Neurological recovery by EEG bursting after resuscitation from cardiac arrest in rats

Introduction: The return of neurological function during the early period after resuscitation from cardiac arrest (CA) has not been evaluated systematically. We report the temporal analysis of EEG bursting pattern during the very early periods after resuscitation. Design/method: A balanced group of good and poor outcome animals was selected from a population of rats subjected to either 5 or 7 min of asphyxial cardiac arrest (ACA) on the basis of a single criteria: 24 h neurobehavioral function based on the neurodeficit score (NDS). The EEGs of six consecutive good outcome rats (NDS≥60) and six consecutive poor outcome rats (NDS<60) were selected for the study. The EEGs of these animals were given to two EEG examiners who were blinded to the selection process, the experimental conditions and the neurobehavioral recovery. The EEG bursting characteristics, such as rate, peak and duration of bursting were studied. Results: There was significantly higher EEG bursting in the good outcome animals (P<0.05) and the burst complexes evolved into continuous activity by 90 min. Lower frequency bursting that persisted and failed to evolve into continuous activity was observed in the poor outcome group. Conclusion: Increased EEG bursting during first 30-40 min after resuscitation from moderate to severe ACA was observed in rats with good neurological outcome at 24 h. Early EEG bursting patterns may provide additional prognostication after resuscitation from CA.