Background
Maintenance of brain cell viability is the most important goal of cardiopulmonary resuscitation (CPR) in cardiac arrest. We have developed an non-invasive and single-channel EEG-based Brain Resuscitation Index (EBRI) that can be used to measure the brain cell viability. The purpose of this study is to evaluate whether high-quality (HQ) and low-quality (LQ) CPR can be distinguished using the EBRI.
Methods
A random case-crossover experimental animal study using porcine cardiac arrest model was performed. After 1 minute of untreated ventricular fibrillation, HQ-CPR (compression depth 5 cm and compression rate 100 per min) and LQ-CPR (compression depth 3 cm and compression rate 60 per min) were alternated every 50 seconds and repeated 10 cycles overall for five pigs. The computing formula of the EBRI was developed to predict the end-tidal CO2 (ETCO2) value using a single-channel EEG signals attached to forehead. The EEG signals were continuously measured and calculated simultaneously with the EBRI. Receiver operating characteristic of the area under the curve (ROC-AUC) was used to compare the discrimination power of HQ-CPR versus LQ-CPR. We compared the ROC-AUCs of two EBRI models reflecting time lags )o seconds to 16 seconds) between CPR change (HQ to LQ or LQ to HQ) and measurement of EBRI) comparing with ETCO2 itself.
Results
Demographics of vital signs and hemodynamic parameters were significantly different between HQ- versus LQ-CPR. (Table 1) The ETCO2 and various models of EBRI with different time lags were concordantly displayed according to HQ- and LQ-CPR alteration in Figure 1. When comparing the AUC-ROC of EBRI models with various time lags for HQ-CPR versus LQ-CPR, the EBRI with 8 seconds time lag model showed the highest value; 0.86 (0,86-0,87). The AUC-ROC of ETCO2 itself showed 0.67 (0.66-0.68).  
Conclusion
A non-invasive and single-channel EEG-based brain resuscitation index than ETCO2 showed the higher performance for discriminating high-and low-quality CPR in a case-crossover animal study.

4 - discrimination performance of a non-invasive and single-channel electroencephalography-based brain cell viability for comparing high versus low quality cardiopulmonary resuscitation; a porcine cardiac arrest experimental study