Can BIS monitoring be used to assess the depth of propofol anesthesia in the treatment of refractory status epilepticus?

Abstract

Appropriate treatment of generalized convulsive refractory status epilepticus (RSE) requires general anesthesia in the intensive care unit (ICU) with continuous electroencephalography (cEEG) monitoring. During out of office hours and weekends, cEEG monitoring is not always available. The Bispectral Index (BIS) monitor can be used to assess the hypnotic component of general anesthesia. We conducted a study to evaluate the feasibility of using the BIS monitoring to assess the burst suppression (BS) pattern during propofol anesthesia in RSE. Ten adult patients with RSE admitted to the ICU were monitored simultaneously with cEEG and BIS monitoring. We compared the BIS and suppression ratio (SR) values with the EEG burst suppression pattern when the depth of anesthesia was titrated to the BS level monitoring by cEEG. We found an excellent correlation between the cEEG burst rate per minute and the BIS (r² =-0.9; p< 0.001) and SR (r² = -0.88; p < 0.001). The sensitivity and specificity of BIS score of 30 to detect BS in electroencephalography were 99% and 98%, respectively. The BIS monitor was not able to recognize regional epileptic activity and epileptic bursts during the BS pattern. The cEEG can be considered as the primary monitoring technique in the assessment of the depth of anesthesia in the treatment of RSE. If cEEG is not available, the BIS monitor can be used to guide the level of anesthesia, targeting BS in patients with RSE.