Abstract 156

Aims: To investigate the influence of orogastric tube feeding(OTF) on cerebral blood flow velocities (CBFV), blood pressure and heart rate in healthy preterm infants.

Subjects: Eleven preterm infants (BW 1278±168 g and GA 30.5±2 wks) were studied at weekly intervals during the first three postnatal weeks (PNWs).

Measurements: CBFV measured using pulsed-wave duplex-Doppler ultrasound, were assessed from the anterior cerebral artery prior to, during, and 10 and 20 min after OTF. Non-invasive blood pressure (RR) recordings followed CBFV measurements. Heart rate (HR) was continuously recorded by cardiorespirograph during the 1 hour procedure. A mean of 18±8 ml/kg/feed of preterm milk-formula were administered via a mechanical pump over a 10 min period. The infants were placed in prone, and the studies were videorecorded. Data were analyzed separately for each PNW (n=11) using repeated measures analysis (SAS).

Results: The cardiovascular response to feeding differed in the first 3 PNWs. In the 1st PNW, a significant decrease of RR in the postfeed periods (p<0.01) was associated with a significant increase of HR(p<0.05), maintaining a constant CBFV. In the 2nd PNW, no significant change in RR, but a highly significant increase of HR in the postfeed periods (p<0.001) maintained a constant CBFV. Finally, in the 3rd PNW, no significant changes of RR and HR were associated with a significant postprandial increase of peak-systolic blood flow velocity only(p<0.05).

Conclusions: Healthy preterm infants are able to maintain their preprandial CBFV as measured up to 20 min postfeed. However, the mechanism of systemic circulatory response to feeding shows a postnatal maturation.