THE IMPROVED OXYGENATION OF PRETERM INFANTS DURING NON-NUTRITIVE SUCKING DEPENDS ON POSTCONCEPTIONAL AGE

Abstract

Non-nutritive sucking (NNS) has been reported to stabilize transcutaneous (tc) PO2 in preterm infants during both gavage feeding and assisted ventilation. To evaluate the effect of NNS in the resting preterm infant, we measured TcPO2, heart rate (HR) and resp. rate in 14 healthy, sleeping infants (G.A. at birth 26-33 wk, B.Wt 710-1450g). Each study was begun in active sleep, and comprised 15 min. of data collection divided into 3 equal periods: preNNS, NNS and postNNS. Sucking was recorded with a pacifier adapted to measure sucking pressure, and respiration was detected with a nasal thermistor. Subjects were studied at two weekly intervals until discharge and divided into 4 groups based on postconceptional age.During NNS, TcPO2 increased 2.3±0.9 mmHg at 32-33 wk (p<.01) and 4.0±1.5 mmHg at 34-35 wk (p<.05). In contrast, TcPO2 did not increase during NNS at either 36-37 or 38-39 wk. HR increased during NNS in all 4 groups although this was only significant at 34-35 wk (p<.01) and 36-37 wk (p<.02), while resp. rate never changed. Time spent in active sleep during the 5 min. epochs did not differ between the 3 periods and ranged from 61% to 96%. Thus the increase in TcPO2 during NNS is dependent on the infant's postconceptional age and does not appear to be due to a change in resp. rate or sleep state. These data suggest that providing an opportunity for NNS may be a beneficial intervention in the care of healthy preterm infants between 32 and 35 wk postconceptional age.