proposed that takes into account the burst suppression characteristics recorded at multiple electrodes. BSP computed from this representative burst suppression pattern may be more resilient to noise and a better representation of the brain state of patients. Multichannel data integration may enhance the reliability of estimates of the depth of medical coma.

Figure 1

Burst Suppression Probability Model Used in Analysis

Figure 2

AI) Illustration of Variation in Single Channel BSP. Data from Fp1, F3 C3, P3 and O1 (left side medial anterior to posterior) channels of a patient with post-anoxic refractory status epilepticus. AII) Demonstration of Suppression Pattern Detection. This is a 1 min segment taken from the location of the vertical dashed line in Fig. 2AI. Note that the green box highlights a burst that is only observed in frontal lead Fp1 but not C3 or O1 while the orange box encases a burst that is similarly detected across all three channels. BI) Demonstration of Global BSP overlaid on all Single Channel BSP. Data from post anoxic RSE patient described in Fig 2AI and 2AII. BII) Demonstration of Global BSP Overlaid on All Single Channel BSP. Data from a non-anoxic RSE patient. Blue block indicates a location where one of the electrodes was an outlier. Global BSP was not affected by this outlier. C) Summary of Mean and Standard Deviation of Single Channel BSP difference from Global BSP Averaged Across pRSE and npRSE Groups. Note that pRSE patients have higher mean differenace and standard deviation in comparison to the npRSE group