262 Glucose and Insulin Inhibit Fetal Lung Maturation in Vitro

Abstract

The cardio-respiratory response to hypoxia is the subject of intense research in human infants, but is mostly limited to noninvasive studies. Animal investigation is an attractive alternative, but most animal studies have involved anesthetized or nonintact preparations, which may not reflect human physiology. The cardio-respiratory responses to hypoxia are not well documented in unanesthetized intact newborn animals. In particular, there is little information on the periodic breathing (PB) response to hypoxia and, hence, on the practicality of an animal model for PB.-We studied heart rate (HR) and respiratory responses during quiet sleep to 17% Fl0 2 in unanesthetized full-term newborns of five species; lamb, piglet, puppy, kitten, and rabbit (N=31). ECG, HR and respirogram monitoring was used. There was no significant change in mean HR and respiratory rate (RR) with hypoxia for any species. Brief apneas > 5 sec. were