Cerebral hypoxic ischemia at different cerebral oxygen saturations in piglets: amplitude-integrated EEG study

Objective: the objective of present paper was to study the amplitude-integrated EEG (aEEG) in hypoxic ischemic (HI) animal models and to test the reliability of aEEG method when used to monitor cerebral injuries. Method: HI animal models were constructed and classified into mild, moderate and severe cerebral oxygen saturation groups according to regional oxygen saturation (rSO2) in brains. Then aEEG waveforms were obtained from raw EEG data using digital signal processing. Result: aEEG reflected cerebral functions consistently and accurately at different cerebral rSO2 levels. aEEG waveforms rarely changed in the group of mild HI; they dropped but recovered in moderate HI group; and aEEG maintained very low after HI in the cases when severe HI happened. Conclusion: aEEG method could monitor cerebral functions directly, accurately and consistently. It is a reliable tool to continuously evaluate cerebral injuries.