Ventilatory and arousal responses of sleeping lambs to respiratory challenges: effect of prenatal maternal anemia

We have examined the effects of exposure to chronic maternal anemia, throug hout the final one-third of gestation, on postnatal ventilatory and arousal responses to hypoxia, hypercapnia, and combined hypoxia-hypercapnia in sle eping lambs. While resting quietly awake, lambs from anemic ewes had higher arterial PCO2 levels than control animals during the first 2-3 postnatal w k, but pH, arterial PO2, and arterial O-2 saturation were not different. Du ring active and quiet sleep lambs from anemic ewes had higher end-tidal CO2 levels than control animals when breathing room air and at the time of spo ntaneous arousal or when aroused by progressive hypercapnia or by combined hypoxia-hypercapnia. Ventilation and arterial O-2 saturation during uninter rupted sleep and ventilatory responsiveness to hypoxia (inspiratory O-2 fra ction, 10%), progressive hypercapnia, and combined hypoxia/hypercapnia were not significantly affected by exposure to maternal anemia. Our findings sh ow that maternal anemia results in elevated PCO2 levels in the offspring. T his effect may be due, at least in part, to altered pulmonary function.