Abstract 161: The Product of End Tidal Carbon Dioxide and an Electroencephalogram Measurement Correlates With Cerebral Perfusion Pressure During Cardiopulmonary Resuscitation in a Swine Model of Cardiac Arrest
Background: Non-invasive markers are lacking to assess cerebral function and perfusion during CPR. For >25 years ETCO2 values during CPR have been shown to correlate with coronary perfusion pressure and clinical outcomes. Further, electroencephalograms (EEG) have been used to measure brain wave activity but generally have not been shown to correlate with clinical outcomes during or after CPR. We hypothesized that a combined signal, incorporating measurements of both ETCO2 and an EEG, assessed with a bispectral index (BIS), correlates with cerebral perfusion pressure (CerPP) during CPR. A strong positive signal may provide an innovative way to predict successful resuscitation with favorable neurological outcome.
Methods: Five female farm pigs (38 ± 3 kg) were studied using a model of cardiac arrest. Following surgical preparation, isoflurane was discontinued. Once the BIS value was 60-70, ventricular fibrillation (VF) was induced. After 4 minutes of untreated VF, three different methods of CPR [standard CPR (S-CPR), active compression decompression (ACD) CPR plus an impedance threshold device (ACD-ITD), and ACD plus an intrathoracic pressure regulator (ACD-IPR)] were performed sequentially for 4 minute epochs. Millar catheters were used to measure aortic (AO) and intracranial pressures (ICP). BIS values and suppression ratio (SR) were monitored. Results are reported as mean ± SEM. A Spearman rank test was used to correlate the product of BISxETCO2 with CerPP during CPR.
Results: The Spearman rank coefficient was statistically significant between the BISxETCO2 product and CerPP (correlation coefficient=0.56, p=0.03) as shown in Fig. 1. SR was between 0-5 in all CPR interventions.
Conclusion: These findings support the hypothesis that a new index, the product of an EEG BIS signal and ETCO2 varied in a manner that correlates with CerPP during CPR. Further studies to determine if this non-invasive neurological index is predictive of awakening in pigs are underway.
- © 2013 by American Heart Association, Inc.