Presented at the Neonatal Society 2002 Summer Meeting.

Murdoch EM, Sinha AK, Kempley ST

Department of Child Health, Queen Mary University of London 
Neonatal Unit, Royal London Hospital E1 1BB, UK

Background: In preterm infants, the first enteral feed results in an increase in superior mesenteric artery (SMA) blood flow velocity (1). Although small-for-gestational-age (SGA) preterm infants have reduced SMA velocity on the first day of life (2), their response to enteral feeding is not known.

Aim: To compare the splanchnic haemodynamic response to the first feed in preterm SGA and appropriately grown (AGA) preterm infants.

Methods: Preterm infants admitted to the neonatal unit were defined as SGA if their birthweight was <2nd centile, or <9th centile with evidence of fetal blood flow redistribution. Blood flow velocity was measured from the superior mesenteric artery and coeliac axis (CA), using Doppler ultrasound. The time averaged mean velocity and pulsatility index (PI) was obtained from 5 consecutive arterial waveforms. Measurements were taken on the first day of life, then repeated before and after a standardised first enteral feed. First day measurements were compared using Students t-test; feeding studies were analysed using ANOVA.

Results: Values are means (SD). Difference between SGA (*=p<. 05, ***=p<. 001)

The SMA and CA velocity were reduced on the first day in SGA infants. Baseline SMA velocity at the time of the first feed was similar in both groups, but only AGA infants demonstrated a rise in SMA velocity following feeding. Coeliac velocity remained lower in the SGA group throughout and was unaffected by feeding.

Conclusions: Different postnatal effects were seen in the circulations studied. SGA infants did not show a mesenteric response to feeding, even after recovery of baseline SMA velocity. They had a persistent reduction in coeliac axis velocity.

References:
1. Gladman G Arch Dis Child 1991; 66:17-20.
2. Kempley ST Arch Dis Child 1991; 65:115-18.