Early auditory evoked potential changes during hypoxic hypoxia in the rabbit.

Early auditory evoked potentials and electroencephalograms were recorded in 10 rabbits during hypoxic hypoxia (5% O2 in N2 gas mixture) and after reoxygenation. In all experiments EEG flattening preceded the disappearance of the early evoked potential, whose recovery after reoxygenation was more rapid than that of the EEG. Significant increases in P3-P4 and P1-P3 interpeak latencies were observed during hypoxic conditions before the complete flattening of the early auditory evoked potential. In addition, negative relationships were found between the P3-P4 interpeak latency increase and mean arterial pressure reduction, and between the former and metabolic acidosis.