Measurement of visual evoked potential in the asphyctic fetus and during neonatal survival

Abstract

Visual evoked potentials were measured in eight exteriorized near-term fotal lambs prior to and during 8 minutes of asphyxia and during 1 hour of newbom survival. Four of the lambs were then extubated, and measurements were continued while the lambs were observed for behavior and gross motor function. Early in the aspnyctic period marked changes in the visual evoked potential occurred in association with a fall in Po2, whereas during the postexposure period the visual evoked potential appeared to recover independently of caidiovascular or arterial blood gas values. Moreover, early wave components of the visual evoked potential were more resistant to asphyxia than were later components and resporded more quickly to resuscitative efforts. During the survival period the visual evoked potential did not correlate with gross motor function when animals were exposed to moderate acidosis. After severe acidosis abnormal visual evoked potentials were seen during periods of clinical deterioration.