Abstract 2408: Electrophysiologic Monitoring Of Neurological Recovery With Temperature Manipulation After Cardiac Arrest In Rats
Background Therapeutic hypothermia after cardiac arrest (CA) improves survival and functional outcomes, while hyperthermia is harmful. The optimal tool for tracking the effect of temperature manipulation on recovery of cortical electrical function has not been elucidated. Previously, we demonstrated that good neurological recovery is associated with higher relative electroencephalographic (EEG) entropy, measured by information quantity (IQ).
Methods We investigated the effect of temperature manipulation on neurological recovery after asphyxial CA in a rodent model using quantitative EEG (qEEG). Twenty-four rats were evenly divided into 3 groups (n=8 per group, randomly assigned), based on 6 hours of hypothermia (T=33°C), normothermia (T=37°C) or hyperthermia (T=39°C) immediately after resuscitation from 7-minute asphyxial CA. Temperature was maintained using surface cooling and warming. Neurological recovery was evaluated using serial Neurological Deficit Score (NDS) calculation.
Results Greater recovery of IQ was found in rats treated with hypothermia (0.74±0.03), compared to normothermia (0.60±0.03) and hyperthermia (0.56±0.03) (p<0.001). qEEG analysis at different intervals demonstrated a significant separation of IQ scores between the groups only within the first 2 hours of resuscitation (p<0.01). The 72-hour NDS of the hypothermia group (74, 61–74; Median, 25th–75th percentile) was also significantly improved compared to the normothermia (49, 47– 61) and hyperthermia (43, 0 –50) groups (p<0.001). The IQ values correlated strongly with the 72-hour NDS as early as 30 minutes after resuscitation (Pearson correlation 0.735, 2-tailed significance p=0.01) and maintained a significant association throughout the 72-hour experiment.
Conclusions Early qEEG was sensitive to the benefit of hypothermia as well as the harmful effect of hyperthermia post-CA and predicted neurological recovery at 72 hours.