Abstract 28: Serial Changes in Bispectral Index From Soon After ROSC in Post-Cardiac Arrest Syndrome Patients
Introduction: Bispectral index (BIS) was reported to be an early neurological predictor in unconscious post-cardiac arrest syndrome (PCAS) patients. However, the BIS information for such devastating situation is still limited. We examined serial changes in BIS variables from immediately after ROSC to 72 hours in PCAS patients.
Methods: In consecutive unconscious twenty-five PCAS patients, using the BIS monitor, we examined the time-course changes in BIS (an arousal index combining EEG with EMG) and suppression ratio (SR: a ratio of cortical silence in the EEG) from soon after ROSC. All patients were continuously administered a muscle relaxant, which allows us to obtain pure EEG signals without EMG in the BIS monitor. Mann-Whitney U-test or chi-square test was used for statistical analysis (p<0.05). Sensitivity (se.) and specificity (sp.) of BIS values and SRs as the neurological predictors were also examined.
Results: PCAS patients showing “zero BIS values” soon after ROSC did not recover their consciousness, or went into brain death. Such patients had reciprocally extreme high levels of SRs. BIS values less than 20 (se. 95%, sp. 100%,) and SRs more than 80 (se. 99%, sp. 100%) predicted unfavorable outcome in the whole data until 72 hours after ROSC. Exceptionally, a PCAS patient showing around 10 of BIS values and 80 of SRs immediately after ROSC recovered to moderate disability.
Conclusions: BIS value and SR are reliable indexes predicting neurological outcome in unconscious PCAS patients. However, we should be careful on determining neurological prognosis of PCAS patients showing certain levels of BIS and SR immediately after ROSC.
- © 2010 by American Heart Association, Inc.