VARIATIONS IN ASPHYXIAL GASPING WITH FETAL AGE IN LAMBS AND GUINEA‐PIGS

Abstract

The time to the last gasp after tying the umbilical cord was measured in fetal lambs and guinea‐pigs of different gestation ages; body temperature was maintained. At two‐thirds of term the times to the last gasp were slightly but significantly greater than at full term in both species. But at about 0·34 (lamb) and 0·46 of term (guinea‐pig) the times to the last gasp were very much less than in mature fetuses. In lambs a third of the way through gestation the short time to the last gasp could not be attributed to hypoglycaemia, circulatory collapse or neuro‐muscular failure. The results suggest that at this age the respiratory centre may be more susceptible to asphyxia, yet post‐asphyxial recovery occurred rapidly. © 1972 The Physiological Society